R8C/20 Group, R8C/21 Group 14. Timers
Rev.2.00 Aug 27, 2008 Page 201 of 458
REJ09B0250-0200
i = 0 or 1, j = either B, C or D,
h = either A, B, C or D
Table 14.27 PWM Mode Specifications
Item Specification
Count Sources f1, f2, f4, f8, f32, fOCO40M
External signal input to the TRDCLK pin (valid edge selected by a
program)
Count Operations Increment
PWM Waveform PWM period: 1/fk x (m+1)
Active level width: 1/fk x (m-n)
Inactive level width: 1/fk x (n+1)
fk: Frequency of count source
m: Setting value in the TRDGRAi register
n: Setting value in the TRDGRji register
Count Start Condition Write 1 (count starts) to the TSTARTi bit in the TRDSTR register.
Count Stop Conditions • Write 0 (count stops) to the TSTARTi bit in the TRDSTR register
when the CSELi bit in the TRDSTR register is set to 1.
• The PWM output pin holds output level before the count stops.
• When the CSELi bit in the TRDSTR register is set to 0, the count
stops at the compare match in the TRDGRAi register.
• The PWM output pin holds level after output change by the compare
match.
Interrupt Request Generation
Timing
• Compare match (the content in the TRDi register matches with the
content in the TRDGRhi register.)
• TRDi register overflows
TRDIOA0 Pin Function Programmable I/O port or TRDCLK (external clock) input
TRDIOA1 Pin Function Programmable I/O port
TRDIOB0, TRDIOC0, TRDIOD0,
TRDIOB1, TRDIOC1, TRDIOD1
Pin Functions
Programmable I/O port or pulse output (select every 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 TRDi register.
Write to Timer The value can be written to the TRDi register.
Selection Functions • 1 to 3 PWM output pins selected per 1 channel
• Either 1 pin or multiple pins of the TRDIOBi, TRDIOCi or TRDIODi
pin.
• The active level selected every pin.
• Initial output level selected every pin.
• Synchronous operation (refer to 14.3.3 Synchronous Operation.)
• Buffer operation (refer to 14.3.2 Buffer Operation.)
• Pulse output forced cutoff signal input (refer to 14.3.4 Pulse Output
Forced Cutoff.)
m + 1
n + 1 m - n
(When “L” is selected for the active level)
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