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Synchronous Serial Interface (SSI)
Freescale Semiconductor
27-35
27.3.19 SSI Receive Time Slot Mask Register (SSI_RMASK)
This register controls the time slots that the SSI receives data in network mode.
27.4
Functional Description
27.4.1
Detailed Operating Mode Descriptions
The following sections describe in detail the main operating modes of the SSI module: normal, network,
gated clock, I
2
S, and AC97.
27.4.1.1
Normal Mode
Normal mode is the simplest mode of the SSI. It transfers data in one time slot per frame. A time slot is a
unit of data and the WL bits define the number of bits in a time slot. In continuous clock mode, a frame
sync occurs at the beginning of each frame. The following factors determine the length of the frame:
•
Period of the serial bit clock (DIV2, PSR, PM bits for internal clock or the frequency of the external
clock on the SSI_BCLK port)
•
Number of bits per time slot (WL bits)
•
Number of time slots per frame (DC bits)
If normal mode is configured with more than one time slot per frame, data transfers only in the first time
slot of the frame. No data transfers in subsequent time slots. In normal mode, DC values corresponding to
more than a single time slot in a frame only result in lengthening the frame.
27.4.1.1.1
Normal Mode Transmit
Conditions for data transmission from the SSI in normal mode are:
1. SSI enabled (SSI_CR[SSI_EN] = 1)
2. Enable FIFO and configure transmit and receive watermark if the FIFO is used.
Address: 0xFC0B_C04C (SSI_RMASK)
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
RMASK
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 27-26. SSI Receive Time Slot Mask Register (SSI_RMASK)
Table 27-24. SSI_RMASK Field Descriptions
Field
Description
31–0
RMASK
Receive mask. Indicates which received time slot has been masked in the current frame. Each bit corresponds
to the respective time slot in the frame. If a change is made to the register contents, the reception pattern is
updated from the next time slot. Receive mask bits should not be used in I
2
S slave mode.
0 Valid time slot
1 Time slot masked (no data received in this time slot)
Summary of Contents for MCF54455
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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 ...
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