Full-size SD card holder on the CGCOLORMAX2.
D4 – Green “Power/Firmware” LED, left of SD card holder.
D5 – Blue SD card access LED on the right of the SD card holder.
Audio/PWM header.
J8 – Stereo audio (PWM) out. Pin1 is PWM1, pin2 is PWM2, pin3 is ground.
J16 (1×6) / J17 (2×3 pattern next to J16, no silk screen label) are PIC32 programming headers.
J18 – extra connections for PS/2 keyboard.
J18 – 1×4 extra keyboard header. A PS/2 keyboard circuit (the CGKEYCHIP1, for example) can be wired to this extra connector.
|
J18-1 |
PS/2 clock |
|
J18-2 |
Ground |
|
J18-3 |
PS/2 data |
|
J18-4 |
+5V |
J19 – I2C lines for system (RTC) use. J19-1 is SDA, J19-2 is SCL.
J20 – This header is in parallel with the RTC battery if you choose to not use the coin cell but instead use an external clock battery. J20- 1 is positive. J20-2 is ground. The replacement coin cell is a CR2016.
J21 – This is in parallel with the “Power/Firmware” LED and resistor circuit. You can control the LED via MMBasic commands and this connection will let you control an external circuit in parallel with the LED.
There are connections to ground, +5V, and +3.3V in the “sea-of-holes” prototype area for connecting the custom circuits to power.
A bootloader wire jumper in place on a CGCOLORMAX2.
J7 – A jumper in place is for firmware reload. The two connections can be temporarily shorted together with a short piece of solid wire while applying USB power to the board to put the board on bootloader mode.
In the new version that you send me, the audio has two more pins audio1 & audio2.
Can you give some more info on those please?
The PWM lines (PWM1, PWM2) are the digital lines directly from the processor. The AUDIO lines (AUDIO1, AUDIO2) are after a low pass filter to remove the higher switching frequencies of the PWM. You would use the AUDIO lines for sound. AUDIO1 is left, AUDIO2 is right.
yes I have a new board with the same 5 pins. Ok I understand connect AUDIO1, and AUDIO2. Most likely ground too. But can you recommend a audio connector that might solder in here, or should I just strip a 3.5mm extension cable and solder the bare wires directly?
You could solder wires directly or use a board that has a jack on it.
https://www.ebay.com/itm/TRRS-3-5mm-Jack-Breakout-Audio-Stereo-Headphon-Microphone-Interface-Module-ESCA/232841672459
Do the audio pins provide good sound as-is or is an amplifier necessary?
Could I use piezo speakers with the audio pins?
The connections can’t drive a speaker directly. They are considered “line level” and will need to be amplified. A piezo connected directly would have very low, if any, sound output.