DSPIC30F5015_11 Datasheet, PDF (111/234 Pages) Microchip Technology – High-Performance, 16-bit Digital Signal Controllers

16.2 Framed SPI Support
The module supports a basic framed SPI protocol in
Master or Slave mode. The control bit FRMEN enables
framed SPI support and causes the SSx pin to perform
the frame synchronization pulse (FSYNC) function.
The control bit, SPIFSD, determines whether the SSx
pin is an input or an output (i.e., whether the module
receives or generates the frame synchronization
pulse). The frame pulse is an active-high pulse for a
single SPI clock cycle. When frame synchronization is
enabled, the data transmission starts only on the
subsequent transmit edge of the SPI clock.
16.3 Slave Select Synchronization
The SSx pin allows a Synchronous Slave mode. The
SPI must be configured in SPI Slave mode, with SSx
pin control enabled (SSEN = 1). When the SSx pin is
low, transmission and reception are enabled, and the
SDOx pin is driven. When SSx pin goes high, the SDOx
pin is no longer driven. Also, the SPI module is re-
synchronized, and all counters/control circuitry are
reset. Therefore, when the SSx pin is asserted low
again, transmission/reception will begin at the MSb,
even if SSx had been deasserted in the middle of a
transmit/receive.
dsPIC30F5015/5016
16.4 SPI Operation During CPU Sleep
Mode
During Sleep mode, the SPI module is shutdown. If the
CPU enters Sleep mode while an SPI transaction is in
progress, then the transmission and reception is
aborted.
The transmitter and receiver will stop in Sleep mode.
However, register contents are not affected by
entering or exiting Sleep mode.
16.5 SPI Operation During CPU Idle
Mode
When the device enters Idle mode, all clock sources
remain functional. The SPISIDL bit (SPIxSTAT<13>)
selects if the SPI module will stop or continue on Idle.
If SPISIDL = 0, the module will continue to operate
when the CPU enters Idle mode. If SPISIDL = 1, the
module will stop when the CPU enters Idle mode.
© 2011 Microchip Technology Inc.
DS70149E-page 111