C8051F410/1/2/3
78
Rev. 1.1
Important Note About the VREF Pin: Port pin P1.2 is used as the external VREF input and as an output for
the internal VREF. When using either an external voltage reference or the internal reference circuitry, P1.2
should be configured as an analog pin, and skipped by the Digital Crossbar. To configure P1.2 as an ana-
log pin, clear Bit 2 in register P1MDIN to ‘0’ and set Bit 2 in register P1 to '1'. To configure the Crossbar to
skip P1.2, set Bit 2 in register P1SKIP to ‘1’. Refer to
complete Port I/O configuration details. The TEMPE bit in register REF0CN enables/disables the tempera-
ture sensor. While disabled, the temperature sensor defaults to a high impedance state and any ADC0
measurements performed on the sensor result in meaningless data.
SFR Definition 7.1. REF0CN: Reference Control
Bit7:
IDAMRG: IDAC Output Merge Select.
0: IDA1 Output is P0.1.
1: IDA1 Output is P0.0 (Merged with IDA0 Output).
Bit6:
GF. General Purpose Flag.
This bit is a general purpose flag for use under software control.
Bit5:
ZTCEN: Zero-TempCo Bias Enable Bit.
0: ZeroTC Bias Generator automatically enabled when needed.
1: ZeroTC Bias Generator forced on.
Bit4:
REFLV: Voltage Reference Output Level Select.
This bit selects the output voltage level for the internal voltage reference.
0: Internal voltage reference set to 1.5 V.
1: Internal voltage reference set to 2.2 V.
Bit3:
REFSL: Voltage Reference Select.
This bit selects the source for the internal voltage reference.
0: VREF pin used as voltage reference.
1: VDD used as voltage reference.
Bit2:
TEMPE: Temperature Sensor Enable Bit.
0: Internal Temperature Sensor off.
1: Internal Temperature Sensor on.
Bit1:
BIASE: Internal Analog Bias Generator Enable Bit.
0: Internal Analog Bias Generator automatically enabled when needed.
1: Internal Analog Bias Generator on.
Bit0:
REFBE: Internal Reference Buffer Enable Bit.
0: Internal Reference Buffer disabled.
1: Internal Reference Buffer enabled. Internal voltage reference driven on the VREF pin.
R/W
Reset Value
IDAMRG
GF
ZTCEN
REFLV
REFSL
TEMPE
BIASE
REFBE
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
0xD1