TIMER A
7.6 Pulse width modulation (PWM) mode
<When operating as a 16-bit pulse width modulator>
Timer A0 register (Addresses 4716, 4616)
Timer A1 register (Addresses 4916, 4816)
Timer A2 register (Addresses 4B16, 4A16)
Timer A4 register (Addresses 4F16, 4E16)
Timer A9 register (Addresses CF16, CE16)
(b8)
b0 b7
(b15)
b7
b0
Function
Bit
At reset R/W
15 to 0
Undefined WO
Any value in the range from “000016” to “FFFE16” can be set.
Assuming that the set value = n, the “H” level width of the PWM pulse which is output
n
fi
from the TAjOUT pin is expressed as follows :
16
2 –1
(PWM pulse period =
)
fi
fi: Frequency of count source
Note: Use the MOVM or STA(STAD) instruction for writing to this register.
Writing to this register must be performed in a unit of 16 bits.
<When operating as an 8-bit pulse width modulator>
Timer A0 register (Addresses 4716, 4616)
Timer A1 register (Addresses 4916, 4816)
Timer A2 register (Addresses 4B16, 4A16)
(b15)
b7
(b8)
b0 b7
b0
Timer A4 register (Addresses 4F16, 4E16)
Timer A9 register (Addresses CF16, CE16)
Bit
Function
At reset R/W
Undefined WO
7 to 0
Any value in the range from “0016” to “FF16” can be set.
Assuming that the set value = m, the period of the PWM pulse which is output from the
8
TAjOUT pin is expressed as follows:
(m + 1) (2 – 1)
fi
Undefined WO
15 to 8
Any value in the range from “0016” to “FF16” can be set.
Assuming that the set value = n, the “H” level width of the PWM pulse which is output
from the TAjOUT pin is expressed as follows:
n(m + 1)
fi
fi: Frequency of count source
Note: Use the MOVM or STA(STAD) instruction for writing to this register.
Writing to this register must be performed in a unit of 16 bits.
b7 b6 b5 b4 b3 b2 b1 b0
Timer Aj mode register (i = 0 to 2, 4, 9) (Addresses 5616 to 5816, 5A16, DA16)
1 1 1
Bit
0
Bit name
Function
At reset R/W
b1 b0
Operating mode select bits
0
0
0
0
RW
RW
RW
RW
1 1 : PWM mode
1
2
Fix this bit to “1” in PWM mode.
b4 b3
3
Trigger select bits
0 0 :
0 1 :
Writing “1” to count start bit
(TAjIN pin functions as a programmable I/O
port pin.)
4
5
0
0
RW
RW
1 0 : Falling edge of TAjIN pin’s input signal
1 1 : Rising edge of TAjIN pin’s input signal
0 : 16-bit pulse width modulator
1 : 8-bit pulse width modulator
16/8-bit PWM mode select bit
Count source select bits
See Table 7.2.3.
6
7
0
0
RW
RW
Fig. 7.6.1 Structures of timer Aj register and timer Aj mode register in PWM mode
7906 Group User’s Manual Rev.2.0
7-39
RENESAS [ RENESAS TECHNOLOGY CORP ]
