Espressif ESP32 Technical Reference Manual page 56

4 IO_MUX and GPIO Matrix (GPIO, IO_MUX)
VDDA
LNA_IN
VDD3P3
VDD3P3
SENSOR_VP
SENSOR_CAPP
SENSOR_CAPN
SENSOR_VN
CHIP_PU
VDET_1
VDET_2
32K_XP
32K_XN
GPIO25
Figure 4-5. ESP32 I/O Pad Power Sources (QFN 5*5, Top View)
• Pads marked blue are RTC pads that have their individual analog function and can also act as normal digital
IO pads. For details, please see Section 4.11.
• Pads marked yellow and green have digital functions only.
• Pads marked green can be powered externally or internally via VDD_SDIO (see below).
4.8.1 VDD_SDIO Power Domain
VDD_SDIO can source or sink current, allowing this power domain to be powered externally or internally. To
power VDD_SDIO externally, apply the same power supply of VDD3P3_RTC to the VDD_SDIO pad.
Without an external power supply, the internal regulator will supply VDD_SDIO. The VDD_SDIO voltage can be
configured to be either 1.8V or the same as VDD3P3_RTC, depending on the state of the MTDI pad at reset –
a high level configures 1.8V and a low level configures the voltage to be the same as VDD3P3_RTC. Setting the
efuse bit determines the default voltage of the VDD_SDIO. In addition, software can change the voltage of the
VDD_SDIO by configuring register bits.
4.9 Peripheral Signal List
Table 4-2 contains a list of Peripheral Input/Output signals used by the GPIO Matrix:
Signal Input Signal
0 SPICLK_in
1 SPIQ_in
Espressif Systems
1
2
3
4
5
6
7
ESP32
49 GND
8
9
10
11
12
13
14
Table 4-2. GPIO Matrix Peripheral Signals
Output Signal
SPICLK_out
SPIQ_out
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38 GPIO19
37 VDD3P3_CPU
36 GPIO23
35 GPIO18
34 GPIO5
33 SD_DATA_1
32 SD_DATA_0
31 SD_CLK
30 SD_CMD
29 SD_DATA_3
28 SD_DATA_2
27 GPIO17
26 VDD_SDIO
25 GPIO16
56
Analog pads
Pads powered by VDD3P3_CPU
Pads powered by VDD_SDIO
Pads powered by VDD3P3_RTC
Direct I/O in IO_MUX
YES
YES
ESP32 TRM (Version 5.2)