Datasheet
Data Sheet AD9637
Rev. A | Page 31 of 40
MEMORY MAP REGISTER TABLE
The AD9637 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 Register 0x00, Bit 5 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 17. Memory Map Register Table
Reg.
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 The nibbles
are mirrored
so that LSB or
MSB first
mode registers
correctly. The
default for
the ADCs is
16-bit mode.
0x01 Chip ID (global) 8-bit chip ID, Bits[7:0]
AD9637 0x93 = octal 12-bit 40 MSPS/80 MSPS serial LVDS
Read
only
0x93
Unique chip ID
that is used to
differentiate
devices; read
only.
0x02 Chip grade
(global)
Open Speed grade ID, Bits[6:4]
001 = 40 MSPS
100 = 80 MSPS
Open Open Open Open Read
only
Unique speed
grade ID that
is used to
differentiate
graded
devices; read
only.
Device Index and Transfer Registers
0x04 Device Index 2 Open Open Open Open Data
Channel H
Data
Channel G
Data
Channel F
Data
Channel E
0xF Bits are set to
determine
which device
on chip
receives the
next write
command.
The default is
all devices on
chip.
0x05 Device Index 1 Open Open Clock
Channel
DCO
Clock
Channel
FCO
Data
Channel D
Data
Channel C
Data
Channel B
Data
Channel A
0x3F Bits are set
to determine
which device
on chip
receives the
next write
command.
The 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 Functions
0x08 Power modes
(global)
Open Open External
power-
down
pin
function
0 = full
power-
down
1 =
standby
Open Open Open Internal power-down
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
0x01 Turns duty
cycle
stabilizer on
or off.