Sim800 hardware design v1.05

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4.12. I2C BUS
The SIM800 provides an I2C interface, it can be driven by either the master or slave and conform to the I2C
specification. It has the following features:
z Compliant master mode operation
z Adjustable clock speed for LS/FS mode operation
z Support 7-bit/10-bit addressing
z Support high speed mode
z Support slave clock extension
z START/STOP/REPEATED condition
z Manual transfer mode
z Multi-write per transfer (up to 8 data bytes for non-DMA mode)
z Multi-read per transfer (up to 8 data bytes for non-DMA mode)
z Multi-transfer per transaction
z Combined format transfer with length change capability
z Active drive/write-and I/O configuration
Table 24: Pin definition of the I2C
Pin name Pin number Description
SCL 37 I2C serial bus clock
SDA 38 I2C serial bus data
Note: I2C has been pulled up to 2.8V via 4.7KΩ.
Table 25: I2C multiplex function
Pin name Pin number Mode 0(default) Mode 1
SCL 37 SCL GPIO24
SDA 38 SDA GPIO25
4.13. General Purpose Input/Output (GPIO)
SIM800 provides 2 GPIO pins. The output voltage level of the GPIO can be set by the AT command “AT+
SGPIO”. The input voltage level of the GPIO can also be read by the AT command “AT+ SGPIO”. For more
details, please refer to document [1].
Table 26: Pin definition of the GPIO
Pin name Pin number
Reset state
GPIO17
11 Pull down
GPIO19
13 Pull down
SIM800_Hardware Design_V1.05 47 2014-03-25