Holtek HT66F20 Manual page 171

HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
ADCR0 Register
• HT66F20/HT66F30/HT66F40/HT66F50
Bit 7
Name START
R/W R/W
POR 0
Bit 7 START: Start the A/D conversion
0→1→0: start
0→1: Reset the A/D converter and set EOCB to "1"
This bit is used to initiate an A/D conversion process. The bit is normally low but if set
high and then cleared low again, the A/D converter will initiate a conversion process.
When the bit is set high the A/D converter will be reset.
Bit 6 EOCB: End of A/D conversion flag
0: A/D conversion ended
1: A/D conversion in progress
This read only flag is used to indicate when an A/D conversion process has completed.
When the conversion process is running the bit will be high.
ADOFF: ADC module power on/off control bit
Bit 5
0: ADC module power on
1: ADC module power off
This bit controls the power to the A/D internal function. This bit should be cleared
to zero to enable the A/D converter. If the bit is set high then the A/D converter will
be switched off reducing the device power consumption. As the A/D converter will
consume a limited amount of power, even when not executing a conversion, this may
be an important consideration in power sensitive battery powered applications.
Note: 1. it is recommended to set ADOFF=1 before entering IDLE/SLEEP Mode for
Bit 4 ADRFS: ADC Data Format Control
0: ADC Data MSB is ADRH bit 7, LSB is ADRL bit 4
1: ADC Data MSB is ADRH bit 3, LSB is ADRL bit 0
This bit controls the format of the 12-bit converted A/D value in the two A/D data
registers. Details are provided in the A/D data register section.
Bit 3 Unimplemented, read as "0"
Bit 2~0 ACS2, ACS1, ACS0: Select A/D channel (when ACS4 is "0")
000: AN0
001: AN1
010: AN2
011: AN3
100: AN4
101: AN5
110: AN6
111: AN7
These are the A/D channel select control bits. As there is only one internal hardware
A/D converter each of the eight A/D inputs must be routed to the internal converter
using these bits. If bit ACS4 in the ADCR1 register is set high then the internal 1.25V
will be routed to the A/D Converter.
Rev. 2.50
6 5 4
EOCB ADOFF ADRFS
R R/W R/W
� � 0
saving power.
2. ADOFF=1 will power down the ADC module.
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3 2 1
— ACS2 ACS�
— R/W R/W
— 0 0
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0
ACS0
R/W
0