1   SD_Card_SPI_ISCP

SD card formated with FAT system serve for storing and reading files.

Currently it uses SPI and Arduino library, but as I use timers, I update millis() just each screen refresh to make illusion of time for its timeouts.

SPI have its LED and pinheader placed near SD card and may be separated by cutting solder jumpers (default connected). MISO/MOSI may serve also for PS/2 serial input when its (default open) solderjumpers are solrdered.

ISCP connector is also there with pin 1 marked by white rectangle under SD reader.

ISCP is ATmega/Arduino Standard and may be used for programming MCU. As there is not much space free, the Silkscreen is placed above (+5V GND), bellow (white mark visible from angle under SD card reader, Sck and Rst) and by sides (MISO left down, ISP right) for correct orientation of connector.

SD Card Reader may be cut out for freeing CS/SS PB0, or other pin may be used for SPI chip select.

SPI LED is connected to SCK and placed just above SD Card Reader near the SPI pinheader.

SD Card Reader should have level shift to 3V3 and fixed CS to disable MISO, when not active. See my comments here and original discussion.

(only resistor for LED visible here).

I tried classic Arduino SD library for reading SD card and it works, but need somehow advancing millis(), so I just incremented the value in VGA library. Also I tried only to read one byte at new screen, as I did not know the timing of the library, which was slow, but worked. I will make my own version with much better approach some time later (I hope).