2. SYSTEM CONNECTOR INTERFACE
65
LZT 123 7263 R1C
2.15 External I 2C Serial Control Bus

Note! The I2C bus is currently not supported by the software

The external I2C bus consists of two signals, SDA and SCL. This bus

is isolated from the module’s internal I2C bus to ensure proper

operation of the module, even if the external I2C bus is damaged.

The electrical characteristics are shown below.

2.16 TX_ON - Burst Transmission

Burst transmission is the time when a GSM transceiver unit is

transmitting RF signals. TX_ON indicates the module is going into

transmission mode.

Pin Signal Dir Description
29 SDA I/O I2C serial data
30 SCL OI2C serial clock
Parameter Min. Typ. Max. Units
Transmit
operation
Frequency I2C CLK 81.25 400 kHz
High or low I2C CLK 1.2 µs
Delay time after falling edge of I2C
CLK
308 308-
1230
ns
Hold time after falling edge of I2C
CLK
0ns
Receive
operation
Frequency I2C CLK 400 kHz
High or low I2C CLK 1.2 µs
Delay time after falling edge of I2C
CLK
100 ns
Hold time after falling edge of I2C
CLK
0ns
Pin Signal Dir Description
35 TX_ON OGSM module to transmit