Data Sheet

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4. Peripheral Interface
4.3. Serial Peripheral Interface (SPI/HSPI)
ESP8266EX has 3 SPIs.
•
One general Slave/Master SPI
• One Slave SDIO/SPI
• One general Slave/Master HSPI
Functions of all these pins can be implemented via hardware. The pin definitions are
described as below.
4.3.1. General SPI (Master/Slave)
4.3.2. HSPI (Slave)
4.4. I2C Interface
ESP8266EX has one I2C used to connect with micro-controller and other peripheral
equipments such as sensors. The pin definition of I2C is as below.
Table 4-2. Pin Definitions of SPIs
Pin Name
Pin Num
IO
Function Name
SDIO_CLK
21
IO6
SPICLK
SDIO_DATA0
22
IO7
SPIQ/MISO
SDIO_DATA1
23
IO8
SPID/MOSI
SDIO_DATA_2
18
IO9
SPIHD
SDIO_DATA_3
19
IO10
SPIWP
U0TXD
26
IO1
SPICS1
GPIO0
15
IO0
SPICS2
📖 Note:
SPI mode can be implemented via software programming. The clock frequency is 80 MHz at maximum.
Table 4-3. Pin Definitions of HSPI (Slave)
Pin Name
Pin Num
IO
Function Name
MTMS
9
IO14
HSPICLK
MTDI
10
IO12
HSPIQ/MISO
MTCK
12
IO13
HSPID/MOSI
MTDO
13
IO15
HPSICS
Espressif
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2017.04