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fourstix / MCard1802TeensyPixieVideo

Teensy 3.2 based Pixie Video Simulator for the 1802 Membership Card
MIT License
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Add Support for SPI OLEDs #4

Open fourstix opened 4 years ago

fourstix commented 4 years ago

There are enough digital pins available on the Teensy 3.2 to support SPI OLED displays.

Some of the pins need to be re-arranged to free up pins 10, 11, 12 and 13 for SPI. The CS output can be on any pin, but the conventional location for CS is pin 10.

Video_On would need to be moved from the LED pin 13, which is used for SCK in SPI. Even if it isn't on the built in LED pin anymore, Video_On is part of the external design, and should be moved to another pin.

fourstix commented 4 years ago

Since SDA and SCL are not required for SPI, pins 19 and 18 are available. We can move SCO and SC1 to these pins to free up pins 11 and 13.

Pin 10 is /Clear and can be moved to the unused pin 22, and pin 13 Video_On can be moved to the unused pin 23.

The new pin assignments can be: Pin 10 CS (SPI) Pin 11 DOUT (SPI) Pin 12 DIN (SPI) Pin 13 SCK (SPI)

Pin 18 SCO (was Pin 11) Pin 19 SC1 (was Pin 12)

Pin 22 /Clear (was Pin 10) Pin 23 Video_On (was Pin 13)

fourstix commented 4 years ago

Hmmm... Some SPI displays have an RST (Reset) and DC (Data/Command) inputs as well. So there needs to be 5 pins, not 4. Video_On may have to go. MISO (DIN) isn't used for displays, so maybe we can move /Clear to that pin.

Otherwise, we are out of pins and would have to use some of the digital IO pins available as pads on the bottom or use a Teensy 3.5 which is longer and has the additional data pins brought out.

fourstix commented 3 years ago

A Pixie Video simulator using a Teensy 3.2, SPI and a 4 wire GLCD was made for the Pico/Elf v2 microcomputer. It is available in the fourstix/PicoElfPixieVideoGLCD repository.