adc121c027cimkx National Semiconductor Corporation, adc121c027cimkx Datasheet - Page 18

• Manufacturer Part Number: adc121c027cimkx
• Description: I2c-compatible, 12-bit Analog-to-digital Converter Adc With Alert Function
• Manufacturer: National Semiconductor Corporation

www.national.com
1.6.4 Configuration Register
Pointer Address 02h (Read/Write)
Default Value: 00h
Cycle Time [2:0]
Bits
7:5
4
3
2
1
0
D7
D6
Name
Cycle Time
Alert Hold
Alert Flag Enable
Alert Pin Enable
Reserved
Polarity
D5
Alert
Hold
D4
Enable
Alert
Flag
D3
Description
Configures Automatic Conversion mode. When these bits are set to zeros, the automatic
conversion mode is disabled. This is the case at power-up.
When these bits are set to a non-zero value, the ADC will begin operating in automatic conversion
mode. (See Section 1.9). The Cycle Time table shows how different values provide various
conversion intervals.
0: Alerts will self-clear when the measured voltage moves within the limits by more than the
hysteresis register value.
1: Alerts will not self-clear and are only cleared when a one is written to the alert high flag or the
alert low flag in the Alert Status register.
0: Disables alert status bit [D15] in the Conversion Result register.
1: Enables alert status bit [D15] in the Conversion Result register.
0: Disables the ALERT output pin. The ALERT output will TRI-STATE when the pin is disabled.
1: Enables the ALERT output pin.
*This bit does not apply to the ADC121C027.
Always reads zeros. Zeros must be written to these bits.
This bit configures the active level polarity of the ALERT output pin.
0: Sets the ALERT pin to active low.
1: Sets the ALERT pin to active high.
*This bit does not apply to the ADC121C027.
Enable
Alert
Pin
D2
D1
0
Polarity
D0
18
D7
0
0
0
0
1
1
1
1
Cycle Time[2:0]
D6
0
0
1
1
0
0
1
1
D5
0
1
0
1
0
1
0
1
Mode Disabled
T
T
T
T
T
Conversion
T
T
convert
convert
convert
convert
convert
convert
convert
Interval
x 1024
x 2048
x 128
x 256
x 512
x 32
x 64
Typical
(kSPS)
f
convert
13.5
6.7
3.4
1.7
0.9
0.4
27
0