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20.2.2
PWM Data Registers U and L (PWDRU, PWDRL)
PWDRU
Bit :
—
Initial value :
R/W :
—
PWDRL
Bit :
PWDRL7
Initial value :
R/W :
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.
7
6
—
PWDRU5
1
1
—
7
6
PWDRL6
PWDRL5
0
0
W
5
4
PWDRU4
PWDRU3
0
0
W
W
5
4
PWDRL4
PWDRL3
0
0
W
W
3
2
PWDRU2
PWDRU1
0
0
W
W
3
2
PWDRL2
PWDRL1
0
0
W
W
Rev. 1.0, 02/00, page 383 of 1141
1
0
PWDRU0
0
0
W
W
1
0
PWDRL0
0
0
W
W
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