Tanmatsu: external add-on port

The external expansion port (CATT, for “Connect All The Things”) on Tanmatsu has been designed to be compatible with both PMOD and SAO add-on boards, in addition to it being a port that exposes 8 GPIOs and 3.3v power it can also be used as JTAG interface for the ESP32-P4.

Pinout

PinFunctionCATT namePMOD nameSAO nameJTAG nameGPIODescriptionNotes
1Power out+3.3v-+3.3v+3.3v-3.3v output
2Power outGND-GNDGND-Ground
3GPIOI2C SDAIO8SDA-12GPIO or I2C dataUsed as I2C bus for automatic add-on detection
4GPIOI2C SCLIO1SCL-13GPIO or I2C clockUsed as I2C bus for automatic add-on detection
5GPIOUSER AIO7IO1-15GPIO
6GPIOUSER BIO2IO2DETECT34GPIO, with special functionPull low on startup to switch to JTAG mode
7GPIOUSER CIO6-MTMS4GPIO or JTAG
8GPIOUSER DIO3-MTDO5GPIO or JTAG
9GPIOUSER EIO5-MTCK2GPIO or JTAG
10GPIOUSER FIO4-MTDI3GPIO or JTAG
11Power outGNDGND-GND-Ground
12Power outGNDGND-GND-Ground
13System resetP4 reset“3.3v”-P4 reset-Reset input for the ESP32-P4Can be converted to +3.3v output by shorting JP1 on the mainboard
14Power out+3.3v-+3.3v-3.3v output

connector

Limitations, warnings and hints

  • Total for all 3.3v outputs must not exceed 1A of current. It is generally adviced to stay well below this figure.
  • Detect pin has a pull-up resistor connected, pull low to enable JTAG functionality for the ESP32-P4
  • You can short jumper JP1 to connect pin 13 to the +3.3v rail
  • Even if JTAG functioality is selected you can simply initialize a pin as GPIO to use it as such
  • If you want to use JTAG via the USB-C port you will need to set the JTAG source manually in software if pin 6 (GPIO34) is being pulled low by an add-on board