7220 Datasheet, PDF (96/303 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER

FUNCTIONAL DESCRIPTION
2.10 PWM
2.10.4 14-bit PWM output control
How to control the 14-bit PWM output is described below.
Œ Set “0” to bit 0 of PWM output control register 1 (address 00D516) to supply the PWM count source (this
bit is cleared to “0” when reset).
 Set the high-order 8 bits of the output data to the DA-H register.
Ž Set the low-order 6 bits of the output data to the DA-L register.
 Data is written to the 14-bit PWM circuit by writing data to the DA-L register.
For this reason, even when changing only the high-order 8 bits of the output data, be sure to write the
low-order 6 bits data to the DA-L register again.
Conversely, when changing low-order 6 bits only, it needs to only write data to the DA-L register, and
needs not write the high-order 8-bit data again.
 Select the output polarity by bit 2 of PWM output control register 2 (address 00D616). When setting to
“0,” a positive polarity is selected; when “1,” a negative polarity is selected.
‘ 14-bit PWM is output from the D-A pin by clearing bit 1 of PWM output control register 1 to “0.” When
setting to “1,” pin D-A functions as a 1-bit general-purpose output port. In this case, it is possible to
specify either HIGH output (= “1”) or LOW output(= “0”) output by bit 4 of PWM output control register
2.
PWM Output Control Register 1
b7 b6 b5 b4 b3 b2 b1 b0
PWM output control register 1 (PW) [Address 00D516]
B
Name
Functions
0 DA, PWM count source 0 : Count source supply
selection bit (PW0) 1 : Count source stop
1 DA/PN4 output
selection bit (PW1)
0 : DA output
1 : PN4 output
2 P00/PWM0 output
selection bit (PW2)
0: P00 output
1: PWM0 output
3 ^{P01/PWM1 output}
selection bit (PW3)
0: P01 output
1: PWM1 output
4 P02/PWM2 output
selection bit (PW4)
0: P02 output
1: PWM2 output
5 P03/PWM3 output
selection bit (PW5)
6 P04/PWM4 output
selection bit (PW6)
7 P05/PWM5 output
selection bit (PW7)
0: P03 output
1: PWM3 output
0: P04 output
1: PWM4 output
0: P05 output
1: PWM5 output
After reset R W
0 RW
0 RW
0 RW
0 RW
0 RW
0 RW
0 RW
0 RW
Fig. 2.10.6 PWM output control register 1 (address 00D516)
7220 Group User’s Manual
2-69