sparkfun MicroMod ESP32 Hook-Up Manual page 7

If driven low, the boot messages printed by the ROM bootloader (at 115200 baud) are silenced. If unconnected or
driven high, the messages will be printed as they normally are. On the ESP32 MicroMod Processor, this pin is
connected to G0.
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I C
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We love us some I C! We've broken out two I C buses, which can be used with our Qwiic system. The main I C
bus has dedicated GPIO pins 21/22 connected to MicroMod pads 12/14, along with a dedicated interrupt pin
connected to GPIO pin 4, which is connected to pad 16 of the MicroMod connector.
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If you need a second I C bus, the ESP32 uses GPIO pins 25/26 (pads 42/44 on the MicroMod) for SCL1 and
SDA1.
Note: The secondary I C bus is shared with G1 and G2, as well as the I S bus pins for AUD_LRCLK and
AUD_BCLK.
UART
The ESP32 Processor has two UARTs available. The primary UART has dedicated GPIO pins 1 and 3 which can
be used for programming as well as printing debug messages to a terminal window. These GPIO pins aren't
directly broken out, but instead are converted to USB which is connected to MicroMod pads 3 and 5.
The second UART is connected GPIO pins 16 and 17 (pads 19 and 17 on the MicroMod) for RX1 and TX1.
Note: The secondary UART is shared with G3 and G4, as well as the I S bus pins for AUD_OUT, and
AUD_IN.
GPIO/BUS
The MicroMod connector supports a total of 12 general purpose IO pins, 7 of which are used on the ESP32
Processor, on top of the 6 dedicated pins. The dedicated pins are just that, and are not shared with any other pin,
unlike the general purpose pins which may be shared with other pins. The pins used are:
Dedicated Pins
A0 - GPIO pin 34, pad 34 on the MicroMod (Input Only!)
A1 - GPIO pin 35, pad 38 on the MicroMod (Input Only!)
D0 - GPIO pin 14, pad 10 on the MicroMod
D1 - GPIO pin 27, pad 18 on the MicroMod
PWM0 - GPIO pin 13, pad 32 on the MicroMod
PWM1 - GPIO pin 12, pad 47 on the MicroMod
General Purpose IO pins
G0 - GPIO pin 15, pad 40 on the MicroMod
G1 - GPIO pin 25, pad 42 on the MicroMod - Shared with the I S bus, and secondary I C bus.
G2 - GPIO pin 26, pad 44 on the MicroMod - Shared with the I S bus, and secondary I C bus.
G3 - GPIO pin 17, pad 46 on the MicroMod - Shared with the I S bus, and secondary UART.
G4 - GPIO pin 16, pad 48 on the MicroMod - Shared with the I S bus, and secondary UART.
G5 - GPIO pin 32, pad 73 on the MicroMod - Shared with the 32KHz RTC crystal.
G6 - GPIO pin 33, pad 71 on the MicroMod - Shared with the 32KHz RTC crystal.
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