Timer A
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Preliminary Specifications REV.E
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M30220 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
74
Item
Specification
Count source
Count operation
Two-phase pulse signals input to TAi
IN
or TAi
OUT
pin
Up count or down count can be selected by two-phase pulse signal
When the timer overflows or underflows, the reload register content is
reloaded and the timer starts over again (Note)
1/ (FFFF
16
-
n + 1) for up count
1/ (n + 1) for down count
Count start flag is set (= 1)
Count start flag is reset (= 0)
Interrupt request generation timing
Timer overflows or underflows
TAi
IN
pin function
Two-phase pulse input
TAi
OUT
pin function
Two-phase pulse input
Read from timer
Count value can be read out by reading timer A2, A3, A4 or A7 register
Write to timer
When counting stopped
When a value is written to timer A2, A3, A4 or A7 register, it is written to both
reload register and counter
When counting in progress
When a value is written to timer A2, A3, A4 or A7 register, it is written to only
reload register. (Transferred to counter at next reload time.)
Select function
Normal processing operation
The timer counts up rising edges or counts down falling edges on the TAi
IN
pin when input signal on the TAi
OUT
pin is “H”
Divide ratio
n : Set value
Count start condition
Count stop condition
Multiply-by-4 processing operation
If the phase relationship is such that the TAi
IN
pin goes “H” when the input
signal on the TAi
OUT
pin is “H”, the timer counts up rising and falling edges
on the TAi
OUT
and TAi
IN
pins. If the phase relationship is such that the
TAi
IN
pin goes “L” when the input signal on the TAi
OUT
pin is “H”, the timer
counts down rising and falling edges on the TAi
OUT
and TAi
IN
pins.
Note: This does not apply when the free-run function is selected.
Table 1.13.3. Timer specifications in event counter mode (when processing two-phase pulse signal with timers A2, A3, A4 and A7)
TAi
OUT
Up
count
Up
count
Up
count
Down
count
Down
count
Down
count
TAi
IN
(i=2, 3, 7)
TAi
OUT
TAi
IN
(i=3, 4)
Count up all edges
Count up all edges
Count down all edges
Count down all edges