Z86C72 Datasheet, PDF (35/71 Pages) Zilog, Inc. – IR MICROCONTROLLER

Zilog
CTR0 (D)00H: Counter/Timer8 Control Register.
Z86C72/C92/L72/L92
IR Microcontroller
Field
T8_Enable
Bit Position
7-------
Single/Modulo-N
Time_Out
-6------
--5-----
T8_Clock
---43---
Capture_INT_Mask
-----2--
Counter_INT_Mask
------1-
P34_Out
-------0
Note:
*Indicates the value upon Power-On Reset.
Value
Description
R
0*
Counter Disabled
1
1
Counter Enabled
W
0
Stop Counter
1
Enable Counter
R/W
0
Modulo-N
1
Single Pass
R
0
No Counter Time-Out
1
Counter Time-Out Occurred
W
0
No Effect
1
Reset Flag to 0
R/W
00
SCLK
01
SCLK/2
10
SCLK/4
11
SCLK/8
R/W
0
Disabled Data Capture Int.
1
Enable Data Capture Int.
R/W
0
Disable Data Capture Int.
1
Enable Time-Out Int.
R/W
0*
P34 as Port Output
1
T8 Output on P34
CTR0: Counter/Timer8 Control Register Description
T8 Enable. This field enables T8 when set (written) to 1.
Single/Modulo-N. When set to 0 (modulo-n), the counter
reloads the initial value when the terminal count is
reached. When set to 1 (single pass), the counter stops
when the terminal count is reached.
Time-Out. This bit is set when T8 times out (terminal count
reached). To reset this bit, a 1 should be written to this lo-
cation. This is the only way to reset this status condi-
tion, therefore, care should be taken to reset this bit
prior to using/enabling the counter/timers.
Note: Care must be taken when utilizing the OR or AND
commands to manipulate CTR0, bit 5 and CTR1, bits 0
and 1 (Demodulation Mode). These instructions use a
Read-Modify-Write sequence in which the current status
from the CTR0 and CTR1 registers will be ORed or ANDed
with the designated value and then written back into the
registers. Example: When the status of bit 5 is 1, a reset
condition will occur.
T8 Clock. Defines the frequency of the input signal to T8.
Capture_INT_Mask. Set this bit to allow interrupt when
data is captured into either LO8 or HI8 upon a positive or
negative edge detection in demodulation mode.
Counter_INT_Mask. Set this bit to allow interrupt when T8
has a time out.
P34_Out. This bit defines whether P34 is used as a normal
output pin or the T8 output.
DS97LVO0900
PRELIMINARY
6-35