PXD10RM Datasheet, PDF (171/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

6.5.6 Bootstrap with CAN
6.5.6.1 Configuration
Boot from FlexCAN protocol is implemented by the FlexCAN_0 module. The pins used are:
• CAN_TX corresponds to pin PB[0]
• CAN_RX corresponds to pin PB[1].
Boot from FlexCAN uses the system clock driven by an external oscillator.
The FlexCAN controller is configured to operate at a baud rate = system clock frequency/40 (see Table 6-6
for examples of baud rate).
It uses the standard 11-bit identifier format detailed in FlexCAN 2.0A specification.
FlexCAN controller bit timing is programmed with 10 time quanta, and the sample point is 2 time quanta
before the end, as shown in Figure 6-8.
NRZ Signal
SYNC_SEG
Time Segment 1
Time Segment 2
1
time quantum
7
time quanta
1 Bit Time
Transmit Point
1 time quantum = 4 system clock periods
Figure 6-8. FlexCAN Bit Timing
2
time quanta
Sample Point
Freescale Semiconductor
PXD10 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
6-13