C8051F120/1/2/3/4/5/6/7 C8051F130/1/2/3
Rev. 1.4
117
9.3.
Reference Configuration on the C8051F130/1/2/3
On the C8051F130/1/2/3 devices, the VREF0 pin provides a voltage reference input for ADC0, which can
be connected to an external precision reference or the internal voltage reference, as shown in Figure 9.3.
The REF0CN register for the C8051F130/1/2/3 is described in SFR Definition 9.3.
Figure 9.3. Voltage Reference Functional Block Diagram (C8051F130/1/2/3)
SFR Definition 9.3. REF0CN: Reference Control (C8051F130/1/2/3)
Recommended Bypass
Capacitors
x2
VREF
ADC0
Ref
VREF0
4.7
μ
F
0.1
μ
F
External
Voltage
Reference
Circuit
R1
VDD
DGND
Bias to ADC
1.2V
Band-Gap
EN
+
REF0CN
REF
B
E
BIAS
E
TEMPE
Bits7–5: UNUSED. Read = 000b; Write = don’t care.
Bits4–3: Reserved: Must be written to 0.
Bit2:
TEMPE: Temperature Sensor Enable Bit.
0: Internal Temperature Sensor Off.
1: Internal Temperature Sensor On.
Bit1:
BIASE: ADC/DAC Bias Generator Enable Bit. (Must be ‘1’ if using ADC or VREF).
0: Internal Bias Generator Off.
1: Internal Bias Generator On.
Bit0:
REFBE: Internal Reference Buffer Enable Bit.
0: Internal Reference Buffer Off.
1: Internal Reference Buffer On. Internal voltage reference is driven on the VREF pin.
SFR Page:
SFR Address:
0
0xD1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
-
-
-
Reserved Reserved
TEMPE
BIASE
REFBE
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Summary of Contents for C8051F12 Series
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