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Rev. 1.00
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Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
Analog to Digital Converter –
ADC
Analog to Digital Converter –
ADC
ADCR1 Register
SFR Address: F2h
Bit
7
6
5
4
3
2
1
0
Name
ACS4
TSEN
—
VREFAS
VREFIS
ADCK�
ADCK1
ADCK0
R/W
R/W
R/W
—
R/W
R/W
R/W
R/W
R/W
POR
0
0
—
0
0
0
0
0
Bit 7
ACS4:
Internal temperature sensor ADC input control
0: Disable
1: Enable
This bit enables the temperature sensor to the A/D converter. The TSEN bit must first
have been set to enable the temperature sensor circuit. When the ACS4 bit is set high,
the temperature sensor will be routed to the A/D converter and the other A/D input
channels disconnected.
Bit 6
TSEN:
Internal temperature sensor control
0: Disable
1: Enable
This bit controls the internal temperature sensor function to the A/D converter. When
the bit is set high the temperature sensor can be used by the A/D converter.
Bit 5
Unimplemented, read as "0"
Bit 4
VREFAS:
ADC reference voltage select
0: VCCA3 pin
1: Externally supplied on VREF pin or internal voltage reference generator
This bit is used to select the reference voltage for the A/D converter. If the bit is high
then the A/D converter reference voltage is supplied on the external VREF pin or the
internal reference voltage, the choice being made using the VREFIS bit. If the pin is
low then the internal reference is used which is sourced from the power supply pin
VCCA3.
Bit 3
VREFIS:
A/D and DAC reference voltage select
0: Externally supplied on VREF pin
1: Internal Voltage Reference
Bit 2~0
ADCK2~ADCK0:
Select ADC clock source
000: f
SYS
001: f
SYS
/2
010: f
SYS
/4
011: f
SYS
/8
100: f
SYS
/16
101: f
SYS
/32
110: f
SYS
/64
111: f
SYS