After reading the article Transmitting an analog TV signal using STM32, I decided to try to draw a TV signal on a cheap Chinese stm32f401ccu6 board for $ 2.5 without additional hardware.
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- - 1988 ZX spectrum 48 , . , -. , , - . / 5 PAL/NTSC, stm32f401ccu6 64B RAM ,256 Flash 84MHz 32bit processor.
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Specci 256 . 8 . 400 64 . (TIM1) 84MHz 13 , . 3, 10 , 1. Circular double buffer DMA . , 50 ( PAL). (TIM4), .
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, . , , USB.
Implementation of the Spectrum 128. There is a place for a flash on the board, so serial PSRAM (PSRAM64H 3.3V SOP8 64Mbit) fits and even works there, but only in 1Bit SPI mode because of the wiring on the board. About twice as slow as needed for emulation.
The TV is connected directly, but this is a violation of the signal level specification (3.3 instead of 1 volt). For good, you need a divider and a low-pass filter.
The video did not work out very well, the picture is really better, but it's difficult to shoot from TV: