Datasheet

AD9523 Data Sheet
Rev. C | Page 40 of 60
CONTROL REGISTERS
CONTROL REGISTER MAP
Register addresses that are not listed in Table 31 are not used, and writing to those registers has no effect. Registers that are marked as
reserved should never have their values changed. When writing to registers with bits that are marked reserved, the user should take care
to always write the default value for the reserved bits.
Table 31. Control Register Map
Addr
(Hex)
Register
Name
(MSB)
Bit 7
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1
(LSB)
Bit 0
Default
Value
(Hex)
Serial Port Configuration
0x000
SPI mode
serial port
configuration
SDO
active
LSB first/
address
increment
Soft reset Reserved Reserved Soft reset
LSB first/
address
increment
SDO active 0x00
I
2
C mode
serial port
configuration
Reserved Reserved Soft reset Reserved Reserved Soft reset Reserved Reserved 0x00
0x004
Readback
control
Reserved Reserved Reserved Reserved Reserved Reserved Reserved
Read back
active registers
0x00
0x005
EEPROM
customer
version ID
EEPROM customer version ID[7:0] (LSB) 0x00
0x006 EEPROM customer version ID[15:8] (MSB) 0x00
Input PLL (PLL1)
0x010
PLL1 REFA
R divider
control
10-bit REFA R divider[7:0] (LSB) 0x00
0x011 Reserved
10-bit REFA R divider[9:8]
(MSB)
0x00
0x012
PLL1 REFB
R divider
control
10-bit REFB R divider[7:0] (LSB) 0x00
0x013 Reserved
10-bit REFB R divider[9:8]
(MSB)
0x00
0x014
PLL1 reference
test divider
Reserved Reserved REF_TEST divider 0x00
0x015 PLL1 reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved 0x00
0x016
PLL1 feedback
N divider
control
10-bit PLL1 feedback divider[7:0] (LSB) 0x00
0x017 Reserved
10-bit PLL1 feedback divider[9:8]
(MSB)
0x00
0x018
PLL1 charge
pump control
PLL1
charge
pump
tristate
PLL1 charge pump control 0x0C
0x019 Reserved Reserved Reserved
Enable SPI
control of
antibacklash
pulse width
Antibacklash
pulse width control
PLL1 charge pump mode 0x00
0x01A
PLL1
input receiver
control
REF_TEST
input
receiver
enable
REFB
differential
receiver
enable
REFA
differential
receiver
enable
REFB receiver
enable
REFA
receiver
enable
Input
REFA, REFB
receiver
power-
down
control
enable
OSC_IN
single-ended
receiver
mode enable
(CMOS mode)
OSC_IN
differential
receiver
mode enable
0x00
0x01B
REF_TEST,
REFA, REFB,
and ZD_IN
control
Reserved Reserved
Zero delay
mode
OSC_IN signal
feedback
for PLL1
ZD_IN
single-
ended
receiver
mode
enable
(CMOS
mode)
ZD_IN
differen.
receiver
mode
enable
REFB
single-ended
receiver
mode enable
(CMOS mode)
REFA
single-ended
receiver
mode enable
(CMOS mode)
0x00
0x01C
PLL1
miscellaneous
control
Enable
REFB
R divider
indepen.
division
control
OSC_CTRL
control
voltage to
VCC/2
when ref
clock fai
ls
Reserved Reference selection mode Reserved Reserved 0x00