
APPLICATION
2.2 Timer
2-19
3802 GROUP USER’S MANUAL
Control procedure :
Figure 2.2.19 shows a control procedure.
Fig. 2.2.19 Control procedure [Measurement of frequency]
Timer 1 interrupt processing routine
RESET
IREQ1 (Address : 3C
16
), bit5
Initialization
.
TM
PRE12
T1
PREY
TY
I.
TM
.
CLI
(Address : 23
16
)
(Address : 20
16
)
(Address : 21
16
)
(Address : 26
16
)
(Address : 27
16
)
(Address : 3E
16
), bit6
(Address : 23
16
), bit7
1110
XXXX
2
64–1
8–1
1–1
256–1
1
~
(A) TY (Address : 27
16
)
TY
IREQ1
(Address : 27
16
)
(Address : 3C
16
), bit5
256 – 1
0
1
0
Fpulse 0
Fpulse 1
Processing for a result of judgment
RTI
Out of range
In range
Compare the count value read with the
reference value.
Store the comparison result in flag Fpulse.
G
G
CLT (
Note 1
)
CLD (
Note 2
)
Push register to stack
Note 1:
When using the Index X mode flag (T).
Note 2:
When using the Decimal mode flag (D).
G
Push the register used in the interrupt
processing routine into the stack.
Pop registers
X
G
Set it to “0” or “1.” It’s value can be disregarded.
:This bit is not used in this application.
0
G
G
Read the count value.
Store the count value in the accumulator (A).
G
G
Initialize the count value.
Set the Timer Y interrupt request bit to “0.”
G
When the count value is 256 or more, the
processing is performed as out of range.
G
G
G
G
All interrupts : Disabled
Timer Y : Event counter mode
(Count at falling edge of pulse input from CNTR
1
pin)
Set the division ratio so that the Timer 1 interrupt
occurs every 2 ms.
Timer 1 interrupt : Enabled
G
Timer Y count : Start
Interrupts : Enabled
G
214 (A) 228
Pop registers which is pushed to stack.
G