M306H7MG-XXXFP Datasheet, PDF (78/329 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

M306H7MG-XXXFP/MC-XXXFP/FGFP
9. TIMERS
9.1.2 Event Counter Mode
In event counter mode, the timer counts pulses from an external device or overflows and underflows of other
timers. Timers A2, A3 and A4 can count two-phase external signals. Table 9.2 lists specifications in event
counter mode (when not processing two-phase pulse signal). Table 9.3 lists specifications in event counter
mode (when processing two-phase pulse signal with the timers A2, A3 and A4). Figure 9.8 shows TAiMR
register in event counter mode (when not processing two-phase pulse signal). Figure 9.9 shows TA2MR to
TA4MR registers in event counter mode (when processing two-phase pulse signal with the timers A2, A3 and
A4).
Table 9.2 Specifications in Event Counter Mode (when not processing two-phase pulse signal)
Item
Count source
Count operation
Divided ratio
Count start condition
Specification
• External signals input to TAiIN pin (i=0 to 4) (effective edge can be selected
in program)
• Timer B2 overflows or underflows,
timer Aj (j=i-1, except j=4 if i=0) overflows or underflows,
timer Ak (k=i+1, except k=0 if i=4) overflows or underflows
• Up-count or down-count can be selected by external signal or program
• When the timer overflows or underflows, it reloads the reload register con-
tents and continues counting. When operating in free-running mode, the
timer continues counting without reloading.
1/ (FFFF16 - n + 1) for up-count
1/ (n + 1) for down-count n : set value of TAi register 000016 to FFFF16
Set TAiS bit of TABSR register to “1” (= start counting)
Count stop condition
Set TAiS bit to “0” (= stop counting)
Interrupt request generation timing Timer overflow or underflow
TAiIN pin function
I/O port or count source input
TAiOUT pin function
I/O port, pulse output, or up/down-count select input
Read from timer
Count value can be 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)
Select function
Value written to TAi register is written to only reload register
(Transferred to counter when reloaded next)
• Free-run count function
Even when the timer overflows or underflows, the reload register content is
not reloaded to it
• Pulse output function
Whenever the timer overflows or underflows, the output polarity of TAiOUT
pin is inverted . When not counting, the pin outputs a low.
Rev.2.10 Oct 25, 2006 Page 78 of 326
REJ03B0152-0210