Retro Video Generator

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I found this project while I was experimenting with the NTSC Color video generator some time ago, but finally got round to ordering the parts I needed recently.

Thanks to Grant Searle for the awesome work on the project, which seems to have slipped into the recesses of the internet. This may be because unlike the classic 'TV_Out' for the Arduino, you need a programmer to upload the hex file directly to microcontroller.

The circuit uses a 74HCT166 parallel in/serial out shift register, clocked at the same 16MHz as an ATmega328P microcontroller, giving the speed necessary for a 640x200 pixel display.
The biggest problem I had was with the ATmega328P ICs I bought on Aliexpress. These seemed to have the option fuses set for a slow internal clock and it took a bit of messing about to get the fuses cleared so they could be set for the external crystal.

Best of all, data is input via a standard I2C 2-wire interface which will connect to PIC microcontrollers (which I have a box of!), finally giving me a flexible way to generate video for PIC-Jal projects.

I'm using the Avrdudess GUI to upload the hex files.

UPDATE 30/10/23


I followed Grant's instructions on how to modify his assembly code to hardwire the I2C option and change the device address. After a bit of fiddling with the Avra assembler, I got it working. Hardwiring the options saves a couple of components and a few lines of code and having multiple addresses means I will be able to drive 2 video generators on the I2C bus.

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