Datasheet

AD9645 Data Sheet
Rev. 0 | Page 30 of 36
MEMORY MAP REGISTER TABLE
The AD9645 uses a 3-wire interface and 16-bit addressing and,
therefore, Bit 0 and Bit 7 in Register 0x00 are set to 0, and Bit 3
and Bit 4 are set to 1.
When Bit 5 in Register 0x00 is set high, the SPI enters a soft
reset, where all of the user registers revert to their default values
and Bit 2 is automatically cleared.
Table 16.
Addr.
(Hex) Parameter Name
Bit 7
(MSB) Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1
Bit 0
(LSB)
Default
Value
(Hex) Comments
Chip Configuration Registers
0x00 SPI port
configuration
0 = SDO
active
LSB first Soft reset 1 = 16-bit
address
1 = 16-bit
address
Soft reset LSB first 0 = SDO
active
0x18 Nibbles are
mirrored to
allow a given
register value
to perform
the same
function for
either MSB-
first or LSB-
first mode.
0x01 Chip ID (global) 8-bit chip ID, Bits[7:0]
AD9645 0x8B = dual, 14-bit, 80 MSPS/125 MSPS, serial LVDS
0x8B Unique chip
ID used to
differentiate
devices;
read only.
0x02 Chip grade
(global)
Open Speed grade ID, Bits[6:4]
100 = 80 MSPS
110 = 125 MSPS
Open Open Open Open Unique speed
grade ID used
to differentiate
graded
devices;
read only.
Device Index and Transfer Registers
0x05 Device index Open Open Clock
Channel
DCO
Clock
Channel
FCO
Open Open Data
Channel B
Data
Channel A
0x33 Bits are set to
determine
which device
on chip
receives the
next write
command.
Default is all
devices on
chip.
0xFF Transfer Open Open Open Open Open Open Open Initiate
override
0x00 Set
resolution/
sample rate
override.
Global ADC Function Registers
0x08 Power modes
(global)
Open Open Open Open Open Open Power mode
00 = chip run
01 = full power-down
10 = standby
11 = reset
0x00 Determines
various
generic
modes of chip
operation.
0x09 Clock (global) Open Open Open Open Open Open Open Duty cycle
stabilizer
0 = off
1 = on
0x00 Turns
duty cycle
stabilizer on
or off.
0x0B Clock divide
(global)
Open Open Open Open Open Clock divide ratio[2:0]
000 = divide by 1
001 = divide by 2
010 = divide by 3
011 = divide by 4
100 = divide by 5
101 = divide by 6
110 = divide by 7
111 = divide by 8
0x00
0x0C Enhancement
control
Open Open Open Open Open Chop
mode
0 = off
1 = on
Open Open 0x00 Enables/
disables
chop mode.