ADN2850 Analog Devices, Inc., ADN2850 Datasheet - Page 15

• Manufacturer Part Number: ADN2850
• Description: Nonvolatile Memory, Dual 1024 Position Programmable Resistors
• Manufacturer: Analog Devices, Inc.

PROGRAMMING EXAMPLES
The following programming examples illustrate the typical sequence
of events for various features of the ADN2850. Users should refer
to Table II for the instructions and data-word format. The instruc-
tion numbers, addresses, and data appearing at SDI and SDO pins
are displayed in hexadecimal format in the following examples.
SDI
B00100
B10200
SDI
B00100
E0XXXX
E0XXXX
20XXXX
EEMEM values for RDACs can be restored by: Power-On,
Strobing PR pin or Programming shown below.
SDI
10XXXX
00XXXX
8XXXXX
REV. B
Table XI. Restoring EEMEM Values to RDAC Registers
Table X. Incrementing RDAC Followed by Storing
the Wiper Setting to EEMEM
H
H
H
H
H
H
H
H
H
SDO
XXXXXX
B00100
E0XXXX
XXXXXX
SDO
XXXXXX
B00100
SDO
XXXXXX
100100
00XXXX
Table IX. Scratch Pad Programming
H
H
H
H
H
H
H
H
H
Action
Loads data 100
Wiper W1 moves to 1/4 full-scale position.
Increments RDAC1 register by one to 101
Increments RDAC1 register by one to 102
Saves RDAC1 data into EEMEM1
Optionally tie WP to GND to protect
EEMEM values
Repeat the increment command –
(E0XXXX
position is reached
Action
Restores EEMEM1 value to RDAC1
register.
NOP. Recommended step to minimize
power consumption.
Reset EEMEM1 and EEMEM2
values to RDAC1 and RDAC2 registers
respectively.
Action
Loads data 100
Wiper W1 moves to 1/4 full-scale
position.
Loads data 200
Wiper 2 moves to 1/2 full-scale position.
H)
until desired wiper
H
into RDAC1 register,
H
H
into RDAC2 register,
into RDAC1 register,
H
H
.
.
–15–
SDI
C0XXXX
C1XXXX
SDI
32AAAA
335555
Table XIV. Reading Back Data From Various Memory Locations
SDI
92XXXX
00XXXX
SDI
B00200
C0XXXX
A0XXXX
XXXXXX
Analog Devices offers a user-friendly ADN2850EVAL evaluation
kit that can be controlled by a personal computer through the printer
port. The driving program is self-contained, so no programming
languages or skills are needed.
Table XII. Using Left Shift by One to Increment 6 dB Steps
Table XIII. Storing Additional User Data in EEMEM
H
H
H
H
H
H
H
H
H
H
Table XV. Reading Back Wiper Setting
SDO
XXXXXX
C0XXXX
SDO
XXXXXX
32AAAA
SDO
XXXXXX
92AAAA
SDO
XXXXXX
B00200
C0XXXX
A003FF
H
H
H
H
H
H
H
H
H
H
Action
Moves wiper 1 to double the present
data contained in RDAC1 register.
Moves wiper 2 to double the present
data contained in RDAC2 register.
Action
Stores data AAAA
location USER1. (Allowable to address
in 13 locations with maximum 16 bits
of data).
Stores data 5555
location USER2. (Allowable to address
in 13 locations with maximum 16 bits
of data).
Action
Prepares data read from USER1
location.
NOP instruction 0 sends 24-bit word
out of SDO where the last 16 bits
contain the contents of USER1 location.
NOP command ensures device returns
to idle power dissipation state.
Action
Sets RDAC1 to midscale.
Doubles RDAC1 from midscale to
full-scale.
Prepares reading wiper setting from
RDAC1 register.
Readback full-scale value from RDAC1
register.
H
H
into spare EEMEM
ADN2850
into spare EEMEM