W921E840A Datasheet, PDF (26/58 Pages) Winbond – 4-BIT MICROCONTROLLER

W921E840A/W921C840
6.9 D/A Converter
The content of 8-bit D/A converter is divided into D/A MSB data register (DAMSB) and D/A LSB data
register (DALSB). The block diagram is shown below.
ANI3
ANI2
ANI1
ANI0
ANIMUX
Register
Vrang = 1.5 V or (2/3)VDD
DACTL.2
8bit D/A Converter
Vani
COMPTR.1
COMPTR.3
Vref
DAMSB 4-bit
Register
DALSB 4-bit
Register
Vpos
Vneg
COMPTR.2
P5.2/Vref
P5.3/DAOUT
• D/A Converter Control Register:
DACTL register: (address = 016H, default data = 0H)
b3
b2
b1
b0
0: D/A converter stop
1: D/A converter start
Reserved
Reserved
0:Vrang = (2/3)VDD
1:Vrang = 1.5V
When the DACTL register bit0 is set by software, the 8-bit D/A converter starts converting. The only
way to disable the D/A converter is to reset the bit0 of the DACTL register using the software control.
The analog signal will be output to the P5.3 pin in this chip if the I/O port works as the D/A output pin.
The power source of the D/A converter can be selected from the (2/3)VDD or 1.5V by programming
the DACTL register bit2.
• D/A Converter LSB Data Register
DALSB register: (address = 017H, default data = 0H)
b3
b2
b1
b0
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