Intel PXA255 - Manual (Page 567)

Intel® PXA255 Processor Developer’s Manual 16-27
Network SSP Serial Port
19 TINT
RECEIVER TIME-OUT INTERRUPT:
Indicates that the receive FIFO has been idle (no samples received) for the period of time
defined by the value programmed within SSTO. This interrupt can be masked by
SSCR1[TINTE].
Write one to clear this bit.
0 – No Receiver Time-out pending
1 – Receiver Time-out pending
18:16 — reserved
15:12 RFL
RECEIVE FIFO LEVEL:
The number of valid entries (minus 1) currently in the receive FIFO.
When the value of 0xF is read, the FIFO is either empty or full and programmers must refer to
RNE.
11:8 TFL
TRANSMIT FIFO LEVEL:
Number of valid entries (minus 1) currently in the transmit FIFO.
When the value of 0x0 is read, the FIFO is either empty or full and programmers must refer to
TNF.
7 ROR
RECEIVE FIFO OVERRUN:
Indicates that the Receive logic attempted to place data into the receive FIFO after it had been
completely filled. When new data is received, ROR is asserted and the newly received data is
discarded. This process is repeated for all new data received until at least one empty FIFO entry
exists.
When set, an interrupt is generated to the CPU that cannot be locally masked by any SSP
register bit. The setting of ROR does not generate any DMA service request. Clearing this bit
resets its interrupt request.
Write one to clear this bit.
0 – Receive FIFO has not experienced an overrun
1 – Attempted data write to full receive FIFO, request Interrupt
6 RFS
RECEIVE FIFO SERVICE REQUEST:
Indicates that the receive FIFO requires service to prevent an overrun. RFS is set when the
number of valid entries in the receive FIFO is equal to or greater than the receive FIFO trigger
threshold. It is cleared when it has fewer entries than the trigger threshold value. When RFS is
set, an Interrupt is generated when SSCR1[RIE] is set. Setting RFS signals a DMA service
request if SSCR1[RSRE] is set. After the CPU or DMA reads the FIFO such that it has fewer
entries than the value of SSCR1[RFT], RFS (and the service request or interrupt) is
automatically cleared. SSCR1[RSRE] and SSCR1[RIE] must not both be set.
0 – Receive FIFO level exceeds RFT trigger threshold or the SSP is disabled
1 – Receive FIFO level is at or above RFT trigger threshold, request Interrupt
Table 16-8. SSSR Bit Definitions (Sheet 2 of 3)
0x4140_0008 SSSR Network SSP Serial Port
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
reserved
BC
E
CS
S
TU
R
re
ser
v
ed
TIN
T
re
ser
v
ed
RF
L
TFL RO
R
RF
S
TFS BS
Y
RN
E
TN
F
re
ser
v
ed
Reset ? ? ? ? ? ? ? ? 0 0 0 ? 0 ? ? ? 1 1 1 1 0 0 0 0 0 0 0 0 0 1 ? ?
Bits Name Description