ADUC7039BCP6Z-RL Analog Devices Inc, ADUC7039BCP6Z-RL Datasheet - Page 45

• Manufacturer Part Number: ADUC7039BCP6Z-RL
• Description: Flash 64k ARM7 Dual 16-Bit ADC LIN I.C.
• Manufacturer: Analog Devices Inc
• Series: MicroConverter® ADuC7xxxr

Specifications of ADUC7039BCP6Z-RL

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 20.48MHz
• Connectivity: LIN, SPI
• Peripherals: POR, Temp Sensor, WDT
• Number Of I /o: 6
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 3.5 V ~ 18 V
• Data Converters: A/D 2x16b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 115°C
• Package / Case: 32-LFCSP
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Eeprom Size: -
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption

Understanding the Offset and Gain Calibration Registers
The output of the average block in the ADC signal flow can
be considered a fractional number with a span for a ±full-scale
input of approximately ±0.75. The span is less than ±1.0 because
there is attenuation in the modulator to accommodate some
overrange capacity on the input signal. The exact value of the
attenuation varies slightly from part-to-part because of
manufacturing tolerances.
The offset coefficient is read from the ADC0OF calibration
register. This value is a 16-bit, twos complement number. The
range of this number, in terms of the signal chain, is effectively
±1.0. Therefore, 1 LSB of the ADC0OF register is not the same
as 1 LSB of ADC0DAT.
A positive value of ADC0OF indicates that when offset is
subtracted from the output of the filter, a negative value is
added. The nominal value of this register is 0x0000, indicating
zero offset is to be removed. The actual offset of the ADC can
vary slightly from part-to-part and at different PGA gains. The
offset within the ADC is minimized if the chopping mode is
active (ADCFLT[15] = 1).
The gain coefficient is a unitless scaling factor. The 16-bit value
in this register is divided by 16,384 and then multiplied by the
offset corrected value. The nominal value of this register equals
0x5555, corresponding to a multiplication factor of 1.3333. This
scales the nominal ±0.75 signal to produce a full-scale output
signal of ±1.0 which is checked for overflow/underflow and
converted to twos complement or unipolar mode, as appro-
priate, before being output to the data register.
The actual gain, and the required scaling coefficient for zero
gain error, varies slightly from part to part and at different PGA
settings. The value downloaded into ADC0GN at power-on-
reset represents the scaling factor for a PGA gain = 4. There is
some level of gain error if this value is used at different PGA
settings. User code can run ADC calibrations and overwrite the
calibration coefficients to correct the gain error at the current
PGA setting.
In summary, the simplified ADC transfer function can be
described as
This equation is valid for the voltage/temperature channel ADC.
For the current channel ADC,
where K is dependent on the PGA gain setting and ADC mode.
For PGA gains of 4 and 32, the K factor is 1. For a PGA gain of
512, the K factor is 8.
ADC
ADC
OUT
OUT
=
=
⎡
⎢
⎣
⎡
⎢
⎣
V
V
IN
IN
V
V
×
×
REF
REF
PGA
PGA
−
−
K
ADCOF
×
ADCOF
⎤
⎥
⎦
×
ADCGN
⎤
⎥
⎦
×
ADCGN
ADCGN
ADCGN
NOM
NOM
Rev. B | Page 45 of 92
ADC CONFIGURATION
Fast Temperature Conversion Mode
The battery temperature can be derived through the on-chip
temperature sensor. By default, the time to a first valid (fully
settled) result after switching the ADC input from the voltage
to the temperature channel or from the temperature to the
voltage channel is three ADC conversion cycles with chop
mode turned off as shown in Figure 17.
A fast mode is provided on the temperature channel to
minimize the switching delay between voltage conversion and
temperature conversions as shown in Figure 18 and in Table 36.
A request for a fast temperature conversion is executed with a
delay of one ADC conversion. The fast temperature mode must
be cleared after the temperature measurement is available but
before a new temperature request.
Table 36. Fast Temperature Mode
Interrupt
1
2
3
4
5
6
7
8
Figure 18. Fast Temperature Mode, Chop Off ( ADCFLT = 0x07)
CHANNEL SWITCHING REQUEST
V
V
V
V
CHANNEL SWITCHING REQUEST
Figure 17. Default Temperature Mode, Chop Off
Valid Flags
I and V
I and V
I and V
I and T
I
I
I and V
I and V
V
V
V
V
T
T
V
T
V
T
V
User code
Voltage = ADC1DAT.
Voltage = ADC1DAT.
Set fast temperature request bit.
Voltage = ADC1DAT.
This data must be read for the next
temperature channel flag to be valid.
Temperature = ADC1DAT.
Clear fast temperature request bit.
Voltage = ADC1DAT.
Voltage = ADC1DAT.
T
V
V
V
V
V
V
V
V
V
V
V
V
V
I-ADC
SAMPLING
V/T-ADC
SAMPLING
I-ADC
INTERRUPT
VALID V/T
CONVERSION
I-ADC
SAMPLING
V/T-ADC
SAMPLING
I-ADC
INTERRUPT
VALID V/T
CONVERSION
ADuC7039