R8C/10 Group
Rev.1.20 Jan 27, 2006 page 70 of 180
REJ09B0019-0120
12.2.2 Programmable Waveform Generation Mode
In this mode, an signal output from the TYOUT pin is inverted each time the counter underflows, while
the values in the TYPR register and TYSC register are counted alternately (see “Table 12.8 Program-
mable Waveform Generation Mode Specifications”). A counting starts by counting the set value in the
TYPR register. Figure 12.16 shows the TYZMR register in programmable waveform generation mode.
Figure 12.17 shows the operation example.
Item Specification
Count source f1, f8, fRING
Count operation • Down count
• When the timer underflows, it reloads the contents of primary reload register and sec-
ondary reload register alternately before continuing counting.
Output waveform width Primary period : (n+1)(m+1)/f
i
and period Secondary period : (n+1)(p+1)/fi
Period : (n+1){(m+1)+(p+1)}/fi
n: set value in PREY register, m: set value in TYPR register, p: set value in TYSC register
f
i
: Count source frequency
Count start condition Write “1” (count start) to TYS bit in TYZMR register
Count stop condition Write “0” (count stop) to TYS bit in TYZMR register
Interrupt request generation timing
In half of count source, after timer Y underflows during secondary period (at the same
time as the CNTR, output change) [Timer Y interrupt]
_____
INT2/CNTR1 pin functions Pulse output
Use timer mode when using this pin as a programmable I/O port.
Read from timer Count value can be read out by reading TYPR register.
Same applies to PREY register
(1)
.
Write to timer
Value written to TYPR register is written to only reload register.
Same applies to TYSC register and PREY register
(2)
.
Select function • Output level latch select function
The output level during primary and secondary periods is selected by the TYOPL bit.
• Programmable waveform generation output switching function
When the TYOCNT bit in the TYZOC register is set to “0”, the output from TYOUT is
inverted synchronously when Timer Y underflows during the secondary period. And
when set to “1”, a value in the P3_2 bit is output from TYOUT synchronously when Timer
Y underflows during the secondary period
(3)
.
NOTES:
1. Even when counting the secondary period, read out the TYPR register.
2. The set value in the TYPR register and TYSC register are made effective by writing a value to the TYPR register. The
written values are reflected to the waveform output from the next primary period after writing to the TYPR register.
3. The TYOCNTbit is enabled in the following timings
• When count starts
• When Timer Y interrupt request is generated
Therefore, pulse is output from the next primary period depending on the setting value of the TYOCNT bit.
Table 12.8 Programmable Waveform Generation Mode Specifications
12.2 Timer (Timer Y)
(8 strony)
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