Pulse Output Mode - Renesas M16C Series Hardware Manual

R8C/11 Group

12.1.2 Pulse Output Mode

In this mode, the timer counts an internally generated count source, and outputs from the CNTR0 pin
a pulse whose polarity is inverted each time the timer underflows (See "Table 12.3 Pulse Output mode
Specifications"). Figure 12.5 shows TXMR register in pulse output mode.
Table 12.3 Pulse Output Mode Specifications
Item
Count source
Count operation
Divide ratio
Count start condition
Count stop condition
Interrupt request
generation timing
INT1/CNTR pin function
0
CNTR pin function
0
Read from timer
Write to timer
Select function
NOTES:
1. The level of the output pulse becomes the level when the pulse output starts when the TX register is written to.
Timer X mode register
b 7 b 6 b5 b 4 b 3 b 2 b 1 b 0
0 0 0
N O T E S :
1 . T h e I R b i t i n t h e I N T 1 I C r e g i s t e r m a y b e s e t t o " 1 " ( i n t e r r u p t r e q u e s t e d ) w h e n t h e R 0 E D G b i t i s r e w r i t t e n .
R e f e r t o t h e p a r a g r a p h 1 9 . 2 . 5 " C h a n g i n g I n t e r r u p t F a c t o r " i n t h e U s a g e N o t e s R e f e r e n c e B o o k .
Figure 12.5 TXMR Register in Pulse Output Mode
Rev.1.20 Jan 27, 2006
REJ09B0062-0120
f , f , f , f
1 2 8 32
• Down-count
• When the timer underflows, the contents in the reload register is reloaded and the count
is continued.
1/(n+1)(m+1) n: set value of PREX register, m: set value of TX register
Write "1" (count start) to TXS bit in TXMR register
Write "0" (count stop) to TXS bit in TXMR register
• When Timer X underflows [Timer X interruption]
Pulse output
Programmable I/O port or inverted output of CNTR
Count value can be read by reading TX register.
Same applies to PREX register.
Value written to TX register is written to both reload register and counter.
Same applies to PREX register.
_____
• INT1/CNTR polarity switching function
0
Polarity level at starting of pulse output can be selected with R0EDG bit
• Inverted pulse output function
The inverted pulse of CNTR0 output polarity can be output from the CNTR0 pin
(selected by the TXOCNT bit)
S y m b o l
T X M R
0 1
B i t s y m b o l
Bit name
T X M O D 0
O p e r a t i o n m o d e
s e l e c t b i t 0 , 1
T X M O D 1
INT1/CNTR
R0EDG
switching bit
T i m e r X c o u n t
TXS
s t a r t f l a g
P 3 / C N T R
0
TXOCNT
s e l e c t b i t
T X M O D 2
M u s t s e t t o " 0 " i n p u l s e o u t p u t m o d e
M u s t s e t t o " 0 " i n p u l s e o u t p u t m o d e
TXEDG
TXUND
M u s t s e t t o " 0 " i n p u l s e o u t p u t m o d e
page 74 of 204
Specification
A d d r e s s A f t e r r e s e t
0 0 8 B 0 0
1 6 1 6
Function
b1 b0
0 1 : P u l s e o u t p u t m o d e
polarity 0: CNTR output starts at "H"
0
0
(1) 1: CNTR output starts at "L"
0
0 : Stops counting
1 : Starts counting
0 : Port P3
0
0
1 : CNTR output
0
12.1 Timer (Timer X)
0
(1)
RW
R W
R W
R W
R W
R W
R W
R W
R W