MCP41050-ISN Datasheet, PDF (18/32 Pages) Microchip Technology – Single/Dual Digital Potentiometer with SPI™ Interface

MCP41XXX/42XXX
CS†
SCK
SI
SO‡
FIGURE 5-1:
Data is always latched
in on the rising edge
of SCK.
Data is always clocked out
of the SO pin after the
falling edge of SCK.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
COMMAND Byte
Data Byte
Don’t
Don’t
Care Command Care
Bits
Bits
Bits
Channel
Select
Bits
New Register Data
X X C1 C0 X X P1* P0 D7 D6 D5 D4 D3 D2 D1 D0
Data Registers are
loaded on rising
edge of CS. Shift
register is loaded
with zeros at this time.
First 16 bits shifted out will always be zeros
SO pin will always
drive low when CS
goes high.
X
† There must always be multiples of 16 clocks while CS is low or commands will abort.
‡ The serial data out pin (SO) is only available on the MCP42XXX device.
* P1 is a ‘don’t care’ bit for the MCP41XXX.
Timing Diagram for Writing Instructions or Data to a Digital Potentiometer.
COMMAND BYTE
X X C1 C0 X X P1* P0
Command Potentiometer
Selection Selection
Bits
Bits
C1 C0 Command
Command Summary
0 0 None
No Command will be executed.
0 1 Write Data Write the data contained in Data Byte to the
potentiometer(s) determined by the potenti-
ometer selection bits.
1 0 Shutdown Potentiometer(s) determined by potentiome-
ter selection bits will enter Shutdown Mode.
Data bits for this command are ‘don’t cares’.
1 1 None
No Command will be executed.
FIGURE 5-2:
Command Byte Format.
P1* P0
Potentiometer Selections
0 0 Dummy Code: Neither Potentiometer
affected.
0 1 Command executed on
Potentiometer 0.
1 0 Command executed on
Potentiometer 1.
1 1 Command executed on both
Potentiometers.
DS11195C-page 18
 2003 Microchip Technology Inc.