LS_Synchronous serial peripheral (SSP)
RM0082
280/844
Doc ID 018672 Rev 1
13.6.7 SSPSR
register
SSPSR is a read only register that contains bits that indicates the FIFO fill status and the
SSP busy status.
13.6.8 SSPCPSR
register
SSPCPSR is the clock prescale register and specifies the division factor by which the input
SSPCLK must be internally divided before further use.
The value programmed into this register must be an even number between 2 to 254. The
least significant bit of the programmed number is hard-coded to zero. If an odd number is
written to this register, data read back from this register has the least significant bit as zero.
The SSPCPSR bit assignments are given in
Table 215.
SSPDR register bit assignments
Bit
Name
Type
Description
[15:00] DATA
R/W
Transmit/receive FIFO:
Read = Receive FIFO
Write = Transmit FIFO
You must right justify data when the SSP is programmed for a data size
that is less then 16 bits. Unused bits are ignored by transmit logic. The
receive logic automatically right justifies.
Table 216.
SSPSR register bit assignments
Bit
Name
Type
Description
[15:05]
-
-
Reserved, read unpredictable, should be written as 0
[04]
BSY
RO
SSP busy flag:
1’b0 = SSP is idle
1’b1 = SSP is currently transmitting or receiving a frame
[03]
RFF
RO
Receive FIFO Full:
1’b0 = receive FIFO is not full
1’b1 = Receive FIFO is full
[02]
RNE
RO
Receive FIFO not empty:
1’b0 = Receive FIFO is empty
1’b1 = receive FIFO is not empty
[01]
TNF
RO
Transmit FIFO not full:
1’b0 = Transmit FIFO is full
1’b1 = transmit FIFO is not full
[00]
TFE
RO
Transmit FIFO empty:
1’b0 = Transmit FIFO is not empty
1’b1 = transmit FIFO is empty