Espressif ESP32 Technical Reference Manual page 673

30 ULP Coprocessor (ULP)
Operand Description - see Figure
Rdst Destination Register R[0-3], results will be stored in this register.
Sel Selected ADC: 0 = SAR ADC1, 1 = SAR ADC2, see Table 30-4.
Sar Mux SARADC Pad [Sar_Mux - 1] is enabled, see Table 30-4.
Table 30-4. Input Signals Measured Using the ADC Instruction
Description
The instruction prompts the taking of measurements with the use of ADC. Pads/signals available for ADC
measurement are provided in Table 30-4.
30.4.12 I2C_RD/I2C_WR – Read/Write I²C
31 28 27
4'd3
Operand Description - see Figure
Sub-addr Slave register address
Data Data to write in I2C_WR operation (not used in I2C_RD operation)
Low High part of bit mask
High Low part of bit mask
I2C Sel Select register
R/W I²C communication direction:
1 - I²C write
0 - I²C read
Espressif Systems
30-15
Pad Name/Signal/GPIO
SENSOR_VP (GPIO36)
SENSOR_CAPP (GPIO37)
SENSOR_CAPN (GPIO38)
SENSOR_VN (GPIO39)
32K_XP (GPIO33)
32K_XN (GPIO32)
VDET_1 (GPIO34)
VDET_2 (GPIO35)
GPIO4
GPIO0
GPIO2
MTDO (GPIO15)
MTCK (GPIO13)
MTDI (GPIO12)
MTMS (GPIO14)
GPIO27
GPIO25
GPIO26
25 22 21 19 18
High
Low
I2C Sel
Figure 30-16. Instruction Type — I²C
30-16
n of SENS_I2C_SLAVE_ADDRn
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Sar_Mux Processed by /Sel
1
2
3
4
SAR ADC1/Sel = 0
5
6
7
8
1
2
3
4
5
SAR ADC2/Sel = 1
6
7
8
9
10
16 15 8
Data
(n: 0-7), which contains the I²C slave address.
673
7 0
Sub-addr
ESP32 TRM (Version 5.2)