S908QC16CDRE FREESCALE [Freescale Semiconductor, Inc], S908QC16CDRE Datasheet - Page 151

• Manufacturer Part Number: S908QC16CDRE
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

13.9.4 Arbitration Mode
If AM[1:0] is set to 10, the arbiter module operates in arbitration mode. On every rising edge of SCI_TxD
(output of the transmit shift register, see ), the counter is started. When the counter reaches $38
(ACLK = 0) or $08 (ACLK = 1), RxD is statically sensed. If in this case, RxD is sensed low (for example,
another bus is driving the bus dominant) ALOST is set. As long as ALOST is set, the TxD pin is forced
to 1, resulting in a seized transmission.
If SCI_TxD senses 0 without having sensed a 0 before on RxD, the counter will be reset, arbitration
operation will be restarted after the next rising edge of SCI_TxD.
Freescale Semiconductor
RXD
RXD
Figure 13-21. Bit Time Measurement with ACLK = 1, Scenario A
Figure 13-22. Bit Time Measurement with ACLK = 1, Scenario B
MC68HC908QC16 • MC68HC908QC8 • MC68HC908QC4 Data Sheet, Rev. 2
MEASURED TIME
MEASURED TIME
ESCI Arbiter
151