
R8C/3GM Group
19. Timer RC
R01UH0284EJ0100 Rev.1.00
Aug 09, 2011
19.5
Timer Mode (Output Compare Function)
This function detects when the contents of the TRC register (counter) and the TRCGRj register (j = A, B, C, or D)
match (compare match). When a match occurs a signal is output from the TRCIOj pin at a given level. The output
compare function, or other mode or function, can be selected for each individual pin.
j = A, B, C, or D
Table 19.9
Specifications of Output Compare Function
Item
Specification
Count source
f1, f2, f4, f8, f32, fOCO40M, fOCO-F
External signal (rising edge) input to TRCCLK pin
Count operation
Increment
Count period
The CCLR bit in the TRCCR1 register is set to 0 (free running operation):
1/fk × 65,536
fk: Count source frequency
The CCLR bit in the TRCCR1 register is set to 1 (TRC register set to 0000h at
TRCGRA compare match):
1/fk × (n + 1)
n: TRCGRA register setting value
Waveform output timing
Compare match
Count start condition
1 (count starts) is written to the TSTART bit in the TRCMR register.
Count stop condition
When the CSEL bit in the TRCCR2 register is set to 0 (count continues after
compare match with TRCGRA).
0 (count stops) is written to the TSTART bit in the TRCMR register.
The output compare output pin retains output level before count stops, the TRC
register retains a value before count stops.
When the CSEL bit in the TRCCR2 register is set to 1 (count stops at compare
match with TRCGRA register).
The count stops at the compare match with the TRCGRA register. The output
compare output pin retains the level after the output is changed by the compare
match.
Interrupt request generation
timing
Compare match (contents of registers TRC and TRCGRj match)
The TRC register overflows.
TRCIOA, TRCIOB, TRCIOC, and
TRCIOD pin functions
Programmable I/O port or output compare output (Selectable individually for
each pin)
INT0 pin function
Programmable I/O port, pulse output forced cutoff signal input, or INT0 interrupt
input
Read from timer
The count value can be read by reading the TRC register.
Write to timer
The TRC register can be written to.
Selectable functions
Output compare output pin selection
One or more of pins TRCIOA, TRCIOB, TRCIOC, and TRCIOD
Compare match output level selection
“L” output, “H” output, or toggle output
Initial output level selection
Sets output level for period from count start to compare match
Timing for setting the TRC register to 0000h
Overflow or compare match with the TRCGRA register
Can be used as an internal timer by disabling timer RC output
Changing output pins for registers TRCGRC and TRCGRD
TRCGRC can be used for output control of the TRCIOA pin and TRCGRD can
be used for output control of the TRCIOB pin.
A/D trigger generation