
R8C/14 Group, R8C/15 Group 13. Timers
Rev.2.10 Jan 19, 2006 Page 105 of 253
REJ09B0164-0210
13.2.2 Programmable Waveform Generation Mode
Programmable waveform generation mode is mode to invert the signal output from the TZOUT pin
each time the counter underflows, while the values in the TZPR and TZSC registers are counted
alternately (See Table 13.8 Specification of Programmable Waveform Generation Mode). A
counting starts by counting the value set in the TZPR register. Figure 13.17 shows TZMR and PUM
Registers in Programmable Waveform Generation Mode. Figure 13.18 shows Operating Example of
Timer Z in Programmable Waveform Generation Mode.
NOTES:
1. Even when counting the secondary period, read out the TZPR register.
2. The setting 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 following
primary period after writing to the TZPR register.
3. The TZOCNT bit is enabled by the followings.
• When count starts.
• When the timer Z interrupt request is generated. The contents after the TZOCNT bit is changed
are reflected from the output of the following primary period.
Table 13.8 Specification of Programmable Waveform Generation Mode
Item Specification
Count Source f1, f2, f8, Ti
mer X underflow
Count Operation • Decrement
• When the timer underflows, it reloads the contents of the primary reload and
secondary reload registers alternately before the count continues.
Width and Period of
Output Waveform
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: Setting value in PREZ register, m: setting value in TZPR register, p: setting
value in TZSC register
Count Start Condition Write “1” (count start) to the TZS bit in the TZMR register
Count Stop Condition Write “0” (count stop) to the TZS bit in the TZMR 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]
TZOUT Pin Function Pulse output
(When using this function as a programmable I/O port, set to timer mode.)
INT0
Pin Function Programmable I/O port, or INT0 interrupt input
Read from timer
The count value can be read out by reading the TZPR and PREZ registers
(1)
.
Write to timer The value written to the TZSC, PREZ and TZPR registers is written to the reload
register only
(2)
Select function • Output level latch select function
The TZOPL bit can select the output level during primary and secondary
periods.
• Programmable waveform generation output switch function
When the TZOCNT bit in the TZOC register is set to “0”, the output from the
TZOUT pin is inverted synchronously when Timer Z underflows. And when
setting to “1”, output the value in the P1_3 bit from the TZOUT
pin
(3)
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