RDAIRPABPSI5UG , Rev. 2.0
16
Freescale Semiconductor, Inc.
Describing the Device Functions
5.1.8
DC Sensors
The firmware must select which DC sensor is active and which supply voltage is used on that sensor through the DCS_CONTROL register.
The firmware must also select the correct sensor to be read through the analog output pin using the AI_CONTROL register. Note that both
registers can be returned to their default state by a correct write to the DIAG_CLR register.
5.1.9
PSI5 Satellite Sensor Interface
The firmware must select the correct mode of operation of the satellite sensor interface and enable each interface individually. The
interfaces should be enabled one at a time to reduce current inrush.
When the interface is enabled, the satellite sensor will automatically send its initialization data, and the firmware must handle this data to
ensure the sensor is operating correctly.
5.1.9.1
LIN Physical Layer
The firmware has the potential to change the configuration of the LIN physical layer, but the default setting is the most common
configuration.
A special mode exists which allows the Manchester encoded data from a satellite sensor to be monitored on the LIN RXD output pin, for
example in case MCU has a PSI5 peripheral module embedded.
5.1.9.2
Lamp Driver
The firmware must configure whether the driver is a high or low-side switch, and the PWM output duty cycle. In the response to the
command, the firmware can check that high or low thresholds on the pins have been exceeded, and whether an over-temperature
shutdown has occurred.
As part of the application, the warning lamp should be turned on at key on, kept illuminated until the startup diagnostic procedure has
completed, and the system is ready to start operating.
Table 12. DC Sensors
Define
Function
Config Register
Diagnosis
Comment
MC33789
Seat belt/Seat track
sensor interface
DCS_CONTROL,
AI_CONTROL
–
Table 13. PSI5 Satellite Sensor Interface
Define
Function
Config Register
Diagnosis
Comment
MC33789
Satellite Sensor
LINE_MODE,
LINE_ENABLE
–
Table 14. LIN Physical Layer
Define
Function
Config Register
Diagnosis
Comment
MC33789
LIN physical layer
LIN_CONFIG
–
Table 15. Lamp Driver
Define
Function
Config Register
Diagnosis
Comment
MC33789
Lamp driver
GPOn_CTL
GPOn_CTL
