MCP42050-I/TS Microchip Technology, MCP42050-I/TS Datasheet - Page 22

• Manufacturer Part Number: MCP42050-I/TS
• Description: Single/Dual Digital Potentiometer with SPI Interface
• Manufacturer: Microchip Technology

MCP41XXX/42XXX
5.8
It is possible to operate the devices in SPI modes 0,0
and 1,1. The only difference between these two modes
is that, when using mode 1,1, the clock idles in the high
state, while in mode 0,0, the clock idles in the low state.
In both modes, data is clocked into the devices on the
rising edge of SCK and data is clocked out the SO pin
once the falling edge of SCK. Operations using mode
0,0 are shown in Figure 5-1. The example in
Figure 5-5 shows mode 1,1.
FIGURE 5-5:
DS11195C-page 22
SCK
CS†
SO‡
SI
Using the MCP41XXX/42XXX in
SPI Mode 1,1
†
‡
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.
X
1
Don’t
Care
Bits
Timing Diagram for SPI Mode 1,1 Operation.
2
X
COMMAND BYTE
Command
C1
3
Data is always latched in
on the rising edge of SCK.
Bits
C0
4
First 16 bits Shifted out will always be zeros
5
X
Don’t
Care
Bits
X
6
P1* P0
Channel
7
Select
Bits
8
D7
9
10
D6
11
D5
Data is always clocked out the SO
pin after the falling edge of SCK.
New Register Data
DATA BYTE
12
D4
13
D3
14
D2
15
D1
16
D0
X
2003 Microchip Technology Inc.
Data Registers are
loaded on rising
edge of CS. Shift
register is loaded
with zeros at this time.
SO pin will always
drive low when CS
goes high.