47.1 Description

The Multi Channel Serial Peripheral Interface (MCSPI) circuit is a full-featured SPI module with specific enhancements to ease interfacing with external devices such as MCP3910 24-bit ADC.

A client device is selected when the host asserts its NSS signal. If multiple client devices exist, the host generates a separate client select signal for each client (NPCS).

The SPI system consists of two data lines and two control lines:

• Host Out Client In (MOSI)—This data line supplies the output data from the host shifted into the input(s) of the client(s).
• Host In Client Out (MISO)—This data line supplies the output data from a client to the input of the host. There may be no more than one client transmitting data during any particular transfer.
• Serial Clock (SPCK)—This control line is driven by the host and regulates the flow of the data bits. The host can transmit data at a variety of baud rates; there is one SPCK pulse for each bit that is transmitted.
• Client Select (NSS)—This control line allows clients to be turned on and off by hardware.