M16C30P_07 Datasheet, PDF (121/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
14. Timers
14.1.3 One-shot Timer Mode
In one-shot timer mode, the timer is activated only once by one trigger (see Table 14.4). When the trigger
occurs, the timer starts up and continues operating for a given period. Figure 14.11 shows the TAiMR Register
in One-Shot Timer Mode.
Table 14.4 Specifications in One-shot Timer Mode
Item
Specification
Count Source
f1, f2, f8, f32, fC32
Count Operation
• Down-count
• When the counter reaches 0000h, it stops counting after reloading a new
value
• If a trigger occurs when counting, the timer reloads a new count and restarts
counting
Divide Ratio
1/n n : set value of TAi register (i=0 to 2) 0000h to FFFFh
However, the counter does not work if the divide-by-n value is set to 0000h.
Count start Condition
TAiS bit in the TABSR register = 1 (start counting) and one of the following
triggers occurs.
• External trigger input from the TAiIN pin
• Timer B2 overflow or underflow,
Timer Aj (j=i-1, however, do not set when i=0) overflow or underflow,
Timer Ak (k=i+1, however, do not set when i=2) overflow or underflow
• The TAiOS bit in the ONSF register is set to “1”(= timer starts)
Count Stop Condition • When the counter is reloaded after reaching “0000h”
• TAiS bit is set to “0” (= stop counting)
Interrupt Request
Generation Timing
When the counter reaches “0000h”
TAiIN Pin Function
I/O port or trigger input
TAiOUT Pin Function I/O port or pulse output
Read from Timer
An indeterminate value is read by reading TAi register
Write to Timer
• When not counting and until the 1st count source is input after counting start
Value written to TAi register is written to both reload register and counter
• When counting (after 1st count source input)
Value written to TAi register is written to only reload register
(Transferred to counter when reloaded next)
Select Function
• Pulse output function
The timer outputs a low when not counting and a high when counting.
Rev.1.22 Mar 29, 2007 Page 105 of 291
REJ09B0179-0122