deveopmen
Timer A
Preliminary Specifications REV.B
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M16C/80 (144-pin version) group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
99
Item
Specification
Count source
Count operation
f
1
, f
8
, f
32
, f
C32
The timer counts down
When the count reaches 0000
16
, the timer stops counting after reloading a
new count
If a trigger occurs when counting, the timer reloads a new count and restarts counting
1/n n : Set value
An external trigger is input
The timer overflows
The one-shot start flag is set (= 1)
A new count is reloaded after the count has reached 0000
16
The count start flag is reset (= 0)
Interrupt request generation timing
The count reaches 0000
16
TAi
IN
pin function
Programmable I/O port or trigger input
TAi
OUT
pin function
Programmable I/O port or pulse output (Setting by corresponding port function
select register and peripheral function select register)
Read from timer
When timer Ai register is read, it indicates an indeterminate value
Write to timer
When counting stopped
When a value is written to timer Ai register, it is written to both reload
register and counter
When counting in progress
When a value is written to timer Ai register, it is written to only reload register
(Transferred to counter at next reload time)
Divide ratio
Count start condition
Count stop condition
Table 1.13.4. Timer specifications in one-shot timer mode
Figure 1.13.10. Timer Ai mode register in one-shot timer mode
(3) One-shot timer mode
In this mode, the timer operates only once. (See Table 1.13.4.) When a trigger occurs, the timer starts up and
continues operating for a given period. Figure 1.13.10 shows the timer Ai mode register in one-shot timer mode.
Bit name
Timer Ai mode register
Function
Bit symbol
TMOD0
b7
b6
b5
0
b4
b3
b2
b1
1 0
b0
Operation mode select bit
1 0 : One-shot timer mode
b1 b0
TMOD1
MR0
MR2
MR1
MR3
0 (Must always be “0” in one-shot timer mode)
0 0 : f
1
0 1 : f
8
1 0 : f
32
1 1 : f
C32
b7 b6
TCK1
TCK0
Count source select bit
0 : One-shot start flag is valid
1 : Selected by event/trigger select
register
Trigger select bit
External trigger select
bit (Note 1)
0 : Falling edge of TAi
IN
pin's input signal (Note 2)
1 : Rising edge of TAi
IN
pin's input signal (Note 2)
Note 1: Valid only when the TA
iIN
pin is selected by the event/trigger select bit
(addresses 0342
16
and 0343
16
). If timer overflow is selected, this bit can be “1” or “0”.
Note 2: Set the corresponding port function select register to I/O port, and port direction
register to “0”.
W
R
AA
AA
AA
AA
AA
AA
AA
AA
Symbol
TAiMR(i=0 to 4)
Address
When reset
0356
16
to 035A
16
00000X00
2
This bit is invalid in M16C/80 series.
Port output control is set by the function select registers A and B.