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Synchronous Serial Interface (SSI)
27-32
Freescale Semiconductor
27.3.14 SSI AC97 Control Register (SSI_ACR)
SSI_ACR controls various features of the SSI operating in AC97 mode.
Address: 0xFC0B_C038 (SSI_ACR)
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 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
FRDIV
WR RD TIF FV AC97EN
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 27-21. SSI AC97 Control Register (SSI_ACR)
Table 27-19. SSI_ACR Field Descriptions
Field
Description
31–11
Reserved, must be cleared.
10–5
FRDIV
Frame rate divider. Controls the frequency of AC97 data transmission/reception. This field is programmed with the
number of frames for which the SSI should be idle after operating in one frame. Through these bits, the AC97
frequency of operation, from 48 KHz (000000) to 1 KHz (101111) can be achieved.
E.g: 001010 (10 Decimal) equals SSI operates once every 11 frames.
4
WR
Write command. Specifies whether the next frame carries an AC97 write command or not. When this bit is set, the
corresponding tag bits (corresponding to command address and command data slots of the next transmit frame) are
automatically set. The SSI automatically clears this bit after completing transmission of a frame.
0 Next frame does not have a write command
1 Next frame does have a write command
Note:
Do not set WR and RD at the same time.
3
RD
Read command. Specifies whether the next frame carries an AC97 read command or not. When this bit is set, the
corresponding tag bit (corresponding to command address slot of the next transmit frame) is automatically set. The
SSI automatically clears this bit after completing transmission of a frame.
0 Next frame does not have a read command
1 Next frame does have a read command
Note:
Do not set WR and RD at the same time.
2
TIF
Tag in FIFO. Controls the destination of the information received in the AC97 tag slot (slot #0).
0 Tag information stored in SSI_ATAG register
1 Tag information stored in Rx FIFO 0
1
FV
Fixed/variable operation.
0 AC97 fixed mode
1 AC97 variable mode
0
AC97EN
AC97 mode enable. Refer to
Section 27.4.1.5, “AC97 Mode,”
for details of AC97 operation.
0 AC97 mode disabled
1 AC97 mode enabled
Summary of Contents for MCF54455
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Page 67: ...Freescale Semiconductor 1 ...
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Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
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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 ...
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