I2C Bus - SimCom SIM800L Hardware Design

Whether using a 5*5 keys or 5*5*2 keys, the module can also detect the two buttons pressed. But when using a
5*5*2 button, the same row, column two buttons pressed at the same time can't be detected, as shown below:
Table 22: Pin definition of the keypad interface
Pin name Pin number
KBC0 20
KBC1 25
KBC2 22
KBC3 21
KBC4 24
KBR0 62
KBR1 60
KBR2 61
KBR3 23
KBR4 63
Note: Please be sure to increase the ESD protection devices in product design phase, and make sure have ESD protection devices
in the final product.

4.11. I2C Bus

The SIM800L provides an I2C interface which is only used in the embedded AT application.
SIM800L(MT6261)_Hardware Design_V1.01
KBCx
<1K
Module
KBRx
Figure 39: Keypad reference circuit
KBCx
Module
KBRx
Figure 40: Keypad detected
Function
Keypad matrix column
Keypad matrix row
Smart Machine Smart Decision
20K
20K
Default state
Pull up
Pull up
Pull up
Pull up
Pull up
Pull down
Pull down
Pull down
Pull down
Pull down
42 2016-07-07