P9242-R3/RB Datasheet

© 2019 Integrated Device Technology, Inc.

27

May 17, 2019

After confirming that the new data is available to be read, the external MCU should read register 080FHEX, which indicates the number of

incoming data bytes received. Based on the information, the MCU on transmitter should read the number of bytes indicated from user incoming

data registers 0810HEX to 0817HEX. For example, if the external MCU on the transmitter receives 3 bytes of information, register 080FHEX will

indicate 38HEX; therefore the external MCU on the transmitter should read only registers 0810HEX to 0812HEX (3 bytes) and ignore 0813HEX to

0817HEX.

Table 11. Registers Used for Reading User Data from the P9242-R3

Register Name

Register Address

Data Received Status

0801HEX

Clear Interrupt

0803HEX

Incoming Data Header

080FHEX

Incoming User Data

0810HEX to 0817HEX

After reading the data, the external MCU on the transmitter should clear the interrupt by writing 01HEX to register 0803 HEX. If the external MCU

on the transmitter does not handle interrupts, it should constantly poll the data received flag to check whether there is any new incoming data.

If the external MCU on the transmitter does not read data immediately after the interrupt is received, there is a risk that data could become

corrupted because of new incoming data. The 9242-R3 does not reject new incoming data because the old data was not read by the MCU on

the transmitter. The user can implement a higher level handshaking protocol between the external MCU on transmitter and receiver to avoid

data corruption.

Figure 28. State Diagram for Reading Data Sent from the P9221-R3

Read register 080FHEX, which

indicates the number of user data

bytes received. Read incoming user

data registers accordingly

(0810HEX to 0817HEX)

Yes

Did INT pin

transition from

HIGH to LOW and is

bit 0 of register 0801HEX

set to “1”?

Set bit 0 of register 0803HEX to “1”

to clear the received data flag and

reset the INT pin