ez80190 ZiLOG Semiconductor, ez80190 Datasheet - Page 46

• Manufacturer Part Number: ez80190
• Description: Ez80190 Microprocessor
• Manufacturer: ZiLOG Semiconductor

PS006613-0306
PRT Clock
PRT Count
Value
(CLK/2)
IOWRN
Interrupt
Request
CLK
Programmable Reload Timer Operation
Setting Timer Duration
There are three factors to consider when determining Programmable Reload
Timer duration—clock frequency, clock divider ratio, and initial count value. Mini-
mum duration of the timer is achieved by loading
out on the next clock edge. Maximum duration is achieved by loading
because the timer rolls over to
counting down to
The time-out period of the PRT is returned by the following equation:
SINGLE PASS Mode
In SINGLE PASS mode, when the end-of-count value,
ing halts, the timer is disabled, and the PRT_EN bit resets to 0. To restart the
timer, the CPU must reenable the timer by setting the PRT_EN bit to 1. An exam-
ple of a PRT operating in SINGLE PASS mode is illustrated in
ister information is indicated in
PRT Time-Out Period =
x
Figure 4. PRT SINGLE PASS Mode Operation Example
I/O Write to TMRx_CTL
0000h
4
Enables PRT
.
PRELIMINARY
FFFFh
3
Clock Divider Ratio x Reload Value
Table
System Clock Frequency
3.
on the next clock edge and then continues
2
eZ80190 Product Specification
0001h
1
0000h
, because the timer times
Programmable Reload Timers
, is reached, count-
Figure
0
4. Timer reg-
0000h
,
32