Freescale Semiconductor, Inc.
Bus Control and Input/Output
NDBE controls the use of the DBE pin of Port E. The NDBE bit has no
effect in Single Chip or Peripheral Modes. The associated pin will
default to the CAL function if the CALE bit is set in PEAR register or
otherwise to an I/O.
CGMTE — Clock Generator Module Testing Enable
Normal: write never; Special: write anytime EXCEPT the first. Read
anytime.
0 = PE6 is general-purpose I/O or pipe output.
1 = PE6 is a test signal output from the CGM module (no effect in
single chip or normal expanded modes). PIPOE = 1 overrides
this function and forces PE6 to be a pipe status output signal.
PIPOE — Pipe Status Signal Output Enable
Normal: write once; Special: write anytime EXCEPT the first time.
Read anytime.
0 = PE[6:5] are general-purpose I/O (if CGMTE = 1, PE6 is a test
output signal from the CGM module).
1 = PE[6:5] are outputs and indicate the state of the instruction
queue (only effective in expanded modes).
NECLK — No External E Clock
Normal single chip: write once; special single chip: write anytime; all
other modes: write never.
Read anytime. In peripheral mode, E is an input and in all other
modes, E is an output.
0 = PE4 is the external E-clock pin subject to the following
limitation: In single-chip modes, to get an E clock output signal,
it is necessary to have ESTR = 0 in addition to NECLK = 0. A
16-bit write to PEAR and MODE registers can configure all
three bits in one operation.
1 = PE4 is a general-purpose I/O pin.
Technical Data
MC68HC912DG128 — Rev 3.0
Bus Control and Input/Output
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