M16C80 Datasheet, PDF (114/358 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/80 SERIES

M16C/80 Group
13. Timer A
(3) One-shot timer mode
In this mode, the timer operates only once. (See Table 13.4) When a trigger occurs, the timer starts up and
continues operating for a given period. Figure 13.10 shows the timer Ai mode register in one-shot timer mode.
Table 13.4 Timer specifications in one-shot timer mode
Item
Specification
Count source
f1, f8, f32, fC32
Count operation
• The timer counts down
• When the count reaches 000016, the timer stops counting after reloading a
new count
• If a trigger occurs when counting, the timer reloads a new count and restarts counting
Divide ratio
1/n n : Set value
Count start condition
• An external trigger is input
• The timer overflows
• The one-shot start flag is set (= 1)
Count stop condition
• A new count is reloaded after the count has reached 000016
• The count start flag is reset (= 0)
Interrupt request generation timing The count reaches 000016
TAiIN pin function
Programmable I/O port or trigger input
TAiOUT pin function
Programmable I/O port or pulse output (Setting by the corresponding function
select registers A and B)
Read from timer
When timer Ai register is read, it indicates an indeterminate value
Write to timer
• When not counting
Value written to timer Ai register is written to both reload register and counter
• When counting
Value written to timer Ai register is written to only reload register
(Transferred to counter at next reload time)
Timer Ai mode register
b7 b6 b5 b4 b3 b2 b1 b0
0
10
Symbol
Address
When reset
TAiMR(i=0 to 4) 035616 to 035A16 00000X002
Bit symbol
TMOD0
TMOD1
MR0
Bit name
Function
Operation mode select bit ^{b1 b0}
1 0 : One-shot timer mode
This bit is invalid in M16C/80 series.
Port output control is set by the function select registers A and B.
RW
––
MR1
MR2
External trigger select
bit (Note 1)
Trigger select bit
0 : Falling edge of TAiIN pin's input signal (Note 2)
1 : Rising edge of TAiIN pin's input signal (Note 2)
0 : One-shot start flag is valid
1 : Selected by event/trigger select bit
MR3
0 (Set to “0” in one-shot timer mode)
TCK0
TCK1
Count source select bit
b7 b6
0 0 : f1
0 1 : f8
1 0 : f32
1 1 : fC32
Note 1: Valid only when the TAiIN pin is selected by the event/trigger select bit
(addresses 034216 and 034316). 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”.
Figure 13.10 Timer Ai mode register in one-shot timer mode
Rev.1.00 Aug. 02, 2005 ^{Page 103} of 329
REJ09B0187-0100