EVAL-AD7994CBZ Analog Devices Inc, EVAL-AD7994CBZ Datasheet - Page 18

• Manufacturer Part Number: EVAL-AD7994CBZ
• Description: BOARD EVALUATION FOR AD7994CBZ
• Manufacturer: Analog Devices Inc

Specifications of EVAL-AD7994CBZ

• Number Of Adc's: 1
• Number Of Bits: 12
• Sampling Rate (per Second): 188k
• Data Interface: Serial
• Inputs Per Adc: 4 Single Ended
• Input Range: 0 ~ 5.5 V
• Power (typ) @ Conditions: 7.7mW @ 188kSPS, 5.5 V
• Voltage Supply Source: Single
• Operating Temperature: -40°C ~ 125°C
• Utilized Ic / Part: AD7994
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD7993/AD7994
INTERNAL REGISTER STRUCTURE
The AD7993/AD7994 contain 17 internal registers (see
Figure 25) that are used to store conversion results, high and
low conversion limits, and information to configure and control
the device. Sixteen are data registers and one is an address
pointer register.
Each data register has an address that the address pointer
register points to when communicating with it. The conversion
result register is the only data register that is read only.
REGISTER
ADDRESS
POINTER
Figure 25. AD7993/AD7994 Register Structure
SERIAL BUS INTERFACE
RESULT REGISTER
CONFIGURATION
REGISTER CH1
REGISTER CH2
REGISTER CH2
REGISTER CH3
REGISTER CH4
ALERT STATUS
REGISTER CH3
REGISTER CH1
REGISTER CH1
REGISTER CH2
REGISTER CH3
REGISTER CH4
CYCLE TIMER
CONVERSION
REGISTER CH4
HYSTERESIS
HYSTERESIS
HYSTERESIS
DATA
DATA
HYSTERESIS
REGISTER
DATA
DATA
DATA
REGISTER
DATA
REGISTER
DATA
DATA
HIGH
HIGH
LOW
LOW
LOW
HIGH
LOW
HIGH
D
A
A
T
SDA
SCL
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ADDRESS POINTER REGISTER
Because it is the register to which the first data byte of every
write operation is written automatically, the address pointer
register does not have and does not require an address. The
address pointer register is an 8-bit register in which the 4 LSBs
are used as pointer bits to store an address that points to one of
the AD7993/AD7994’s data registers. The 4 MSBs are used as
command bits when operating in Mode 2 (see the Modes of
Operation section). The first byte following each write address
is the address of one of the data registers, which is stored in the
address pointer register and selects the data register to which
subsequent data bytes are written. Only the 4 LSBs of this
register are used to select a data register. On power-up, the
address pointer register contains all 0s, pointing to the
conversion result register.
Table 7. Address Pointer Register
C4
0
Table 8. AD7993/AD7994 Register Addresses
P3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
P2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
C3
0
P1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
C2
0
P0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Registers
Conversion Result Register (Read)
Alert Status Register (Read/Write)
Configuration Register (Read/Write)
Cycle Timer Register (Read/Write)
DATA
DATA
Hysteresis Reg CH1 (Read/Write)
DATA
DATA
Hysteresis Reg CH2 (Read/Write)
DATA
DATA
Hysteresis Reg CH3 (Read/Write)
DATA
DATA
Hysteresis Reg CH4 (Read/Write)
C1
0
LOW
HIGH
LOW
HIGH
LOW
HIGH
LOW
HIGH
Reg CH1 (Read/Write)
Reg CH2 (Read/Write)
Reg CH3 (Read/Write)
Reg CH4 (Read/Write)
Reg CH1 (Read/Write)
Reg CH2 (Read/Write)
Reg CH3 (Read/Write)
Reg CH4 (Read/Write)
P3
Register Select
P2
P1
P0