MC68HC812A4 Datasheet, PDF (182/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

Standard Timer Module
Addr.
Register Name
Bit 7
6
5
4
3
2
1
Bit 0
Timer Port Data ^Read: _PT7
PT6
PT5
PT4
PT3
PT2
PT1
PT0
$00AE Register (PORTT) Write:
See page 206. _Reset:
Unaffected by reset
Timer Port Data Read:
$00AF
Direction Register
(DDRT)
Write:
Bit 7
5
5
4
3
2
1
Bit 0
See page 207. Reset: 0
0
0
0
0
0
0
0
= Unimplemented
R = Rserved
Figure 12-2. I/O Register Summary (Sheet 5 of 5)
NOTE: In normal modes, writing to a reserved bit has no effect and reading
returns logic 0.
In any mode, writing to an unimplemented bit has no effect and reading
returns a logic 0.
12.5 Functional Description
This section provides a functional description of the standard timer.
12.5.1 Prescaler
The prescaler divides the module clock by 1, 2, 4, 8, 16, 32, 64, or 128.
The prescaler select bits, PR2, PR1, and PR0, select the prescaler
divisor. PR2, PR1, and PR0 are in timer system control register 2
(TIMSCR2).
12.5.2 Input Capture
Clearing the I/O (input/output) select bit, IOSx, configures channel x as
an input capture channel. The input capture function captures the time
at which an external event occurs. When an active edge occurs on the
pin of an input capture channel, the timer transfers the value in the timer
counter into the timer channel registers, TIMCxH and TIMCxL.
MC68HC812A4 — Rev. 3.0
182
Standard Timer Module
Advance Information
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