SYNCHRONOUS SERIAL INTERFACE (SSI)
MOTOROLA
PORT C
6 - 85
SRD
X:$FFEF
23
16 15
8 7
0
7
0
7
0 7
0
RECEIVE HIGH BYTE
RECEIVE MIDDLE BYTE
RECEIVE LOW BYTE
SERIAL RECEIVE DATA
(RX) REGISTER
(READ ONLY)
SERIAL
RECEIVE
SHIFT
REGISTER
23
16 15
8 7
0
7
0
7
0 7
0
RECEIVE HIGH BYTE
RECEIVE MIDDLE BYTE
RECEIVE LOW BYTE
24 BIT
WL1, WL0
24-BIT DATA
0
0
0
16-BIT DATA
12-BIT DATA
8-BIT DATA
LSB
LSB
LSB
LSB
MSB
MSB
MSB
MSB
LEAST SIGNIFICANT
ZERO FILL
NOTES:
1. Data is received MSB first if SHFD = 0.
2. Compatible with fractional format.
16 BIT
12 BIT
8 BIT
(a) Receive Registers for SHFD = 0
STD
X:$FFEF
23
16 15
8 7
0
7
0
7
0 7
0
TRANSMIT HIGH BYTE
TRANSMIT MIDDLE BYTE
TRANSMIT LOW BYTE
SERIAL TRANSMIT DATA
(TX) REGISTER
(WRITE ONLY)
SERIAL RECEIVE SHIFT REGISTER
SERIAL TRANSMIT
SHIFT REGISTER
23
16 15
8 7
0
7
0
7
0 7
0
TRANSMIT HIGH BYTE
TRANSMIT MIDDLE BYTE
TRANSMIT LOW BYTE
24-BIT DATA
0
0
0
16-BIT DATA
12-BIT DATA
8-BIT DATA
LSB
LSB
LSB
LSB
MSB
MSB
MSB
MSB
LEAST SIGNIFICANT
ZERO FILL
NOTES:
1. Data is sent MSB first if SHFD = 0.
2. Compatible with fractional format.
(b) Transmit Registers for SHFD = 0
Figure 6-45 SSI Programming Model (Sheet 1 of 2)
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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