Mahjongg - Revision history

Mahjongg at 14:29, 10 March 2023

2023-03-10T14:29:59Z

← Older revision		Revision as of 14:29, 10 March 2023
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	* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface_for_the_ZX-81		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface_for_the_ZX-81

	* I'm also busy building a very much simplified and tiny version of a TZXDuino. I have got a TZXDuino kit working which is used at the National VideoGame Museum in Zoetermeer, where I am a volunteer. It is used to upload a game each day onto the Sinclair Spectrum 48K (model 3) that is in the home computer part of the museum, ~~ext~~ to a C64, a Philips MSX-2 and a Amiga 500, all of which run a game to use, except for the Spectrum. The spectrum has been modified with a low power loss switching 5Volt regulator, so it doesn't get hot anymore, it has its keyboard foil replaced, and uses an 16K EEPROM which holds two copies of the 8K ROM, with a hidden switch to select which half of the ROM was used. In the past one of the copies was replaced with a game that was available in cartridge format, but built into the Spectrum, but there were only 10 different cartridges ever made, and none of the available games had an attract mode, so the game only offered a simple black and white menu. Not suitable for use in our museum. The TZXDuino is now used to load an attractive game into the Spectrum. Most often Manic Miner is used. But getting the TZXDuino every day, and 5 minutes later removing it is a bit of a chore, so I ~~want~~ to replace it with a buit in version, needing just two hidden buttons, and no screen. so all the operator has to do is to enter LOAD "" on the spectrum, and pushing a ~~single button~~ to start the TZXDuino hidden inside the Spectrum, after that he can simply walk away knowing that the upload process will never fail. for design information see: https://revspace.nl/TZXDuino_pico		* I'm also busy building a very much simplified and tiny version of a TZXDuino. I have got a TZXDuino kit working which is used at the National VideoGame Museum in Zoetermeer, where I am a volunteer. It is used to upload a game each day onto the Sinclair Spectrum 48K (model 3) that is in the home computer part of the museum, next to a C64, a Philips MSX-2 and a Amiga 500, all of which run a game to use, except for the Spectrum. The spectrum has been modified with a low power loss switching 5Volt regulator, so it doesn't get hot anymore, it has its keyboard foil replaced, and uses an 16K EEPROM which holds two copies of the 8K ROM, with a hidden switch to select which half of the ROM was used. In the past one of the copies was replaced with a game that was available in cartridge format, but built into the Spectrum, but there were only 10 different cartridges ever made, and none of the available games had an attract mode, so the game only offered a simple black and white menu. Not suitable for use in our museum. The TZXDuino is now used to load an attractive game (with an attract mode§)into the Spectrum. Most often Manic Miner is used. But getting the TZXDuino every day, and 5 minutes later removing when the game was loaded was is a bit of a chore, so I went to replace it with a buit in version, needing just two hidden buttons, and no screen. so all the operator has to do is to enter LOAD "" on the spectrum, and pushing a two buttons to start the TZXDuino hidden inside the Spectrum, after that he can simply walk away knowing that the upload process will never fail. for design information see: https://revspace.nl/TZXDuino_pico

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl

Mahjongg at 14:17, 10 March 2023

2023-03-10T14:17:46Z

← Older revision		Revision as of 14:17, 10 March 2023
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	* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface_for_the_ZX-81		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface_for_the_ZX-81

	* I'm also busy building a very much simplified and tiny version of a TZXDuino. I have got a TZXDuino kit working which is used at the National VideoGame Museum in Zoetermeer, where I am a volunteer. It is used to upload a game each day onto the Sinclair Spectrum 48K (model 3) that is in the home computer part of the museum, ext to a C64, a Philips MSX-2 and a Amiga 500, all of which run a game to use, except for the Spectrum. The spectrum has been modified with a low power loss switching 5Volt regulator, so it doesn't get hot anymore, it has its keyboard foil replaced, and uses an 16K EEPROM which holds two copies of the 8K ROM, with a hidden switch to select which half of the ROM was used. In the past one of the copies was replaced with a game that was available in cartridge format, but built into the Spectrum, but there were only 10 different cartridges ever made, and none of the available games had an attract mode, so the game only offered a simple black and white menu. Not suitable for use in our museum. The TZXDuino is now used to load an attractive game into the Spectrum. Most often Manic Miner is used. But getting the TZXDuino every day, and 5 minutes later removing it is a bit of a chore, so I want to replace it with a buit in version, needing just two hidden buttons, and no screen. so all the operator has to do is to enter ~~CLOAD~~ "" on the spectrum, and pushing a single button to start the TZXDuino hidden inside the Spectrum, after that he can simply walk away knowing that the upload process will never fail. for design information see: https://revspace.nl/TZXDuino_pico		* I'm also busy building a very much simplified and tiny version of a TZXDuino. I have got a TZXDuino kit working which is used at the National VideoGame Museum in Zoetermeer, where I am a volunteer. It is used to upload a game each day onto the Sinclair Spectrum 48K (model 3) that is in the home computer part of the museum, ext to a C64, a Philips MSX-2 and a Amiga 500, all of which run a game to use, except for the Spectrum. The spectrum has been modified with a low power loss switching 5Volt regulator, so it doesn't get hot anymore, it has its keyboard foil replaced, and uses an 16K EEPROM which holds two copies of the 8K ROM, with a hidden switch to select which half of the ROM was used. In the past one of the copies was replaced with a game that was available in cartridge format, but built into the Spectrum, but there were only 10 different cartridges ever made, and none of the available games had an attract mode, so the game only offered a simple black and white menu. Not suitable for use in our museum. The TZXDuino is now used to load an attractive game into the Spectrum. Most often Manic Miner is used. But getting the TZXDuino every day, and 5 minutes later removing it is a bit of a chore, so I want to replace it with a buit in version, needing just two hidden buttons, and no screen. so all the operator has to do is to enter LOAD "" on the spectrum, and pushing a single button to start the TZXDuino hidden inside the Spectrum, after that he can simply walk away knowing that the upload process will never fail. for design information see: https://revspace.nl/TZXDuino_pico

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl

Mahjongg at 12:27, 12 October 2022

2022-10-12T12:27:12Z

← Older revision		Revision as of 12:27, 12 October 2022
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	* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface_for_the_ZX-81		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface_for_the_ZX-81

	* I'm also busy building a very much simplified and tiny version of a TZXDuino. I have got a TZXDuino kit working which is used at the National VideoGame Museum in Zoetermeer, where I am a volunteer. It is used to upload a game each day onto the Sinclair Spectrum 48K (model 3) that is in the home computer part of the museum, ext to a C64, a Philips MSX-2 and a Amiga 500, all of which run a game to use, except for the Spectrum. The spectrum has been modified with a low power loss switching 5Volt regulator, so it doesn't get hot anymore, it has its keyboard foil replaced, and uses an 16K EEPROM which holds two copies of the 8K ROM, with a hidden switch to select which half of the ROM was used. In the past one of the copies was replaced with a game that was available in cartridge format, but built into the Spectrum, but there were only 10 different cartridges ever made, and none of the available games had an attract mode, so the game only offered a simple black and white menu. Not suitable for use in our museum. The TZXDuino is now used to load an attractive game into the Spectrum. Most often Manic Miner is used. But getting the TZXDuino every day, and 5 minutes later removing it is a bit of a chore, so I want to replace it with a buit in version, needing just two hidden buttons, and no screen. so all the operator has to do is to enter CLOAD "" on the spectrum, and pushing a single button to start the TZXDuino hidden inside the Spectrum, after that he can simply walk away knowing that the upload process will never fail.		* I'm also busy building a very much simplified and tiny version of a TZXDuino. I have got a TZXDuino kit working which is used at the National VideoGame Museum in Zoetermeer, where I am a volunteer. It is used to upload a game each day onto the Sinclair Spectrum 48K (model 3) that is in the home computer part of the museum, ext to a C64, a Philips MSX-2 and a Amiga 500, all of which run a game to use, except for the Spectrum. The spectrum has been modified with a low power loss switching 5Volt regulator, so it doesn't get hot anymore, it has its keyboard foil replaced, and uses an 16K EEPROM which holds two copies of the 8K ROM, with a hidden switch to select which half of the ROM was used. In the past one of the copies was replaced with a game that was available in cartridge format, but built into the Spectrum, but there were only 10 different cartridges ever made, and none of the available games had an attract mode, so the game only offered a simple black and white menu. Not suitable for use in our museum. The TZXDuino is now used to load an attractive game into the Spectrum. Most often Manic Miner is used. But getting the TZXDuino every day, and 5 minutes later removing it is a bit of a chore, so I want to replace it with a buit in version, needing just two hidden buttons, and no screen. so all the operator has to do is to enter CLOAD "" on the spectrum, and pushing a single button to start the TZXDuino hidden inside the Spectrum, after that he can simply walk away knowing that the upload process will never fail. for design information see: https://revspace.nl/TZXDuino_pico

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl

Mahjongg at 14:50, 8 October 2022

2022-10-08T14:50:13Z

← Older revision		Revision as of 14:50, 8 October 2022
Line 55:		Line 55:

	* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface_for_the_ZX-81		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface_for_the_ZX-81

			* I'm also busy building a very much simplified and tiny version of a TZXDuino. I have got a TZXDuino kit working which is used at the National VideoGame Museum in Zoetermeer, where I am a volunteer. It is used to upload a game each day onto the Sinclair Spectrum 48K (model 3) that is in the home computer part of the museum, ext to a C64, a Philips MSX-2 and a Amiga 500, all of which run a game to use, except for the Spectrum. The spectrum has been modified with a low power loss switching 5Volt regulator, so it doesn't get hot anymore, it has its keyboard foil replaced, and uses an 16K EEPROM which holds two copies of the 8K ROM, with a hidden switch to select which half of the ROM was used. In the past one of the copies was replaced with a game that was available in cartridge format, but built into the Spectrum, but there were only 10 different cartridges ever made, and none of the available games had an attract mode, so the game only offered a simple black and white menu. Not suitable for use in our museum. The TZXDuino is now used to load an attractive game into the Spectrum. Most often Manic Miner is used. But getting the TZXDuino every day, and 5 minutes later removing it is a bit of a chore, so I want to replace it with a buit in version, needing just two hidden buttons, and no screen. so all the operator has to do is to enter CLOAD "" on the spectrum, and pushing a single button to start the TZXDuino hidden inside the Spectrum, after that he can simply walk away knowing that the upload process will never fail.

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl

Mahjongg: arrrgh

2022-04-12T16:56:39Z

arrrgh

← Older revision		Revision as of 16:56, 12 April 2022
Line 54:		Line 54:
	* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit. It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone		* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit. It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone

	* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-~~card_interface for the ZX~~-81		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface_for_the_ZX-81

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl

Mahjongg at 16:55, 12 April 2022

2022-04-12T16:55:28Z

← Older revision		Revision as of 16:55, 12 April 2022
Line 54:		Line 54:
	* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit. It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone		* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit. It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone

	* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/~~ZONX81plus4_PSG_Board_with_sd~~-card_interface for the ZX-81		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus41_PSG_Board_with_sd-card_interface for the ZX-81

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl

Mahjongg at 16:53, 12 April 2022

2022-04-12T16:53:21Z

← Older revision		Revision as of 16:53, 12 April 2022
Line 54:		Line 54:
	* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit. It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone		* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit. It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone

	* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it ~~here:~~ https://revspace.nl/ZONX81plus4_PSG_Board_with_sd-card_interface		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it https://revspace.nl/ZONX81plus4_PSG_Board_with_sd-card_interface for the ZX-81

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl

Mahjongg at 16:47, 12 April 2022

2022-04-12T16:47:21Z

← Older revision		Revision as of 16:47, 12 April 2022
Line 54:		Line 54:
	* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit. It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone		* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit. It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone

	* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it here: https://revspace.nl/~~Zon_ZX~~-~~81_compatible_PSG_%2B_32K_RAM_and_SD-Card_interface_expansion_for_ZX-81_and_clones~~		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it here: https://revspace.nl/ZONX81plus4_PSG_Board_with_sd-card_interface

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl

Mahjongg at 16:39, 12 April 2022

2022-04-12T16:39:40Z

← Older revision		Revision as of 16:39, 12 April 2022
Line 26:		Line 26:
	links to my computer project pages are here:		links to my computer project pages are here:

	# a story about why I wanted to build a ZX-81 clone (A simple home built computer you can know completely) . https://revspace.nl/index.php?title=Zx81plus34		* a story about why I wanted to build a ZX-81 clone (A simple home built computer you can know completely) . https://revspace.nl/index.php?title=Zx81plus34

	# the complete design stages explained from beginning to working end and several intermediate versions. https://revspace.nl/ZX81PLUS34_ZX81_clone#28_February_2016_It.27s_alive.21		* the complete design stages explained from beginning to working end and several intermediate versions. https://revspace.nl/ZX81PLUS34_ZX81_clone#28_February_2016_It.27s_alive.21

	* I also designed a ZON compatible sound board (PSG based) for my ZX-81+34, which I wrote about here:https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35		* I also designed a ZON compatible sound board (PSG based) for my ZX-81+34, which I wrote about here:https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35
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	* I saw a possibility to built a working game system built into my own joypad, with a simple wire connected to a minimal "game system", that really only consisted of power, video and sound connector. It is based on the Raspberry PI zero computer. I found a way to directly connect pushbuttons to it, that with some software were converted to keyboard input that Retropie could use, and also found a way to create sound output (in stereo) using the standard GPIO's (a zero doesn't have audio outputs normall). using these ideas I built up a simple prototype on perfboard that worked perfectly, having good PAL composite output, and stereo sound. I decided to design a (series of) PCB's for it using KiCAD, and wrote about it here: https://revspace.nl/The_worlds_smallest_(S)NES_emulator		* I saw a possibility to built a working game system built into my own joypad, with a simple wire connected to a minimal "game system", that really only consisted of power, video and sound connector. It is based on the Raspberry PI zero computer. I found a way to directly connect pushbuttons to it, that with some software were converted to keyboard input that Retropie could use, and also found a way to create sound output (in stereo) using the standard GPIO's (a zero doesn't have audio outputs normall). using these ideas I built up a simple prototype on perfboard that worked perfectly, having good PAL composite output, and stereo sound. I decided to design a (series of) PCB's for it using KiCAD, and wrote about it here: https://revspace.nl/The_worlds_smallest_(S)NES_emulator

	* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.		* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit. It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone
	* This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit.
	* It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone

	* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it here: https://revspace.nl/Zon_ZX-81_compatible_PSG_%2B_32K_RAM_and_SD-Card_interface_expansion_for_ZX-81_and_clones		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it here: https://revspace.nl/Zon_ZX-81_compatible_PSG_%2B_32K_RAM_and_SD-Card_interface_expansion_for_ZX-81_and_clones

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl

Mahjongg at 16:38, 12 April 2022

2022-04-12T16:38:38Z

← Older revision		Revision as of 16:38, 12 April 2022
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	# the complete design stages explained from beginning to working end and several intermediate versions. https://revspace.nl/ZX81PLUS34_ZX81_clone#28_February_2016_It.27s_alive.21		# the complete design stages explained from beginning to working end and several intermediate versions. https://revspace.nl/ZX81PLUS34_ZX81_clone#28_February_2016_It.27s_alive.21

	# I also designed a ZON compatible sound board (PSG based) for my ZX-81+34, which I wrote about here:https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35		* I also designed a ZON compatible sound board (PSG based) for my ZX-81+34, which I wrote about here:https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35
			* because of complaints agains the use of SMT in a beginners project I started over, and with the experience gained from designing and testing the ZX81+34 I designed my ZX81+38 https://revspace.nl/ZX81plus38_simple_to_build_ZX-81_clone

	~~# because of complaints agains the use of SMT in a beginners project~~ I ~~started over, and with~~ the ~~experience gained from designing and testing the ZX81+34 I designed my ZX81+38~~ https://revspace.nl/~~ZX81plus38_simple_to_build_ZX-81_clone~~		* I wrote about the Galaksija here: https://revspace.nl/Galaksija I translated what little was know from the original Yugoslavian texts, so I could understand better how it worked. I also recovered the Schematics. In february 2022 I decided to build my own version of CMOS Galaksija, preliminary title PanGalaksija maybe I will rename it to PanGalaxy (a galaksija for the whole world)

	# I ~~wrote about~~ the ~~Galaksija here:~~ https://revspace.nl/Galaksija I translated what little was know from the original Yugoslavian texts, so I could understand better how it worked. I also recovered the Schematics. In february 2022 I decided to build my own version of CMOS Galaksija, preliminary title PanGalaksija maybe I will rename it to PanGalaxy (a galaksija for the whole world)		* in between both versions in 2017 I started on my own colour capable home computer the RhoCoCo, Z80 based system with 128K RAM and 64-color VGA output. https://revspace.nl/Designing_the_RhoCoCo_Retro_Home_COlor_COmputer_hardware

	~~# in between both versions in 2017~~ I ~~started on my own colour capable home computer~~ the ~~RhoCoCo, Z80 based system with 128K RAM and 64-color VGA output.~~ https://revspace.nl/~~Designing_the_RhoCoCo_Retro_Home_COlor_COmputer_hardware~~		* I wrote about the tribulations of ordering PCB's from China here: https://revspace.nl/Ordering_PCBs_for_rhococo but I ended up with 5 nice PCB's of the Rhococo main PCB and the single sided but larger keyboard PCB, it seems it makes hardly any difference anymore price wise between single sided and dual sided, its only the size that determines the price.

	# I wrote about ~~the tribulations of ordering PCB's from China~~ here: https://revspace.nl/Ordering_PCBs_for_rhococo but I ended up with 5 nice PCB's of the Rhococo main PCB and the single sided but larger keyboard PCB, it seems it makes hardly any difference anymore price wise between single sided and dual sided, its only the size that determines the price.		* I wrote about assembling Rhococo, and its keyboard on another wiki page here: https://revspace.nl/Assembling_RhoCoCo

	# I wrote about ~~assembling~~ Rhococo, and ~~its keyboard on another wiki page~~ here: https://revspace.nl/~~Assembling_RhoCoCo~~		* In april the same year I had built up my first prototype, and had successfully got it to work I wrote about bringing up (first boot) the hardware of the Rhococo here: https://revspace.nl/Bringing_up_Rhococo_(first_boot,_and_firmware_development) and found the first hardware bugs which I wrote about here: https://revspace.nl/Rhococo_prototype_hardware_debugging

	# In april the same year I had built up my first prototype, and had successfully got it to work I wrote about bringing up (first boot) the hardware of the Rhococo here: https://revspace.nl/Bringing_up_Rhococo_(first_boot,_and_firmware_development) and found the first hardware bugs which I wrote about here: https://revspace.nl/Rhococo_prototype_hardware_debugging		* I also thought about the possibilities to create an enclosure for RhoCoCo, and decided on using laser cut plywood, read here about that idea https://revspace.nl/Designing_an_enclosure_for_RhoCoCo

	# I also thought about the possibilities to create an enclosure for RhoCoCo, and decided on using laser cut plywood, read here about that idea https://revspace.nl/Designing_an_enclosure_for_RhoCoCo

	other stuff:		other stuff:
	# I repaired a Space invaders console, space invaders was one of the first game consoles that used a CPU, an intel 8080, the same hardware was first used by a cowboy fighting game, but that wan't very successful, it was Space invaders that first took of (after Atari's pong of course, but pong didn't use a CPU) I wrote about it here: https://revspace.nl/Space_invaders_repair Later I took a course in repairing Arcade systems in the Dutch national videogame computer museum in zoetermeer lead by the famous Randy Fromm https://revspace.nl/Arcade_repair_course		* I repaired a Space invaders console, space invaders was one of the first game consoles that used a CPU, an intel 8080, the same hardware was first used by a cowboy fighting game, but that wan't very successful, it was Space invaders that first took of (after Atari's pong of course, but pong didn't use a CPU) I wrote about it here: https://revspace.nl/Space_invaders_repair Later I took a course in repairing Arcade systems in the Dutch national videogame computer museum in zoetermeer lead by the famous Randy Fromm https://revspace.nl/Arcade_repair_course

	# although I gave a way almost all my retro computer stuff to musea, I still own a few systems, amon them are two CBM machines (commodore PET's) I repaired one of them and wrote about it https://revspace.nl/Repair_PET2001_AKA_CMB_3032		* although I gave a way almost all my retro computer stuff to musea, I still own a few systems, amon them are two CBM machines (commodore PET's) I repaired one of them and wrote about it https://revspace.nl/Repair_PET2001_AKA_CMB_3032

	# I saw a possibility to built a working game system built into my own joypad, with a simple wire connected to a minimal "game system", that really only consisted of power, video and sound connector. It is based on the Raspberry PI zero computer. I found a way to directly connect pushbuttons to it, that with some software were converted to keyboard input that Retropie could use, and also found a way to create sound output (in stereo) using the standard GPIO's (a zero doesn't have audio outputs normall). using these ideas I built up a simple prototype on perfboard that worked perfectly, having good PAL composite output, and stereo sound. I decided to design a (series of) PCB's for it using KiCAD, and wrote about it here: https://revspace.nl/The_worlds_smallest_(S)NES_emulator		* I saw a possibility to built a working game system built into my own joypad, with a simple wire connected to a minimal "game system", that really only consisted of power, video and sound connector. It is based on the Raspberry PI zero computer. I found a way to directly connect pushbuttons to it, that with some software were converted to keyboard input that Retropie could use, and also found a way to create sound output (in stereo) using the standard GPIO's (a zero doesn't have audio outputs normall). using these ideas I built up a simple prototype on perfboard that worked perfectly, having good PAL composite output, and stereo sound. I decided to design a (series of) PCB's for it using KiCAD, and wrote about it here: https://revspace.nl/The_worlds_smallest_(S)NES_emulator

	# I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.		* I was informed that a German ZX-81 fan had built my ZX81+35 clone, but he has also built my programmable sound chip (PSG) board, and understood I had tried to fix the problem that kept the GPIO's problem of only being able to turn all its 8 GPIO's all eight of them to either inputs or outputs as a unit, not for each GPIO pin, as a limitation that prevented it to generate an SPI signal using the AY-3-8912 GPIO's.
	# This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit.		* This was a problem as turning the GPIO's to inputs the SD-card I/O would be deselected. But he solved that simply by inverting the chip select line. And he added a bidirectional level converter on the data bit.
	It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone		* It took him two years (on and off obviously) to write an SPI bit banged driver, and used it to read files from a FAT-16 partition on the SD-Card, then used a menu driven interface so you could start any of 26 games on the card by pressing a single letter from A to Z. The firmware to do al this was stored on an 8K eprom extension (using a 16K flash ROM. I decided to update the ZX-81+35 and the PSG expansion so anyone could have the same functionality. You can read about it here: https://revspace.nl/Zon_ZX-81_Programmable_Sound_Generator_expansion_for_ZX81PLUS35_with_working_SD-Card and here: https://revspace.nl/ZX81PLUS35_ZX81_clone

	# I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it here: https://revspace.nl/Zon_ZX-81_compatible_PSG_%2B_32K_RAM_and_SD-Card_interface_expansion_for_ZX-81_and_clones		* I'm planning to also create my PSG board for the real ZX81 (and my own clone the ZX81+38)I wrote about it here: https://revspace.nl/Zon_ZX-81_compatible_PSG_%2B_32K_RAM_and_SD-Card_interface_expansion_for_ZX-81_and_clones

	If you want to contact me directly, you can send mail to mahjongg@xs4all.nl		If you want to contact me directly, you can send mail to mahjongg@xs4all.nl