Holtek HT45F23A Manual page 81

HT45F23A/HT45F24A
TinyPower Flash MCU with OPA & Comparators
TM
ACS3 ~ ACS0: Select A/D channel
Bit 3~0
0000: AN0
0001: AN1
0010: AN2
0011: AN3
0100: AN4
0101: AN5
0110: AN8, connect Op Amp 1 output (A1E)
0111: AN9, connect Op Amp 2 output (A2E)
1000: AN6
1001: AN7
These are the A/D channel select control bits. As there is only one internal hardware A/D
converter each of the ten A/D inputs must be routed to the internal converter using these
bits.
ACSR Register
Bit 7
Name —
R/W —
POR 1
Bit 7 unimplemented, read as "1"
Bit 6 ADONB: ADC module power on/off control bit
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 devices 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 ADONB=1 before entering IDLE/SLEEP Mode for
VRSEL: Selecte ADC reference voltage
Bit 5
0: Internal ADC power
1: VREF pin or LDO output (2.4V/3.3V)
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 LDO
output (2.4V/3.3V). If the pin is low, then the internal reference is used which is taken
from the power supply pin VDD.
Bit 4~3 unimplemented, read as "0"
ADCS2, ADCS1, ADCS0: Select ADC clock source
Bit 2~0
000: f
001: f
010: f
011: Undefined
100: f
101: f
110: f
111: Undefined
These three bits are used to select the clock source for the A/D converter.
Rev. 1.40
6 5 4
ADONB VRSEL —
R/W R/W —
0 0 —
saving power.
2. ADONB=1 will power down the ADC module.
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81
3 2 1
— ADCS2 ADCS1
— R/W R/W
— 0 0
March 29, 2019
0
ADCS0
R/W
0