R8C/13 Group
12.3 Timer (Timer Z)
12.3.3 Programmable One-shot Generation Mode
In this mode, upon program command or external trigger input (input to the INT0 pin), the microcom-
puter outputs the one-shot pulse from the TZOUT pin (see “Table 12.11 Programmable One-shot
Generation Mode Specifications”). When a trigger occurs, the timer starts operating from the point
only once for a given period equal to the set value in the TZPR register. The TZSC is unused in this
mode. Figure 12.24 shows the TYZMR register and PUM register in this mode. Figure 12.25 shows
an operation example in this mode.
Table 12.11 Programmable One-shot Generation Mode Specifications
Item
Count source
Count operation
Specification
f1, f2, f8, Timer Y underflow
• Downcounts set value in TZPR register
• When the timer underflows, it reloads the contents of reload register before completing
counting and the TZOS bit is “0”.
• When a count stops, the timer reloads the contents of the reload register before it stops.
(n+1)(m+1)/fi
One-shot pulse output
duration
fi : count source frequency, n: set value in PREZ register, m: set value in TZPR register
• Set TZOS bit in TYZOC register to “1” (start one-shot)(1)
• Input active trigger to INT0 pin(2)
Count start condition
Count stop condition
• When reloading is completed after count value was set to "0016"
• When TZS bit in TYZMR register is set to “0” (stop counting)
• When TZOS bit in TYZOC register is set to “0” (stop one-shot)
Interrupt request generation timing In half cycles of count source, after the timer underflows (at the same time as the TZout
output ends) [Timer Z interrupt].
TZOUT pin function
Pulse output
Use timer mode when using this pin as a programmable I/O port.
_______
_______
INT0 pin function
Programmable I/O port, INT0 interrupt input or external trigger input
_______
• When the INOSTG bit in the PUM register is set to “0” (INT0 one-shot trigger disabled)
_______
Programmable I/O port or INT0 interrupt input
_______
• When the INOSTG bit in the PUM register is set to “1” (INT0 one-shot trigger enabled)
_______
external trigger (INT0 interrupt input)
Read from timer
Write to timer
Count value can be read out by reading TZPR register.
Same applies to PREZ register.
(3)
Value written to TZPR register is written to reload register only
Same applies to PREZ register.
.
Select function
• Output level latch select function
Output level for one-shot pulse waveform is selected by TZOPL bit.
_______
• INT0 pin one-shot trigger control function and polarity select function
_______
Trigger input from INT0 pin can be set to active or inactive by INOSTG bit. Also, an
active trigger's polarity can be selected by INOSEG bit.
NOTES:
1. The TZS bit in the TYZMR register must be set to "1" (start counting).
2. The TZS bit must be set to "1" (start counting), the INT0EN bit in the INTEN register to "1" (enabling_I_N___T__0 input), and
_____
the INOSTG bit in the PUM register to "1" (enabling INT0 one-shot trigger).
Although the trigger input during counting cannot be acknowledged, the I_N__T__0__ interrupt request is generated.
3. The set values are reflected beginning with the next one-shot pulse after writing to the TZPR register.
Rev.1.20 Jan 27, 2006 page 95 of 205
REJ09B0111-0120
RENESAS [ RENESAS TECHNOLOGY CORP ]
