ADS7830I Burr-Brown Corporation, ADS7830I Datasheet - Page 11

• Manufacturer Part Number: ADS7830I
• Description: 8-Bit/ 8-Channel Sampling ANALOG-TO-DIGITAL CONVERTER with I2C Interface
• Manufacturer: Burr-Brown Corporation

ADS7830
Address Byte
The address byte is the first byte received following the
START condition from the master device. The first five bits
(MSBs) of the slave address are factory pre-set to 10010.
The next two bits of the address byte are the device select
bits, A1 and A0. Input pins (A1-A0) on the ADS7830 deter-
mine these two bits of the device address for a particular
ADS7830. A maximum of four devices with the same pre-set
code can therefore be connected on the same bus at one
time.
The A1-A0 Address Inputs can be connected to V
ground. The device address is set by the state of these pins
upon power-up of the ADS7830.
The last bit of the address byte (R/W) defines the operation
to be performed. When set to a “1” a read operation is
selected; when set to a “0” a write operation is selected.
Following the START condition the ADS7830 monitors the
SDA bus, checking the device type identifier being transmit-
ted. Upon receiving the 10010 code, the appropriate device
select bits, and the R/W bit, the slave device outputs an
acknowledge signal on the SDA line.
TABLE I. Channel Selection Control Addressed by Command BYTE.
MSB
SBAS302
1
SD
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
6
0
C2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
5
0
C1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
4
1
C0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
3
0
A1
2
CH0
+IN
–IN
+IN
—
—
—
—
—
—
—
—
—
—
—
—
—
A0
1
DD
CHANNEL SELECTION CONTROL
CH1
–IN
+IN
+IN
or digital
—
—
—
—
—
—
—
—
—
—
—
—
—
LSB
R/W
www.ti.com
CH2
+IN
–IN
+IN
—
—
—
—
—
—
—
—
—
—
—
—
—
Command Byte
The ADS7830’s operating mode is determined by a com-
mand byte which is illustrated above.
SD: Single-Ended/Differential Inputs
See Table I for Truth Table.
POWER-DOWN SELECTION
INITIATING CONVERSION
Provided the master has write-addressed it, the ADS7830
turns on the A/D converter’s section and begins conversions
when it receives BIT 4 of the command byte shown in the
Command Byte. If the command byte is correct, the ADS7830
will return an ACK condition.
C2 - C0: Channel Selections
PD1 - 0: Power-Down Selection
PD1
MSB
0: Differential Inputs
1: Single-Ended Inputs
SD
0
0
1
1
CH3
–IN
+IN
+IN
—
—
—
—
—
—
—
—
—
—
—
—
—
X: Unused
PD0
0
1
0
1
C2
6
CH4
+IN
+IN
DESCRIPTION
Power Down Between A/D Converter Conversions
Internal Reference OFF and A/D Converter ON
Internal Reference ON and A/D Converter OFF
Internal Reference ON and A/D Converter ON
–IN
—
—
—
—
—
—
—
—
—
—
—
—
—
C1
5
CH5
+IN
+IN
–IN
—
—
—
—
—
—
—
—
—
—
—
—
—
C0
4
PD1
CH6
+IN
–IN
+IN
—
—
—
—
—
—
—
—
—
—
—
—
—
3
PD0
2
CH7
–IN
+IN
+IN
—
—
—
—
—
—
—
—
—
—
—
—
—
X
1
COM
–IN
–IN
–IN
–IN
–IN
–IN
–IN
–IN
—
—
—
—
—
—
—
—
LSB
X
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