Renesas M16C Series User Manual page 93

M30240 Group
Timer Ai mode register
b7 b6 b5 b4 b3
Figure 1.68: Timer Ai mode register in pulse-width modulation mode
Condition :
Count source (Note1)
TA pin input signal
iIN
Underflow signal of
8-bit prescaler (Note 2)
PWM pulse output
from TA pin
iOUT
Timer Ai interrupt
request bit
f : Frequency of count source
i
(f , f , f )
1 8 32
Note 1: The 8-bit prescaler counts the count source.
Note 2: The 8-bit pulse width modulator counts the 8-bit prescaler's underflow signal.
Note 3: m = 00
16
Figure 1.69: Example of how an 8-bit pulse-width modulator operates
Rev.1.00 Sep 24, 2003 Page 75 of 360
b2 b1 b0
Symbol
1 1 1
TAiMR(i=0 to 4)
Bit symbol Bit name
TMOD0 Operation mode
select bit
TMOD1
Must always be "1" in PWM mode)
MR0
External trigger select bit
MR1
(Note 1)
MR2
Trigger select bit
MR3
16/8 PWM mode select bit
TCK0
Count source select bit
TCK1
Note 1: Valid only when the TAi
(addresses 0382
Note 2: Set the corresponding port direction register to "0".
Reload register high-order 8 bits = 02
Reload register low-order 8 bits = 02
External trigger (falling edge of TAiIN pin input signal) is selected
"H"
"L"
"H"
"L"
"H"
"L"
"1"
"0"
Cleared to "0" when interrupt request is accepted, or cleared by software
to FE ; n = 00 to FE
16 16 16
Address
0396 to 039A
16 16
Function
b1 b0
1 1 : PWM mode
0 : Falling edge of TAi
(Note 2)
1 : Rising edge of TAi
(Note 2)
0 : Count start flag is valid
1 : Selected by event /trigger select register
0 : Functions as a 16-bit pulse width modulator
1 : Functions as an 8-bit pulse width modulator
b7 b6
0 0 : f
1
0 1 : f
8
1 0 : f
32
1 1 : Reserved
pin is selected by the event/trigger select bit.
IN
and 0383 ). If timer overflow is selected, this bit can be "1", or "0".
16 16
16
16
8
X (m + 1) X (2 – 1)
1 / f
i
1 / f X (m + 1)
i
1 / f X (m + 1) X n
i
When reset
00
16
R W
pin's input signal
IN
pin's input signal
IN
Timer A