Renesas R8C/20 User Manual

R8C/20 Group, R8C/21 Group 14. Timers
Rev.2.00 Aug 27, 2008 Page 126 of 458
REJ09B0250-0200
14.1.2 Pulse Output Mode
Pulse output mode is mode to count the count source internally generated and outputs the pulse which inverts
the polarity from the TRAIO pin each time the timer underflows (see Table 14.3 Pulse Output Mode
Specifications).
Figure 14.7 shows the TRAIOC Register in Pulse Output Mode.
NOTE:
1. The level of output pulse turn into the level when the pulse output starts by writing the TRAMR
register.
Table 14.3 Pulse Output Mode Specifications
Item Specification
Count Sources f1, f2, f8, fOCO
Count Operations • Decrement
• When the timer underflows, the contents in the reload register is reloaded and
the count is inherited
Divide Ratio 1/(n+1)(m+1)
n: setting value of TRAPRE register, m: setting value of TRA register
Count Start Condition Write 1 (count starts) to the TSTART bit in the TRACR register
Count Stop Conditions • Write 0 (count stops) to the TSTART bit in the TRACR register
• Write 1 (count forcibly stops) to the TSTOP bit in the TRACR register
Interrupt Request
Generation Timing
When timer RA underflows [timer RA interrupt]
INT1
/TRAIO Pin
Function
Pulse output, programmable output port, or INT1
interrupt
(1)
TRAO Pin Function
Programmable I/O port or inverted output of TRAIO
(1)
Read from Timer
The count value can be read by reading the TRA and TRAPRE registers
Write to Timer • When registers TRAPRE and TRA are written while the count is stopped,
values are written to both the reload register and counter.
• When registers TRAPRE and TRA are written during the count, values are
written to the reload register and counter (refer to 14.1.1.1 Timer Write
Control during Count Operation).
Select Functions
• TRAIO output polarity switch function
The TEDGSEL bit in the TRAIOC register can select the polarity level when
the pulse output starts
(1)
• Inverted pulse output function
The pulse which inverts the polarity of the TRAIO output can be output from
the TRAO pin (selected by the TOENA bit in the TRAIOC register)
• Pulse output stop function
The pulse output from the TRAIO pin can be stopped by the TOPCR bit.
•INT1
/TRAIO pin select function
P1_7 or P1_5 is selected by the TIOSEL bit in the TRAIOC register.

Renesas R8C/20 Specifications

General

Brand	Renesas
Model	R8C/20
Category	Control Unit
Language	English