![Freescale Semiconductor MCF54455 Reference Manual Download Page 678](http://html1.mh-extra.com/html/freescale-semiconductor/mcf54455/mcf54455_reference-manual_2330541678.webp)
Synchronous Serial Interface (SSI)
Freescale Semiconductor
27-11
27.3.5
SSI Receive FIFO 0 and 1 Registers
The SSI receive FIFO registers are 15x32-bit registers and are not directly accessible. They always accept
data from the receive shift register (RXSR). If the associated interrupt is enabled, an interrupt is generated
when the data level in either of the SSI receive FIFOs reaches the selected threshold.
27.3.6
SSI Receive Shift Register (RXSR)
RXSR is a 24-bit shift register receiving incoming data from the SSI_RXD pin. This register is not directly
accessible. When a continuous clock is used, data is shifted in by the bit clock when the associated frame
sync is asserted. When a gated clock is used, data is shifted in by the gated clock. Data is assumed to be
received msb first if SSI_RCR[SHFD] is cleared. If this bit is set, the data is received lsb first. Data is
transferred to the appropriate SSI receive data register or receive FIFOs (if the receive FIFO is enabled and
the corresponding SSI_RX is full) after a word has been shifted in. For receiving less than 24 bits of data,
the lsb bits are appended with 0.
The following figures show the receiver loading and shifting operation. They illustrate some possible
values for WL, which can be extended for the other values.
Address: 0xFC0B_C008 (SSI_RX0)
0xFC0B_C00C (SSI_RX1)
Access: User read/write
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
R
SSI_RX
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Figure 27-9. SSI Receive Data Registers (SSI_RX0, SSI_RX1)
Table 27-6. SSI_RX0/1 Field Descriptions
Field
Description
31–0
SSI_RX
SSI receive data. SSI_RX0/1 are implemented as the first word of their respective Rx FIFOs. These bits receive data
from RXSR depending on the mode of operation. If both FIFOs are in use, data is transferred to each data register
alternately. SSI_RX1 is only used in two-channel mode.
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...