FlexRay Communication Controller (FlexRay)MPC5644A Microcontroller Reference Manual, Rev. 61596 Freescale Semiconductor33.6.16 Strobe signal supportThe CC provides a number of strobe signals for observing internal protocol timing related signals in theprotocol engine. The signals are listed and described in Table 33-12.33.6.16.1 Strobe signal assignmentEach of the strobe signals listed in Table 33-12 can be assigned to one of the four strobe ports using theStrobe Signal Control Register (FR_STBSCR). To assign multiple strobe signals, the application mustwrite multiple times to the Strobe Signal Control Register (FR_STBSCR) with appropriate settings.To read out the current settings for a strobe signal with number N, the application must execute thefollowing sequence.1. Write to FR_STBSCR with WMD = 1 and SEL = N. (updates SEL field only)2. Read STBCSR.The SEL field provides N and the ENB and STBPSEL fields provides the settings for signal N.33.6.16.2 Strobe signal timingThis section provides detailed timing information of the strobe signals with respect to the protocol engineclock.The strobe signals display internal PE signals. Due to the internal architecture of the PE, some signals aregenerated several PE clock cycles before the actual action is performed on the FlexRay Bus. These signalsare listed in Table 33-12 with a negative clock offset. An example waveform is given in Figure 33-156.Figure 33-156. Strobe signal timing (type = pulse, clk_offset = -2)Other signals refer to events that occurred on the FlexRay Bus some cycles before the strobe signal ischanged. These signals are listed in Table 33-12 with a positive clock offset. An example waveform isgiven in Figure 33-157.Figure 33-157. Strobe signal timing (type = pulse, clk_offset = +4)PE ClockStrobe SignalFlexRay Bus Event-2PE ClockStrobe SignalFlexRay Bus Event+4
