REV1.1 - major changes

A project log for MirkoPC -> CM4 carrier board

Yet another Raspberry Pi Computer (non-official carrier board for CM4).

MirkoMirko 04/30/2021 at 11:450 Comments

Main features and updates (compared to R1.0):
- new power button (slide switch) controlled by MCU (ATtiny),
- added 2 fan sockets (FAN #2 -> NPN transistor, FAN #3 -> EMC2301 controller),
- new microSD slot location (near to the PCB edge),
- improved 5V power rail (added extra vias, large capacitor),
- fixed USB-C issue (similar as on the Raspberry Pi 4B),
- removed eMMC BGA chip (due to collision with microSD),
- added slide switch for selecting USB mode (instead of 3-pin jumper J201),
- added solder jumpers for future disconnecting GPIO pins used for features as DAC, buzzer, status LEDs,
- new buzzer, smaller (without embedded generator),
- changed headphone amplifier with I2C bus and hardware volume control (TPA6130A2 instead TPA6133A2 due to IC shortage),
- replaced 3.3V/3A buck controller for M.2 socket (due to IC shortage),
- added ICT testopints,
- new silkscreen marking added,
- removed no needed pin headers (GLOBAL_EN and RUN_PG.

new slide switch for boot select:

new location of the microSD slot:

added ICT testopoints:

new power button (slide switch), controller by AVR attiny MCU:
improved 5V power rail (added large capacitor, removed polymer fuse, more vias added, copper track widen):