MC68HC901P MOTOROLA [Motorola, Inc], MC68HC901P Datasheet - Page 42

• Manufacturer Part Number: MC68HC901P
• Description: Multi-Function Peripheral
• Manufacturer: MOTOROLA [Motorola, Inc]

Timers
Bits 7-5 — *Unused
Unused bits read as zero.
Reset TAO/TBO — Reset Timer A and B Output
TAO and TBO may be forced low at any time by writing a one to the reset location in TACR
and TBCR. Output is held low during the write operation, and at the end of the bus cycle the
output is allowed to toggle in response to a time-out pulse. When resetting TAO and TBO,
the other bits in the TCR must be written with their previous value to avoid altering the
operating mode.
AC3-AC0/BC3-BC0 — Select Timer A and B Operation Mode
When the timer is stopped, counting is inhibited. The contents of the timer’s main counter
are not affected, although any residual count in the prescaler is lost.
6-5
TACR REGISTER
TBCR REGISTER
RESET
RESET
FIELD
FIELD
ADDR
ADDR
BIT
BIT
AC3
BC3
0
0
0
0
0
0
0
0
1
7
0
7
0
*
*
AC2
BC2
0
0
0
0
1
1
1
1
0
6
0
6
0
*
*
AC1
BC1
0
0
1
1
0
0
1
1
0
MC68HC901 USER’S MANUAL
5
5
0
0
*
*
AC0
BC0
0
1
0
1
0
1
0
1
0
RESET
RESET
TAO
TBO
4
4
0
0
Timer Stopped
Delay Mode,
Delay Mode,
Delay Mode,
Delay Mode,
Delay Mode,
Delay Mode,
Delay Mode,
Event Count Mode
$1B
$19
AC3
BC3
3
0
3
0
4 Prescaler
10 Prescaler
16 Prescaler
50 Prescaler
64 Prescaler
100 Prescaler
200 Prescaler
OPERATION MODE
AC2
BC2
2
0
2
0
AC1
BC1
1
0
1
0
MOTOROLA
AC0
BC0
0
0
0
0