Z8F1680SH020SG Datasheet, PDF (134/412 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F1680 Series
Product Specification
109
Bit
Field
Reset
R/W
Address
9.3.1. Timer 0–2 High and Low Byte Registers
The Timer 0–2 High and Low Byte (TxH and TxL) registers, shown in Tables 55 and 56,
contain the current 16-bit timer count value. When the timer is enabled, a read from TxH
causes the value in TxL to be stored in a temporary holding register. A read from TxL
always returns this temporary register when the timers are enabled. When the timer is
disabled, reading from the TxL reads the register directly.
Writing to the Timer High and Low Byte registers when the timer is enabled is not
recommended. There are no temporary holding registers available for write operations;
therefore simultaneous 16-bit writes are not possible. If either the Timer High or Low Byte
registers are written during counting, the 8-bit written value is placed in the counter (High
or Low Byte) at the next clock edge. The counter continues counting from the new value.
Table 55. Timer 0–2 High Byte Register (TxH)
7
6
5
4
3
2
1
0
TH
0
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
F00H, F08H, F10H
Table 56. Timer 0–2 Low Byte Register (TxL)
Bit
7
6
5
4
3
2
1
0
Field
TL
Reset
0
0
0
0
0
0
0
1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Address
F01H, F09H, F11H
Bit
[7:0]
TH, TL
Description
Timer High and Low Bytes
These 2 bytes, {TH[7:0], TL[7:0]}, contain the current 16-bit timer count value.
9.3.2. Timer Reload High and Low Byte Registers
The Timer 0–2 Reload High and Low Byte (TxRH and TxRL) registers, shown in
Tables 57 and 58, store a 16-bit reload value, {TRH[7:0], TRL[7:0]}. Values written to the
Timer Reload High Byte Register are stored in a temporary holding register. When a write
to the Timer Reload Low Byte Register occurs, this temporary holding register value is
written to the Timer High Byte Register. This operation allows simultaneous updates of
the 16-bit timer reload value.
PS025015-1212
PRELIMINARY
Timers