AD9627-11_15 Datasheet, PDF (40/72 Pages) Analog Devices – 11-Bit, 105 MSPS/150 MSPS, 1.8 V Dual Analog-to-Digital Converter

AD9627-11
MEMORY MAP
READING THE MEMORY MAP REGISTER TABLE
Each row in the memory map register table has eight bit loca-
Logic Levels
An explanation of logic level terminology follows:
tions. The memory map is roughly divided into four sections: the
 “Bit is set” is synonymous with “bit is set to Logic 1” or
chip configuration registers (Address 0x00 to Address 0x02);
“writing Logic 1 for the bit.”
the channel index and transfer registers (Address 0x05 and
 “Clear a bit” is synonymous with “bit is set to Logic 0” or
Address 0xFF); the ADC functions registers, including setup,
“writing Logic 0 for the bit.”
control, and test (Address 0x08 to Address 0x25); and the digital
feature control registers (Address 0x100 to Address 0x11B).
Transfer Register Map
The memory map register table (see Table 22) documents the
Address 0x08 to Address 0x18 are shadowed. Writes to these
default hexadecimal value for each hexadecimal address shown.
The column with the heading Bit 7 (MSB) is the start of the
default hexadecimal value given. For example, Address 0x18, the
VREF select register, has a hexadecimal default value of 0xC0.
This means that Bit 7 = 1, Bit 6 = 1, and the remaining bits are 0s.
E _{This setting is the default reference selection setting. The default}
value uses a 2.0 V p-p reference. For more information on this
function and others, see Application Note AN-877, Interfacing to
T _{High Speed ADCs via SPI. This document details the functions}
controlled by Register 0x00 to Register 0xFF. The remaining
registers, from Register 0x100 to Register 0x11B, are documented
E ^{in the Memory Map Register Description section.}
Open Locations
All address and bit locations that are not included in Table 22
L are not currently supported for this device. Unused bits of a
valid address location should be written with 0s. Writing to these
locations is required only when part of an address location is
open (for example, Address 0x18). If the entire address location
O ^{is open (for example, Address 0x13), this address location should}
not be written.
Default Values
S ^{After the AD9627-11 is reset, critical registers are loaded with}
default values. The default values for the registers are given in
OB ^{the memory map register table, Table 22.}
addresses do not affect part operation until a transfer command
is issued by writing 0x01 to Address 0xFF, setting the transfer bit.
This allows these registers to be updated internally and simulta-
neously when the transfer bit is set. The internal update takes
place when the transfer bit is set, and the bit autoclears.
Channel-Specific Registers
Some channel setup functions, such as the signal monitor thresh-
olds, can be programmed differently for each channel. In these
cases, channel address locations are internally duplicated for
each channel. These registers and bits are designated in Table 22
as local. These local registers and bits can be accessed by setting
the appropriate Channel A or Channel B bits in Register 0x05. If
both bits are set, the subsequent write affects the registers of both
channels. In a read cycle, only Channel A or Channel B should be
set to read one of the two registers. If both bits are set during an
SPI read cycle, the part returns the value for Channel A. Registers
and bits designated as global in Table 22 affect the entire part or
the channel features where independent settings are not allowed
between channels. The settings in Register 0x05 do not affect
the global registers and bits.
Rev. B | Page 40 of 72