MAX5422 MAXIM [Maxim Integrated Products], MAX5422 Datasheet - Page 8

• Manufacturer Part Number: MAX5422
• Description: 256-Tap, Nonvolatile, SPI-Interface, Digital Potentiometers
• Manufacturer: MAXIM [Maxim Integrated Products]

(CS), data clock (SCLK), and data in (DIN). Drive CS
low to enable the serial interface and clock data syn-
chronously into the shift register on each SCLK rising
edge.
The WRITE commands (C1, C0 = 00 or 01) require 16
clock cycles to clock in the command and data (Figure
2a). The COPY commands (C1, C0 = 10, 11) can use
either eight clock cycles to transfer the command bits
(Figure 2b) or 16 clock cycles with 8 data bits that are
disregarded by the device (Figure 2a).
256-Tap, Nonvolatile, SPI-Interface,
Digital Potentiometers
Table 1. Register Map
Figure 2. Digital-Interface Format
8
Bit name
Write wiper register
Write NV register
Copy wiper register to NV
register
Copy NV register to wiper
register
_______________________________________________________________________________________
CLOCK EDGE
A) 16-BIT COMMAND/DATA WORD
B) 8-BIT COMMAND WORD
SCLK
SCLK
DIN
DIN
CS
CS
1
1
—
1
0
0
0
0
2
2
—
2
0
0
0
0
C1
C1
3
3
C1
3
0
0
1
1
C0
C0
4
4
C0
4
0
1
0
1
5
5
—
5
0
0
0
0
6
6
7
—
7
6
0
0
0
0
8
8
After loading data into the shift register, drive CS high
to latch the data into the appropriate potentiometer
control register and disable the serial interface. Keep
CS low during the entire serial-data stream to avoid
corruption of the data.
The serial-data timing for the potentiometer is shown in
Figures 1 and 2.
—
7
0
0
0
0
D7
9
—
8
0
0
0
0
D6
10
D7
D7
D7
—
—
9
D5
11
D6
D6
D6
10
—
—
12
D4
D5
D5
D5
11
—
—
13
D3
D4
D4
D4
12
—
—
D2
14
D1
15
D3
D3
D3
13
—
—
16
D0
D2
D2
D2
14
—
—
D1
D1
D1
15
—
—
D0
D0
D0
16
—
—