While ordering components for a mini C64 project I’m doing with my friend Bigred, I ordered a cheap ST7789-v2 display.
I want to make a generic pico gadget with a display, buttons and sound.
This to make a mini device for writing micropython demos.
The 3 tactical buttons are controlling the X,Y and Z axis of the rotating Cube.
Pinout:
| PICO | DISPLAY |
| GP2 | Tactical switch (other side to 3v3) |
| GP3 | Tactical switch (other side to 3v3) |
| GP4 | Tactical switch (other side to 3v3) |
| GP9 | CS1 |
| GND | GND |
| 3v3 | VCC |
| GP18 | SCL (SPI clock) |
| GP19 | SDA (MOSI / SPI Data) |
| GP20 | RES (reset) |
| GP17 | DC (data command) |
| GP16 | BLK (backlight) |
I know it says SCL/SDA (i2c) but it’s SPI controlled.
Used library : https://github.com/russhughes/st7789_mpy/tree/master
Some 3D explanation I drew a long time ago.
Using python you can use the Math funtions. (sin/cos)
Note: these are in radians!
print(math.sin(math.radians(30))) # 30 degrees
When using MachineCode you can use lookup tables.
These are generated tables which hold precalculated sin data for every degree.
You don’t have to use both cos and sin! (these are just 90 degrees shifted!)
Erik and I used a little basic program to generate an ASM include file like this
Costab LABEL BYTE DB 0B4h,0B4h,0B4h,0B4h,0B4h,0B3h,0B3h,0B3h,0B2h,0B2h,0B1h,0B1h,0B0h,0AFh,0AFh DB 0AEh DB 0ADh,0ACh,0ABh,0AAh,0A9h,0A8h,0A7h,0A6h,0A5h,0A4h,0A2h,0A1h,0A0h,9Eh,9Dh,9Bh DB 9Ah,98h,96h,95h,93h,91h,90h,8Eh,8Ch,8Ah,88h,86h,84h,82h,80h,7Eh DB 7Ch,7Ah,78h,76h,74h,72h,70h,6Eh,6Ch,69h,67h,65h,63h,61h,5Eh,5Ch DB 5Ah,58h,56h,53h,51h,4Fh,4Dh,4Bh,48h,46h,44h,42h,40h,3Eh,3Ch,3Ah DB 38h,36h,34h,32h,30h,2Eh,2Ch,2Ah,28h,26h,24h,23h,21h,1Fh,1Eh,1Ch DB 1Ah,19h,17h,16h,14h,13h,12h,10h,0Fh,0Eh,0Dh,0Ch,0Bh,0Ah,09h,08h DB 07h,06h,05h,05h,04h,03h,03h,02h,02h,01h,01h,01h,00h,00h,00h,00h DB 00h,00h,00h,00h,00h,01h,01h,01h,02h,02h,03h,03h,04h,05h,05h,06h DB 07h,08h,09h,0Ah,0Bh,0Ch,0Dh,0Eh,0Fh,10h,12h,13h,14h,16h,17h,19h DB 1Ah,1Ch,1Eh,1Fh,21h,23h,24h,26h,28h,2Ah,2Ch,2Eh,30h,32h,34h,36h DB 38h,3Ah,3Ch,3Eh,40h,42h,44h,46h,48h,4Bh,4Dh,4Fh,51h,53h,56h,58h DB 5Ah,5Ch,5Eh,61h,63h,65h,67h,69h,6Ch,6Eh,70h,72h,74h,76h,78h,7Ah DB 7Ch,7Eh,80h,82h,84h,86h,88h,8Ah,8Ch,8Eh,90h,91h,93h,95h,96h,98h DB 9Ah,9Bh,9Dh,9Eh,0A0h,0A1h,0A2h,0A4h,0A5h,0A6h,0A7h,0A8h,0A9h,0AAh,0ABh,0ACh DB 0ADh,0AEh,0AFh,0AFh,0B0h,0B1h,0B1h,0B2h,0B2h,0B3h,0B3h,0B3h,0B4h,0B4h,0B4h CosTabE LABEL BYTE Basic: 0 DEF SEG = &H7000: c = 0 1 pi = 3.14159265# 2 FOR x = 0 TO 2 * pi STEP 2 * pi / 256 3 d = COS(x) * 127 + 127 4 POKE c, d: c = c + 1: NEXT
Most i learned from a book called “Art of Graphics”
(This is image of the book from the internet, i don’t think I still got my copy somewhere.
