R8C/10 Group
Rev.1.20 Jan 27, 2006 page 78 of 180
REJ09B0019-0120
12.3.2 Programmable Waveform Generation Mode
In this mode, an signal output from the TZOUT pin is inverted each time the counter underflows, while
the values in the TZPR register and TZSC register are counted alternately (see “Table 12.10 Program-
mable Waveform Generation Mode Specifications”). A counting starts by counting the value set in the
TZPR register. Figure 12.23 shows TYZMR and PUM registers in this mode. The Timer Z operates in
the same way as the Timer Y in this mode. See Figure 12.17 (Timer Y operation example in program-
mable waveform generation mode ).
Item Specification
Count source f1, f2, f8, Timer Y underflow
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
fi : Count source frequency
n: Set value in PREZ register, m: Set value in TZPR register, p: Set value in TZSC register
Count start condition Write “1” (count start) to the TZS bit in the TYZMR register
Count stop condition Write “0” (count stop) to the TZS bit in the TYZMR register
Interrupt request generation timing
In half of count source, after timer Z underflows during secondary period (at the same
time as the TZout output change) [Timer Z interrupt]
TZ
OUT pin function Pulse output
Use timer mode when using this pin as a programmable I/O port.
_____
INT0 pin functions Programmable I/O port, or INT0 interrupt input
Read from timer Count value can be read out by reading TZPR register.
Same applies to PREZ register
(1)
.
Write to timer
Value written to TZPR register is written to reload register only.
Same applies to TZSC register and PREZ register
(2)
.
Select function • Output level latch select function
The output level during primary and secondary periods is selected by the TZOPL bit.
• Programmable waveform generation output switching function
The output from TZOUT is inverted synchronously when Timer Z underflows by setting
the TZOCNT bit in the TYZOC register to “0”. A value in the P3_1 bit is output from the
TZOUT by setting to “1”
(3)
.
NOTES:
1. Even when counting the secondary period, read out the TZPR register.
2. The set value in the TZPR register and TZSC register are made effective by writing a value to the TZPR register. The
set values are reflected to the waveform output beginning with the next primary period after writing to the Timer Z
primary register.
3. The TZOCNTbit is enabled in the following timings
• When count starts
• When Timer Z interrupt request is generated
Therefore, pulse is output from the next primary period depending on the setting value of the TZOCNT bit.
Table 12.10 Programmable Waveform Generation Mode Specifications
12.3 Timer (Timer Z)
(11 pages)
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