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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262-004US
869
Synchronous Serial Port—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
20.5.3
SSP Status Register
The SSP status register (SSSR) contains bits that signal overrun errors as well as the
transmit and receive FIFO service requests. Each of these hardware-detected events
signal an interrupt request to the interrupt controller. The status register also contains
flags that indicate when the SSP is actively transmitting characters, when the transmit
FIFO is not full, and when the receive FIFO is not empty (no interrupt generated).
Register Name:
SSCR1
Block
Base Address:
0xC801_20
Offset Address
0x04
Reset Value
0x0000_0000
Register Description:
SSC Control Register 1
Access:
(See below.)
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
STRF
EF
W
R
RF
T
TF
T
MWDS
SP
H
SP
O
LBM
TIE
RIE
Register
SSCR1
Bits
Name
Description
Reset value
Access
31:16
(Reserved)
(Reserved)
0x0000
RV
15
STRF
Select FIFO for EFWR:
0 = Transmit FIFO is selected for “enable FIFO write/read”
1 = Receive FIFO is selected for “enable FIFO write/read”
0x0000
RW
14
EFWR
Enable FIFO Write/Read:
0 = FIFO write/read loopback function is disabled; normal operation
enabled
1 = FIFO write/read loopback function is enabled
0x0000
RW
13:10
RFT
Receive FIFO Threshold.
Sets threshold level at which Receive FIFO asserts interrupt. This level
should be set to the threshold value minus 1.
0x0000
RW
9:6
TFT
Transmit FIFO Threshold.
Sets threshold level at which Transmit FIFO asserts interrupt. This level
should be set to the threshold value minus 1.
0x0000
RW
5
MWDS
National Microwire* Data Size
0 = 8 bit Microwire format
1 = 16 bits Microwire format
0x0000
RW
4
SPH
Motorola* SPI SSP_SCLK phase setting:
0 = SSP_SCLK is inactive one full cycle at the start of a frame and 1/2
cycle at the end of a frame.
1 = SSP_SCLK is inactive 1/2 cycle at the start of a frame and one full
cycle at the end of a frame.
0x0000
RW
3
SPO
Motorola SPI SSP_SCLK polarity setting:
0 = The inactive or idle state of SSP_SCLK is low.
1 = The inactive or idle state of SSP_SCLK is high.
0x0000
RW
2
LBM
Loop Bank Mode Enable bit.
0 = Normal serial port operation enabled
1 = Output of transmit serial shifter connected to input of receive serial
shifter, internally
0x0000
RW
1
TIE
Transmit FIFO Interrupt Enable
0 = Transmit FIFO level interrupt is disabled
1 = Transmit FIFO level interrupt is enabled
0x0000
RW
0
RIE
Receive FIFO Interrupt Enable
0 = Receive FIFO level interrupt is disabled
1 = Receive FIFO level interrupt is enabled
0x0000
RW