R8C_08 Datasheet, PDF (198/487 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MCU R8C FAMILY / R8C/2x SERIES

R8C/26 Group, R8C/27 Group
14. Timers
• Workaround example (b):
As shown in Figure 14.25 detect the start of the primary period by the TRBO pin output level and write to
registers TRBSC and TRBPR. These write operations must be completed by the beginning of period A.
If the port register’s bit value is read after the port direction register’s bit corresponding to the TRBO pin is
set to 0 (input mode), the read value indicates the TRBO pin output value.
Count source/
prescaler
underflow signal
Period A
TRBO pin output
Primary period
Secondary period
Read value of the port register’s
bit corresponding to the TRBO pin
(when the bit in the port direction
register is set to 0)
(i) (ii) (iii)
Ensure sufficient time
The TRBO output inversion
is detected at the end of the
secondary period.
Upon detecting (i), set the secondary and
then the primary register immediately.
Figure 14.25 Workaround Example (b) When TRBO Pin Output Value is Read
(3) To stop the timer counting in the primary period, use the TSTOP bit in the TRBCR register. In this case,
registers TRBPRE and TRBPR are initialized and their values are set to the values after reset.
14.2.5.3 Programmable one-shot generation mode
The following two workarounds should be performed in programmable one-shot generation mode.
(1) To write to registers TRBPRE and TRBPR during count operation (TCSTF bit is set to 1), note the
following points:
• When the TRBPRE register is written continuously during count operation (TCSTF bit is set to 1), allow
three or more cycles of the count source for each write interval.
• When the TRBPR register is written continuously during count operation (TCSTF bit is set to 1), allow
three or more cycles of the prescaler underflow for each write interval.
(2) Do not set both the TRBPRE and TRBPR registers to 00h.
Rev.2.10 Sep 26, 2008 Page 179 of 453
REJ09B0278-0210