Combination Switch Reading Function

Description

BCM reads the status of the combination switch at 10 ms interval normally.

Fig 1: Combination Switch Input And Output Patterns
Courtesy of NISSAN NORTH AMERICA, INC.

NOTE: BCM reads the status of the combination switch at 60 ms interval when BCM is controlled at low power consumption control mode.
BCM operates as follows and judges the status of the combination switch.
- It operates the transistor on OUTPUT side in the following order: OUTPUT 1 → 2 → 3 → 4 → 5, and outputs voltage waveform.
- The voltage waveform of OUTPUT corresponding to the formed circuit is input into the interface on INPUT side if any (1 or more) switches are ON.
- It reads this change of the voltage as the status signal of the combination switch.
  
  Fig 2: BCM Output And Input Voltage Waveform Graph
  Courtesy of NISSAN NORTH AMERICA, INC.
Operation Example

In the following operation example, the combination of the status signals of the combination switch is replaced as follows: INPUT 1 - 5 to "1 - 5" and OUTPUT 1 - 5 to "A - E".

Example 1: When a switch (TAIL LAMP switch) is turned ON
The circuit between OUTPUT 4 and INPUT 5 is formed when the TAIL LAMP switch is turned ON.

Fig 3: Identifying Combination Switch Status Signal
Courtesy of NISSAN NORTH AMERICA, INC.
BCM detects the combination switch status signal "5D" when the signal of OUTPUT 4 is input to INPUT 5.
BCM judges that the TAIL LAMP switch is ON when the signal "5D" is detected.
Example 2: When some switches (TURN RH switch, TAIL LAMP switch) are turned ON
The circuits between OUTPUT 1 and INPUT 5 and between OUTPUT 4 and INPUT 5 are formed when the TURN RH switch and TAIL LAMP switch are turned ON.

Fig 4: Combination Switch Status Signal (Tail Lamp Switch Turned ON)
Courtesy of NISSAN NORTH AMERICA, INC.
BCM detects the combination switch status signal "5AD" when the signals of OUTPUT 1 and OUTPUT 4 are input to INPUT 5.
BCM judges that the TURN RH switch and TAIL LAMP switch are ON when the signal "5AD" is detected.