R8C/38T-A Group
17. Timer RC
Under development Preliminary document
Specifications in this document are tentative and subject to change.
R01UH0241EJ0010 Rev.0.10
Page 317 of 730
Aug 05, 2011
17.4.4
Output Waveform Manipulation
By setting the TRCOPR register (timer RC output waveform manipulation register), an output waveform from
the port can be manipulated by INT1 input for timer RC_0.
When the OPE bit in the TRCOPR register is 0, the output waveform manipulation function is disabled. Output
from timer RC ports TRCIOA, TRCIOB, TRCIOC, and TRCIOD is set by registers TRCIOR0, TRCIOR1, and
TRCOER. The output waveform manipulation function is disabled even if a request event for output waveform
manipulation is input.
When the OPE bit is 1, the output waveform manipulation is enabled. If an output waveform manipulation
event (INT1 = low for timer RC_0) is input, bits EA to ED in the TRCOER register are automatically set to 1.
By setting the timer RC port level using bits OPOL0 and OPOL1 in the TRCOPR register, low, high, or high
impedance is forcibly output. After the request event for output waveform manipulation is cancelled, output
waveform manipulation from the timer RC port is stopped and output is restarted by setting the RESTATS bit in
the TRCOPR register. The timing is automatically synchronized so that waveforms less than one cycle are not
output after the output is restarted.
Figures
17.23 to
17.26 show operation examples of output waveform mainpulation.
When the TRCIOB pin is pulled down externally, the OPE bit in the TRCOPR register is 1 (output waveform
manipulation enabled), and bits OPOL1 and OPOL0 are 00b (when pins TRCIOA, TRCIOB, TRCIOC, and
TRCIOD are set to be pulled down externally, timer RC output level is fixed to high impedance during output
waveform manipulation period), and the RESTATS bit is 0 (output waveform manipulation is stopped by
software and output is restarted)
Figure 17.23
Operation Example of Output Waveform Manipulation (1)
Output waveform manipulation
event is cancelled
Output waveform
manipulation event
Output waveform manipulation
event is input
Waveforms less than one
cycle are not output
During output waveform manipulation
period, timer RC output level is fixed to
high impedance, and fixed low when
timer RC pin is pulled down externally
Output waveform manipulation
is stopped by software and
output is restarted
Timer RC output
TRCIOB_XP (internal signal)
EB bit in
TRCOER register
Corresponding output with
output waveform
manipulation disabled
Output control signal
TRCOAE_XN
(internal signal)
TRCIOB output