ADUC836 Analog Devices, ADUC836 Datasheet - Page 21

• Manufacturer Part Number: ADUC836
• Description: Precision Analog Microcontroller: 1MIPS 8052 MCU + 62kB Flash + Dual 16-Bit ADC + 12-Bit DAC
• Manufacturer: Analog Devices

Specifications of ADUC836

• Mcu Core: 8052
• Mcu Speed (mips): 1
• Sram (bytes): 2304Bytes
• Gpio Pins: 34
• Adc # Channels: 4
• Other: PWM

ICON (Current Sources Control Register)
The icon SFR is used to control and configure the various excitation and burnout current source options available on-chip.
SFR Address
Power-On Default Value
Bit Addressable
Bit
7
6
5
4
3
2
1
0
*Both current sources can be enabled to the same external pin, yielding a 400 A current source.
SF (Sinc Filter Register)
The number in this register sets the decimation factor and thus
the output update rate for the primary and auxiliary ADCs. This
SFR cannot be written by user software while either ADC is active.
The update rate applies to both primary and auxiliary ADCs and
is calculated as follows:
where:
The allowable range for SF is 0DH to FFH. Examples of SF
values and corresponding conversion update rates (f
version times (t
REV. A
Name
–––
BO
ADC1IC
ADC0IC
I2PIN*
I1PIN*
I2EN
I1EN
f
f
SF = Decimal Value of SF Register
ADC
MOD
ADC
= ADC Output Update Rate
= Modulator Clock Frequency = 32.768 kHz
) are shown in Table VIII.The power-on default
f
ADC
Description
Reserved for Future Use
Burnout Current Enable Bit.
Set by user to enable both transducer burnout current sources in the primary ADC signal paths.
Cleared by the user to disable both transducer burnout current sources.
Auxiliary ADC Current Correction Bit. Set by user to allow scaling of the auxiliary ADC by an internal current
source calibration word.
Primary ADC Current Correction Bit.
Set by user to allow scaling of the primary ADC by an internal current source calibration word.
Current Source-2 Pin Select Bit.
Set by user to enable current source-2 (200 A) to external Pin 3 (P1.2/DAC/IEXC1).
Cleared by user to enable current source-2 (200 A) to external Pin 4 (P1.3/AIN5/IEXC2).
Current Source-1 Pin Select Bit.
Set by user to enable current source-1 (200 A) to external Pin 4 (P1.3/AIN5/IEXC2).
Cleared by user to enable current source-1 (200 A) to external Pin 3 (P1.2/DAC/IEXC1).
Current Source-2 Enable Bit.
Set by user to turn on excitation current source-2 (200 A).
Cleared by user to turn off excitation current source-2 (200 A).
Current Source-1 Enable Bit.
Set by user to turn on excitation current source-1 (200 A).
Cleared by user to turn off excitation current source-1 (200 A).
=
1
3
×
8
×
1
SF
D5H
00H
No
×
f
MOD
Table IX. ICON SFR Bit Designations
ADC
) and con-
–21–
value for the SF Register is 45H, resulting in a default ADC update
rate of just under 20 Hz. Both ADC inputs are chopped to mini-
mize offset errors, which means that the settling time for a single
conversion, or the time to a first conversion result in Continuous
Conversion mode, is 2  t
tion cycles will be carried out automatically with a maximum, i.e.,
FFH, SF value to ensure optimum calibration performance. Once
a calibration cycle has completed, the value in the SF Register will
be that programmed by user software.
SF(dec)
13
69
255
Table VIII. SF SFR Bit Designations
SF(hex)
0D
45
FF
ADC
. As mentioned earlier, all calibra-
f
105.3
19.79
5.35
ADC
(Hz)
ADuC836
t
9.52
50.34
186.77
ADC
(ms)