mc68hc912d60c Freescale Semiconductor, Inc, mc68hc912d60c Datasheet - Page 294

• Manufacturer Part Number: mc68hc912d60c
• Description: Hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Freescale Interconnect Bus
16.5.1 Controller detected errors
16.5.2 MCU detected errors
16.6 Interfacing to MI Bus
Technical Data
294
There are three different MI Bus error types which are detected by the
selected slave device and are not mutually exclusive. The MCU cannot
determine which error occurred.
There is a fourth error that can be detected by the MCU. This error
causes the noise flag (NF) to be asserted in the SC0SR1 register during
the push field sequence.
Physically the MI Bus consists of only a single wire. In the example
shown in
components are required to connect up the MC68HC912D60A for full
MI Bus operation.
Noise error — Slave devices take two samples in each time slot of
the biphase encoded push field. An error occurs when the two
samples for each time slot are not the same logical level.
Biphase error — Slave devices receiving the push field detect the
biphase code. An error occurs when the two time slots of the biphase
code do not yield a logical exclusive-OR function.
Field error — A field error is detected when the fixed-form of the push
field is violated.
Bit error — A bit error can be detected by the MCU during the push
field. The MI Bus serial system monitors the bus via on-chip hardware
at the RxD0 pin at the same time as sending data. A bit error is
detected at that bit time when the value monitored is different from the
bit value sent.
Figure
Freescale Interconnect Bus
16-4, only a single transistor and a few passive
MC68HC912D60A — Rev. 3.1
Freescale Semiconductor