R8C/13 Group
12.3 Timer (Timer Z)
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 ex
ample in programmable waveform generation mode ).
Table 12.10 Programmable Waveform Generation Mode Specifications
Item
Count source
Count operation
Specification
f1, f2, f8, Timer Y underflow
• 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
and period
Primary period
: (n+1)(m+1)/fi
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
Write “1” (count start) to the TZS bit in the TYZMR register
Write “0” (count stop) to the TZS bit in the TYZMR register
Count start condition
Count stop condition
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].
TZOUT 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(2)
Value written to TZPR register is written to reload register only.
.
Write to timer
Same applies to TZSC register and PREZ register(3)
.
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 enabled 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.
Rev.1.20 Jan 27, 2006 page 93 of 205
REJ09B0111-0120
RENESAS [ RENESAS TECHNOLOGY CORP ]
