
XC878CLM
Functional Description
Data Sheet
91
V1.1, 2009-08
3.16
High-Speed Synchronous Serial Interface
The High-Speed Synchronous Serial Interface (SSC) supports full-duplex and
half-duplex synchronous communication. The serial clock signal can be generated by
the SSC internally (master mode), using its own 16-bit baud-rate generator, or can be
received from an external master (slave mode). Data width, shift direction, clock polarity
and phase are programmable. This allows communication with SPI-compatible devices
or devices using other synchronous serial interfaces.
Features
Master and slave mode operation
– Full-duplex or half-duplex operation
Transmit and receive buffered
Flexible data format
– Programmable number of data bits: 2 to 8 bits
– Programmable shift direction: LSB or MSB shift first
– Programmable clock polarity: idle low or high state for the shift clock
– Programmable clock/data phase: data shift with leading or trailing edge of the shift
clock
Variable baud rate
Compatible with Serial Peripheral Interface (SPI)
Interrupt generation
– On a transmitter empty condition
– On a receiver full condition
– On an error condition (receive, phase, baud rate, transmit error)
Data is transmitted or received on lines TXD and RXD, which are normally connected to
the pins MTSR (Master Transmit/Slave Receive) and MRST (Master Receive/Slave
Transmit). The clock signal is output via line MS_CLK (Master Serial Shift Clock) or input
via line SS_CLK (Slave Serial Shift Clock). Both lines are normally connected to the pin
SCLK. Transmission and reception of data are double-buffered.
Figure 27 shows the block diagram of the SSC.