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Under
development
Preliminary Specifications REV.D
Specifications in this manual are tentative and subject to change.
Mitsubishi Microcomputers
M16C/80 group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Timer A
96
Item
Specification
Count source
f1, f8, f32, fc32
Count operation
Down count
When the timer underflows, it reloads the reload register contents before
continuing counting
Divide ratio
1/(n+1)
n : Set value
Count start condition
Count start flag is set (= 1)
Count stop condition
Count start flag is reset (= 0)
Interrupt request generation timing
When the timer underflows
TAiIN pin function
Programmable I/O port or gate input
TAiOUT pin function
Programmable I/O port or pulse output (Setting by corresponding port function
select register and peripheral function select register)
Read from timer
Count value can be read out by reading timer Ai register
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)
Select function
Gate function
Counting can be started and stopped by the TAiIN pin’s input signal
Pulse output function
Each time the timer underflows, the TAiOUT pin’s polarity is reversed
(1) Timer mode
In this mode, the timer counts an internally generated count source. (See Table 1.13.1.) Figure 1.13.5
shows the timer Ai mode register in timer mode.
Table 1.13.1. Specifications of timer mode
Note 1: The bit can be “0” or “1”.
Note 2: Set the corresponding port function select register to I/O port, and port
direction register to “0”.
Timer Ai mode register
Symbol
Address
When reset
TAiMR(i=0 to 4)
035616 to 035A16 00000X002
Bit name
Function
Bit symbol
W
R
b7
b6
b5
b4
b3
b2
b1
b0
Operation mode
select bit
0 0 : Timer mode
b1 b0
TMOD1
TMOD0
MR0
Gate function select bit
0 X (Note 1): Gate function not available
(TAiIN pin is a normal port pin)
1 0 : Timer counts only when TAiIN pin is
held “L” (Note 2)
1 1 : Timer counts only when TAiIN pin is
held “H” (Note 2)
b4 b3
MR2
MR1
MR3
0 (Set to “0” in timer mode)
0 0 : f1
0 1 : f8
1 0 : f32
1 1 : fC32
b7 b6
TCK1
TCK0
Count source select bit
00
0
This bit is invalid in M16C/80 series.
Port output control is set by the function select registers A and B.
– –
Figure 1.13.5. Timer Ai mode register in timer mode