LNBH24 STMicroelectronics, LNBH24 Datasheet - Page 14

• Manufacturer Part Number: LNBH24
• Description: Dual LNB supply and control IC with step-up and I2C interface
• Manufacturer: STMicroelectronics

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6.1
6.2
6.3
6.4
6.5
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I²C bus interface
Data transmission from main MCU to the LNBH24 and vice-versa takes place through the 2
wires I²C bus Interface, consisting of the 2 SDA and SCL lines (pull-up resistors to positive
supply voltage must be externally connected).
Data validity
As shown in
the clock. The HIGH and LOW state of the data line can only change when the clock signal
on the SCL line is LOW.
Start and stop condition
As shown in
SCL is HIGH. The stop condition is a LOW to HIGH transition of the SDA line while SCL is
HIGH. A STOP condition must be sent before each START condition.
Byte format
Every byte transferred to the SDA line must contain 8 bits. Each byte must be followed by an
acknowledge bit. The MSB is transferred first.
Acknowledge
The master (MCU) puts a resistive HIGH level on the SDA line during the acknowledge clock
pulse (see
the SDA line during the acknowledge clock pulse, so that the SDA line is stable LOW during
this clock pulse. The peripheral which has been addressed has to generate acknowledge
after the reception of each byte, otherwise the SDA line remains at the HIGH level during the
ninth clock pulse time. In this case the master transmitter can generate the STOP
information in order to abort the transfer. The LNBH24 will not generate acknowledge if the
V
Transmission without acknowledge
Avoiding to detect the acknowledges of the LNBH24, the MCU can use a simpler
transmission: simply it waits one clock without checking the slave acknowledging, and sends
the new data. This approach of course is less protected from malfunctions and decreases
the noise immunity.
CC
supply is below the under-voltage lockout threshold (6.7 V typ.).
Figure
Figure 5
Figure 6
7). The peripheral (LNBH24) that acknowledges has to pull-down (LOW)
the data on the SDA line must be stable during the high semi-period of
a start condition is a HIGH to LOW transition of the SDA line while