Was wondering this for the CM4 as there are 40 pins, but I couldnt find any accesories thst go from flat serial to rpi type bigger pins. Also, while reading DevTerms forums, there was a lot of disappointing talk of how most of the pins are already taken by the custom clockwork board.
J3 - 40 pin FPC header
GPIO 0 - 27
all clockwork cards us pins 0-5, and 8-11 to control the power, headphones, backlight, etc.
the remainder of these pins, 6-7 and 12-27 are not connected on the CM4 module.
MINI_PCIE - Ext Module
GPIO 28 - 45, Camera Pins, 2x USB, Speaker L/R
all of these pins are connected to the CM4 and A06, but using them requires a custom ext module board that will expose them.
Note these pin numbers are the common clockworkpi notation, they don’t map 1:1 with the CM4 pins.
I made a table yesterday, but haven’t double checked it yet, the numbers i mention above are the SODIMM GPIO numbers.
| Pin/GPIO # | |||
|---|---|---|---|
| CM4 | SODIMM | Connection | Purpose |
| 2 | 2 | PMU_IRQ | Power |
| 3 | 3 | WL_REG_ON | Unused, to keep Wifi module off |
| 4 | 4 | WL_HOST_WAKE | Unused, to keep Wifi module off |
| 5 | 5 | BT_REG_ON | Unused, to keep BT module off |
| 6 | 38 | EXT MOD | |
| 7 | 39 | EXT MOD | |
| 8 | 8 | LCD_RESET | Display |
| 9 | 9 | BL_CTRL | Display |
| 10 | 10 | HP_DET | Audio |
| 11 | 11 | PA_EN | Audio |
| 12 | 12 | AUD_PWM0 | Audio |
| 13 | 13 | AUD_PWM1 | Audio |
| 14 | 32 | EXT MOD | |
| 15 | 33 | EXT MOD | 4g Module, RESET_MCU |
| 16 | 40 | EXT MOD | |
| 17 | 41 | EXT MOD | |
| 18 | 28 | EXT MOD | |
| 19 | 29 | EXT MOD | |
| 20 | 30 | EXT MOD | |
| 21 | 31 | EXT MOD | |
| 22 | IGPIO0 | PWR_ON | Power |
| 24 | 34 | EXT MOD | 4G Module, POWER_MCU |
| 25 | 35 | EXT MOD | |
| 26 | 36 | EXT MOD | |
| 27 | 37 | EXT MOD | |
| 28 | 43 | EXT MOD | |
| CAM_GPIO | 42 | EXT MOD | |
| ID_SC | 1 | PMU_SCK | Power |
| ID_SD | 0 | PMU_SDA | Power |
| SCL0 | 45 | EXT MOD | |
| SDA0 | 44 | EXT MOD |
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nice work! amazing detective work - I’m still leaning toward linking by wifi to external devices via esp32… although some in the group are designing an Ext module that will have more USB ports similar to the DevTerm.
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I wonder if you know whether any of the pads on the default expansion board are actually routed to pcie? I noted from the uPico schematics that SCL/SDA (I2C) seem to be on pins 50/52 of the mini pcie connector. I’m hoping those 52 pins are available on the pads (middle in the picture). Any ideas?
Also, that’s not PCIe, just a board-to-board connector using the same connector with mini PCIe…
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Ok, so the ‘default’ expansion board I have is an unpopulated 4G card. The schematic then assumes a SIM7600G-H in the middle? UART, speakers, SIM USB that’s all clear. From https://www.waveshare.com/w/upload/a/a0/SIM7600G-H_SPEC_EN_20190731.pdf it does look like it’s that layout. So, it could be ‘abused’.
Ah, found a layout: https://www.waveshare.com/w/upload/e/e6/SIM7600G_SIM7600G-H_Hardware_Design_V1.00.pdf page 11