Overview
The Compute Module IO Board Plus is a development board which you can plug a Raspberry Pi Compute Module into, and make use of the resources of Pi more flexibly. It is compatible with the Compute Module IO Board V3 from the Raspberry Pi Foundation, along with various common use components.

Compute Module IO Board Plus Features
1. Compatible with the Compute Module IO Board V3 from the Raspberry Pi Foundation
2. Raspberry Pi GPIO header, for connecting sorts of Raspberry Pi HATs
3. Arduino connectivity, also supports Arduino shields
4. 1-WIRE interface, for connecting single-bus devices like DS18B20
5. 4x keys, 4x LEDs, 1x Buzzer, for I/O testing
6. Onboard USB HUB, allows connecting more USB devices
7. IR receiver, IR remote control is available
8. Onboard USB TO UART, for serial debugging
9. Sensor interface
10. 10-bit ADC, 38KSPS, 11-ch (6-ch for Arduino interface, 5-ch for sensors)
11. 16-bit DAC, 2-ch
12. Onboard RTC, one of the most common and useful functions

What is on the Compute Module IO Board Plus
1. Compute Module interface: for connecting Compute Module (CM3 / CM3L / CM3+ / CM3+L)
2. Compute Module GPIO header: breakout all the Compute Module pins
3. Raspberry Pi GPIO header: for connecting Raspberry Pi HATs
4. CSI interface: camera ports, for connecting Raspberry Pi Camera
5. DSI interface: display ports, for connecting Raspberry Pi LCD
6. HDMI port
7. USB ports: for connecting USB devices
8. USB SLAVE interface: allows you to burn system image in to Compute Module 3
9. USB TO UART interface: for serial debugging
10. Arduino header: for connecting Arduino shields
11. AD/DA input/output screw terminals
12. 1-WIRE interface: for connecting single-bus devices like DS18B20
13. Sensor interface
14. Power port: 5V 2.5A
15. FE1.1S: USB HUB chip
16. 12MHz crystal
17. CP2102: USB TO UART converter
18. Micro SD card slot: Insert a Micro SD card with pre-burnt system, to start up Compute Module 3 Lite
19. TLC1543: AD converter
20. DAC8552: 16-bit DAC, 2-ch
21. DS3231: High-precision RTC chip, I2C interface
22. RTC battery holder: supports CR1220 batteries
23. Voltage regulator: 3.3V / 2.5V / 1.8V
24. LFN0038K: IR receiver
25. Buzzer
26. Power indicator
27. ACT indicator: indicating the Micro SD card status
28. User LEDs
29. User Keys
30. BOOT selection
- EN: enable the PC to access SD card/eMMC through USB SLAVE
- DIS: the Compute Module will boot from SD card/eMMC
31. VGx power selection: config the I/O level
32. USB HUB enable jumper: HUB enable and USB SLAVE power selection
33. ADC/DAC configuration: config the power supply and reference voltage of ADC/DAC
34. Peripheral configuration: config the control pins of UART, user keys, user LEDs, 1-WIRE interface, IR receiver, and buzzer
35. Arduino AD selection
- Connect 1 and 2: Arduino A0-A5 as digital control pin
- Connect 2 and 3: Arduino A0-A5 as AD input