Lucent Technologies MN102H75K User Manual
Timers
16-Bit Timer Setup Examples
Panasonic Semiconductor Development Company
MN102H75K/F75K/85K/F85K LSI User Manual
94
Panasonic
4.11 16-Bit Timer Setup Examples
4.11.1 Setting Up an Event Counter Using Timer 4
In this example, timer 4 counts the TM4IB input signal (B
OSC
/4 = 6 MHz or less)
and generates an interrupt on the second and fifth cycles.
■
To set up timer 4:
Use the MOV instruction for this
setup and only use 16-bit write
operations.
operations.
This step stops the TM4BC
count and clears both TM4BC
and the S-R flip-flop to 0.
1.
Set the operating mode in the timer 4 mode register (TM4MD). Disable
timer 4 counting and interrupts. Select up counting. Select TM4IB as the
clock source.
clock source.
TM4MD (example)
x’00FE80’
2.
Set the divide-by ratio for timer 4. To divide the TM4IB input signal by 5,
write x’0004’ to timer 4 compare/capture register A (TM4CA). (The valid
write x’0004’ to timer 4 compare/capture register A (TM4CA). (The valid
range for TM4CA is x’0001’ to x’FFFE’.)
A. Chip Level
B. Block Level
Figure 4-27 Block Diagram of Event Counter Using Timer 4
TM4IB
P2
P6
P4
P5
CORE
Interrupts
Timers 0-3
Timers 4-5
ROM, RAM
Bus Controller
Serial I/Fs
ADC
(B
OSC
/4)
up
TM4BC
Timer 4
TM4CA
TM4CAX
TM4CB
TM4CBX
TM4IB
(TM4OA)
T
Q
T
Q
R
S
S
Q
Controller
Bit:
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TM4
EN
TM4
NLD
NLD
—
—
TM4
UD1
UD1
TM4
UD0
UD0
TM4
TGE
TGE
TM4
ONE
ONE
TM4
MD1
MD1
TM4
MD0
TM4
ECLR
TM4
LP
TM4
ASEL
TM4
S2
TM4
S1
TM4
S0
Setting:
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0