Firmware Functions
FXTH87xx11 and FXTH87xx12 Embedded Firmware User Guide, Rev. 2.1
Freescale Semiconductor, Inc.
35
3.2.32
UINT8 TPMS_MSG_WRITE(UINT8 u8SendByte)
•
Description:
This function is in charge to write a message at a network level via an emulated serial
interface on PTA1 and PTA0. As the master, the FXTH87xx11 and FXTH87xx12 manages the
clock on PTA1. On rising edge of the clock, the module puts down a new data bit on PTA0
(programmed as output), MSB first.
•
Stack size:
2 bytes
•
Approx. Duration:
80 usec
•
Power Management:
This function executes entirely in RUN mode.
•
Interrupt Management:
This function does not await any interrupts. It will not be affected by
interrupts.
•
Resources:
Pins PTA1 and PTA0.
•
Input Parameters:
— UINT8 u8SendByte: Byte to be outputted through the emulated serial interface.
•
Returns
:
— UINT8 u8ReadByte: Incoming byte from the emulated serial interface.
3.2.33
UINT8 TPMS_CHECKSUM_XOR(UINT8 *u8Buffer, UINT8 u8Size,
UINT8 u8Checksum)
•
Description:
Calculates a checksum for the given buffer based on XOR operations.
•
Stack size:
5 bytes
•
Approx. Duration:
80 usec for 8 bytes of data.
•
Power Management:
This function executes entirely in RUN mode.
•
Interrupt Management:
This function does not await any interrupts. It will not be affected by
interrupts.
•
Resources:
N/A
•
Input Parameters:
— UINT8 *u8Buffer: Buffer where data is located.
— UINT8 u8Size: Size of buffer (in bytes).
— UINT8 u8Checksum: Previous checksum. This argument is useful when the function is used
recursively. It must equal “0” if there is no previous data.
•
Returns
:
— UINT8 u8NewChecksum: New calculated checksum.
