Rev. 1.0, 02/00, page 383 of 1141
20.2.2
PWM Data Registers U and L (PWDRU, PWDRL)
PWDRU
0
0
1
0
2
0
3
0
4
0
5
0
6
1
7
—
—
—
—
W
PWDRU0
W
PWDRU1
W
PWDRU2
W
PWDRU3
W
PWDRU4
W
PWDRU5
1
Bit :
Initial value :
R/W :
PWDRL
0
0
1
0
2
0
3
0
4
0
5
0
6
7
W
PWDRL0
W
PWDRL1
W
PWDRL2
W
PWDRL3
W
PWDRL4
W
PWDRL5
0
W
PWDRL6
W
PWDRL7
0
Bit :
Initial value :
R/W :
PWM data registers U and L (PWDRU and PWDRL) indicate high level width in one PWN
waveform cycle.
PWDRU and PWDRL form a 14-bit write-only register, with the upper 6 bits assigned to PWDRU
and the lower 8 bits to PWDRL. The value written in PWDRU and PWDRL gives the total high-
level width of one PWM waveform cycle. Both PWDRU and PWDRL are accessible by byte
access only. Word access gives unassured results.
When 14-bit data is written in PWDRU and PWDRL, the contents are latched in the PWM
waveform generator and the PWM waveform generation data is updated. When writing the 14-bit
data, follow these steps:
1. Write the lower 8 bits to PWDRL.
2. Write the upper 6 bits to PWDRU.
Write the data first to PWDRL and then to PWDRU.
PWDRU and PWDRL are write-only registers. When read, all bits always read 1.
PWDRU and PWDRL are initialized to H'C000 by a reset.