R5F21133DFP RENESAS [Renesas Technology Corp], R5F21133DFP Datasheet - Page 90

• 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
Figure 12.10 Operation Example in Pulse Period Measurement Mode
U n d e r f l o w s i g n a l
o f p r e s c a l e r X
T X S b i t i n
T X M R r e g i s t e r
C N T R 0 p i n
i n p u t
T i m e r X
r e a d - o u t b u f f e r
T X E D G b i t i n
T X M R r e g i s t e r
TXUND bit in
TXMR register
IR bit in TXIC
register
I R b i t i n I N T 1 I C
r e g i s t e r
c o n t e n t s
C o n t e n t s o f
C o n d i t i o n s : A p e r i o d f r o m o n e r i s i n g e d g e t o t h e n e x t r i s i n g e d g e o f m e a s u r e m e n t p u l s e i s m e a s u r e d ( R 0 E D G = 0 )
NOTES:
1. The contents of the read-out buffer can be read when the TX register is read in pulse period measurement mode.
2. After an active edge of measurement pulse is input, the TXEDG bit in the TXMR register is set to "1" (active edge found)
3. The TX register should be read before the next active edge is input after the TXEDG bit is set to "1" (active edge found).
4. When set to "0" by program, use a MOV instruction to write "0" to the TXEDG in the TXMR register. At the same time,
5. When set to "0" by program, use a MOV instruction to write "0" to the TXUND in the TXMR register. At the same time,
6. The TXUND and TXEDG bits are both set to "1" if the timer underflows and reloads on an active edge simultaneously. In
7. If the CNTR
Jan 27, 2006
when the prescaler X underflows for the second time.
The contents in the read-out buffer is retained until the TX register is read. If the TX register is not read before the next
active edge is input, the measured result of the previous period is retained.
write "1" to the TXUND bit.
write "1" to the TXEDG bit.
this case, the validity of the TXUND bit should be determined by the contents of the read-out buffer.
read buffer. If "L" level, the following count value is the one of the read buffer.
w i t h T X r e g i s t e r i n i t i a l v a l u e = 0 F
1
0
active edge is input, when the prescaler X underflow signal is "H" level, its count value is the one of the
“ 1 ”
“ 0 ”
“1”
“ 0 ”
“1”
“0”
“1”
“0”
“ 1 ”
“ 0 ”
“ 1 ”
“ 0 ”
page 79 of 205
S t a r t s c o u n t i n g
0 F
S e t t o " 1 " b y p r o g r a m
0 F
1 6
1 6
0 E
( 7 )
1 6
0F
R e t a i n e d
16
Cleared to “0” when interrupt request is accepted, or cleared by program
T i m e r X
r e l o a d s
(2)
0E
1 6
16
0 E
.
0D
1 6
Cleared to “0” when interrupt request is accepted, or cleared by program
16
0 C
1 6
Cleared to "0" by program
0 B
1 6
0 A
0 A
1 6
T i m e r X r e a d
1 6
0 9
09
1 6
16
(3)
0 8
Retained
1 6
(2)
0F
08
(4)
16
Timer X
reloads
16
(7)
0E
16
0D
0 D
Timer X read
16
1 6
C l e a r e d t o " 0 " b y p r o g r a m
(3)
01
0 1
12.1 Timer (Timer X)
16
1 6
0 0
0 0
1 6
1 6
(6)
0 F
0 F
1 6
T i m e r X
r e l o a d s
1 6
(5)
0 E
0 E
1 6
1 6