MC68HC05V12 Datasheet, PDF (179/246 Pages) Freescale Semiconductor, Inc – HCMOS Microcontreller Unit

Freescale Semiconductor, Inc.
Byte Data Link Controller – Digital (BDLC–D)
Low-Power Modes
A subsequent passive-to-active transition on the J1850 bus will cause
the BDLC to wake up and generate a non-maskable CPU interrupt
request. When a STOP instruction is used to put the BDLC in stop mode,
the BDLC is not guaranteed to correctly receive the message which
woke it up, since it may take some time for the BDLC internal operating
clocks to restart and stabilize. If a WAIT instruction is used to put the
BDLC in stop mode, the BDLC is guaranteed to correctly receive the
byte which woke it up, if and only if an end-of-frame (EOF) has been
detected prior to issuing the WAIT instruction by the CPU. Otherwise,
the BDLC will not correctly receive the byte that woke it up.
If this mode is entered while the BDLC is receiving a message, the first
subsequent received edge will cause the BDLC to wake up immediately,
generate a CPU interrupt request, and wait for the BDLC internal
operating clocks to restart and stabilize before normal communications
can resume. Therefore, the BDLC is not guaranteed to receive that
message correctly.
NOTE: Ensuring that all transmissions are complete or aborted prior to putting
the BDLC into stop mode is important.
MC68HC05V12 — Rev. 2.0
Byte Data Link Controller – Digital (BDLC–D)
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Technical Data