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AD6655
MEMORY MAP REGISTER TABLE
All address and bit locations that are not included in Table 29 are not currently supported for this device.
Rev. 0 | Page 51 of 84
Table 29. Memory Map Registers
Addr.
(Hex)
Chip Configuration Registers
0x00
SPI Port
Configuration
(Global)
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
(Hex)
Default
Notes/
Comments
0
LSB first
Soft reset
1
1
Soft
reset
LSB first
0
0x18
The nibbles
are mirrored
so that
LSB- first or
MSB-first
mode
registers
correctly,
regardless of
shift mode
Default is
unique chip
ID, different
for each
device; this is
a read-only
register
Speed grade
ID used to
differentiate
devices; this
is a read-only
register
0x01
Chip ID
(Global)
8-bit Chip ID[7:0]
(AD6655 = 0x0D)
(default)
0x0D
0x02
Chip Grade
(Global)
Open
Open
Speed Grade ID[4:3]
00 = 150 MSPS
01 = 125 MSPS
10 = 105 MSPS
11 = 80 MSPS
Open
Open
Open
Open
Channel Index and Transfer Registers
0x05
Channel
Index
Open
Open
Open
Open
Open
Open
Data
Channel B
(default)
Data
Channel A
(default)
0x03
Bits are set to
determine
which device
on chip
receives the
next write
command;
applies to
local registers
Synchronously
transfers data
from the
master shift
register to
the slave
0xFF
Transfer
Open
Open
Open
Open
Open
Open
Open
Transfer
0x00
ADC Function Registers
0x08
Power Modes
Open
Open
External
power-
down pin
function
(global)
0 = pdwn
1 = stndby
Open
Open
Open
Open
Internal power-down
mode (local)
00 = normal operation
01 = full power-down
10 = standby
11 = normal operation
0x00
Determines
various
generic
modes of chip
operation
0x09
Global Clock
(Global)
Open
Open
Open
Open
Open
Open
Duty cycle
stabilize
(default)
0x01
0x0B
Clock Divide
(Global)
Open
Open
Open
Open
Open
Clock divide ratio
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
Clock divide
values other
than 000
automatically
activate
duty cycle
stabilization