Microchip Technology TSSOP20EV Data Sheet
© 2009 Microchip Technology Inc.
DS22233A-page 43
MCP434X/436X
6.0
SERIAL INTERFACE (SPI)
The MCP43XX devices support the SPI serial protocol.
This SPI operates in the slave mode (does not
generate the serial clock).
This SPI operates in the slave mode (does not
generate the serial clock).
The SPI interface uses up to four pins. These are:
• CS - Chip Select
• SCK - Serial Clock
• SDI - Serial Data In
• SDO - Serial Data Out
• SCK - Serial Clock
• SDI - Serial Data In
• SDO - Serial Data Out
Typical SPI Interface is shown in
. In the SPI
interface, the Master’s Output pin is connected to the
Slave’s Input pin and the Master’s Input pin is
connected to the Slave’s Output pin.
Slave’s Input pin and the Master’s Input pin is
connected to the Slave’s Output pin.
The MCP4XXX SPI’s module supports two (of the four)
standard SPI modes. These are Mode 0,0 and 1,1.
The SPI mode is determined by the state of the SCK
pin (V
standard SPI modes. These are Mode 0,0 and 1,1.
The SPI mode is determined by the state of the SCK
pin (V
IH
or V
IL
) on the when the CS pin transitions from
inactive (V
IH
) to active (V
IL
or V
IHH
).
All SPI interface signals are high-voltage tolerant.
FIGURE 6-1:
Typical SPI Interface Block Diagram.
SDI
SDO
MCP4XXX
SDO
SDI
SCK
SCK
(Master Out - Slave In (MOSI))
(Master In - Slave Out (MISO))
Host
Controller
Typical SPI Interface Connections
CS
I/O
(1)
Note 1: If High voltage commands are desired, some type of external circuitry needs to be implemented.