ADUC7023 Analog Devices, ADUC7023 Datasheet - Page 35

• Manufacturer Part Number: ADUC7023
• Description: Precision Analog Microcontroller, 12-Bit Analog I/O, ARM7TDMI MCU
• Manufacturer: Analog Devices

Specifications of ADUC7023

• Mcu Core: ARM7 TDMI
• Mcu Speed (mips): 40
• Sram (bytes): 8192Bytes
• Gpio Pins: 20
• Adc # Channels: 12
• Other: PWM

Table 29. TEMPREF MMR Bit Designations
Bit
15 to 9
8
7 to 0
BAND GAP REFERENCE
The ADuC7023 provides an on-chip band gap reference of
2.5 V, which can be used for the ADC and DAC. This internal
reference also appears on the V
reference, a 0.47 μF capacitor must be connected from the external
V
ADC conversions. This reference can also be connected to an
external pin (V
the system.
REF
pin to AGND to ensure stability and fast response during
where TEMREF[8] = 1.
Note that ADC code value 2292 is a default value
Description
Reserved.
Temperature reference voltage sign.
Temperature sensor offset calibration voltage.
To calculate the V
perform the following calculation:
If TEMPREF sign negative, subtract TEMPREF from 2292
or
If TEMREF sign positive, add TEMPREF to 2292
where:
TEMPREF[8] = 0.
Then,
where:
Insert V
where:
when using the TEMREF register. It is not an exact
value and must only be used with the TEMPREF
register.
C
C
V
C
V
T
V
consecutive conversions.
V
T – T
REF
REF
TREF
TREF
TREF
TREF
REF
ADC
TREF
TREF
) and used as a reference for other circuits in
is 27°C, when using TEMREF register.
is 2.5 V, internal reference voltage.
is the average ADC result from two
is calculated as above.
= 2292 − TEMPREF[7:0]
= TEMPREF[7:0] + 2292
= (C
is calculated as above.
REF
into
TREF
= (V
× V
TREF
ADC
REF
REF
from the TEMPREF register,
– V
)/4096 × 1000
pin. When using the internal
TREF
) × K
Rev. B | Page 35 of 96
An external buffer is required because of the low drive capability
of the V
external reference input on the V
REFCON Register
Name:
Address:
Default value:
Access:
Function:
Table 22. REFCON MMR Bit Designations
Bit
7 to 2
1
0
To connect an external reference source to the ADuC7023,
configure REFCON = 0x00. ADC and the DACs can be
configured to use the same or different reference resource. See
Table 41.
REF
Description
Reserved.
Internal reference power-down bit.
This bit is set to 1 to power down the internal
reference source. This bit should be set when
connecting an external reference source.
This bit is cleared to enable the internal reference.
This bit is cleared by default.
Internal reference output enable.
This bit is set by the user to connect the internal 2.5 V
reference to the V
for an external component but needs to be buffered.
This bit is cleared by the user to disconnect the
reference from the V
output. A programmable option also allows an
REFCON
0xFFFF048C
0x00
Read/write
The band gap reference interface consists
of an 8-bit MMR REFCON described in
Table 22.
REF
pin. The reference can be used
REF
pin.
REF
pin.
ADuC7023