R5F21133DFP RENESAS [Renesas Technology Corp], R5F21133DFP Datasheet - Page 87

• Manufacturer Part Number: R5F21133DFP
• Description: 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY/R8C/Tiny SERIES
• Manufacturer: RENESAS [Renesas Technology Corp]

R8C/13 Group
Rev.1.20
REJ09B0111-0120
Table 12.5 Pulse Width Measurement Mode Specifications
Figure 12.7 TXMR Register in Pulse Width Measurement Mode
Count source
Count operation
Count start condition
Count stop condition
Interrupt request
generation timing
INT1/CNTR
CNTR
Read from timer
Write to timer
Select function
T i m e r X m o d e r e g i s t e r
b 7 b 6 b 5 b4 b 3 b 2 b 1 b 0
12.1.4 Pulse Width Measurement Mode
0 0
N O T E S :
In this mode, the timer measures the pulse width of an external signal fed to INT1/CNTR0 pin (See
“Table 12.5 Pulse Width Measurement Mode Specifications”). Figure 12.7 shows the TXMR register
in pulse width measurement mode. Figure 12.8 shows an operation example in pulse width measure-
ment mode.
1 . I 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 .
Jan 27, 2006
0
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 .
pin function
Item
0
0
0
pin function
1
page 76 of 205
1
B i t s y m b o l
T X O C N T
T X M O D 2
f
• Down-count
• Continuously counts the selected signal only when the measurement pulse is "H" level,
• When the timer underflows, the contents in the reload register is reloaded and the count
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]
• Rising or falling of CNTR0 input (end of measurement period) [INT1 interrupt]
Measurement pulse input
Programmable I/O port
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
“H” or “L” level duration can be selected with R0EDG bit as the input pulse measurement
T X M O D 0
T X M O D 1
R0EDG
T X S
T X U N D
T X E D G
1
or conversely only "L" level.
is contiuned.
, f
_____
Symbol
TXMR
2
, f
8
, f
32
I N T 1 / C N T R
s w i t c h i n g b i t
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 i m e r X c o u n t
s t a r t f l a g
S e t t o " 0 " i n p u l s e w i d t h m e a s u r e m e n t m o d e
S e t t o " 0 " i n p u l s e w i d t h m e a s u r e m e n t m o d e
S e t t o " 0 " i n p u l s e w i d t h m e a s u r e m e n t m o d e
S e t t o " 0 " i n p u l s e w i d t h m e a s u r e m e n t m o d e
0
polarity switching function
B i t n a m e
0
(1 )
Address
p o l a r i t y
008B
16
b 1 b 0
0 : S t o p s c o u n t i n g
1 : S t a r t s c o u n t i n g
[CNTR0]
0 : Measures “H” level width
1 : Measures “L” level width
[INT1]
0 : Rising edge
1 : Falling edge
1 1 : Pulse width measurement mode
Specification
After reset
00
16
F u n c t i o n
12.1 Timer (Timer X)
R W
R W
R W
R W
R W
R W
R W
R W
R W