CAN Sampler
MPC5606S Microcontroller Reference Manual, Rev. 7
Freescale Semiconductor 181
Chapter 7
CAN Sampler
7.1 Introduction
The CAN Sampler peripheral has been designed to store the first identifier of CAN message detected on
the CAN bus while no precise clock (crystal) is running at that time on the device, typically in low-power
modes (Stop, Halt or Standby) or in Run mode with the crystal switched off.
Depending on both the CAN baud rate and which low-power mode is used, it is possible to catch either
the first or the second CAN frame by sampling one of two CAN Rx ports and storing all samples in internal
registers.
After selection of the mode (first or second frame), the CAN Sampler stores samples of the 48 bits or skips
the first frame and stores samples of the 48 bits of the second frame using the 16 MHz IRC oscillator and
the 5-bit clock prescaler.
After completion, software has to process the sampled data in order to rebuild the 48 minimal bits.
Figure 7-1. Extended CAN data frame
Base Identifier (11-bit)
SOF
SPR
Extended Identifier (18-bit)
IDE-bit
RTR-bit
r1
r0
Data
Length
Code
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