MC68HC812A4 Datasheet, PDF (202/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

Standard Timer Module
Use a double-byte read instruction to read the pulse accumulator
counter. Two single-byte reads return a different value than a
double-byte read.
NOTE:
Reading the pulse accumulator counter registers immediately after an
active edge on the PAI pin may miss the last count since the input has
to be synchronized with the bus clock first.
12.6.17 Timer Test Register
Address: $00AD
Bit 7
6
5
4
3
2
1
Read: 0
0
0
0
0
0
TCBYP
Write:
Reset: 0
0
0
0
0
0
0
= Unimplemented
Figure 12-24. Timer Test Register (TIMTST)
Bit 0
PCBYP
0
Read: Anytime
Write: Only in special mode (SMODN = 0)
TCBYP — Timer Divider Chain Bypass Bit
TCBYP divides the 16-bit free-running timer counter into two 8-bit
halves. The clock drives both halves directly and bypasses the timer
prescaler.
1 = Timer counter divided in half and prescaler bypassed
0 = Normal operation
PCBYP — Pulse Accumulator Divider Chain Bypass Bit
PCBYP divides the 16-bit PA counter into two 8-bit halves. The clock
drives both halves directly and bypasses the timer prescaler.
1 = PA counter divided in half and prescaler bypassed
0 = Normal operation
MC68HC812A4 — Rev. 3.0
202
Standard Timer Module
Advance Information
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