
Synchronous Serial Interface (SSI)
24-42
Freescale Semiconductor
•
Rx frame sync initiated one bit before data is received (SSI_RCR[REFS] = 1)
•
Tx shifting w.r.t. bit 0 of TXSR (SSI_TCR[TXBIT0] = 1)
•
Rx shifting w.r.t. bit 0 of RXSR (SSI_RCR[RXBIT0] = 1)
•
Tx FIFO is enabled (SSI_TCR[TFEN0] = 1)
•
Rx FIFO is enabled (SSI_RCR[RFEN0] = 1)
•
Internally-generated frame sync (SSI_TCR[TFDIR] = 1)
•
Externally-generated bit clock (SSI_TCR[TXDIR] = 0)
Any alteration of these bits does not affect the operational conditions of the SSI unless AC97 mode is
deselected. Hence, the only control bits that need to be set to configure the data transmission/reception are
the SSI_CCR[WL, DC] bits. In AC97 mode, the WL bits can only legally take the values corresponding
to 16-bit (truncated data) or 20-bit time slots. If the WL bits are set to select 16-bit time slots, while
receiving, the SSI pads the data (four least significant bits) with 0s, and while receiving, the SSI stores only
the 16 most significant bits in the Rx FIFO.
The following sequence should be followed for programming the SSI to work in AC97 mode:
1. Program the SSI_CCR[WL] bits to a value corresponding to 16 or 20 bits. The WL bit setting is
only for the data portion of the AC97 frame (slots #3 through #12). The tag slot (slot #0) is always
16-bits wide and the command address and command data slots (slots #1 and #2) are always 20 bits
wide.
2. Select the number of time slots through the SSI_CCR[DC] bits. For AC97 operation, the DC bits
should be set to a value of 0xC, resulting in 13 time slots per frame.
3. Write data to be transmitted in Tx FIFO 0 (through Tx data register 0)
4. Program the SSI_ACR[FV, TIF, RD, WR and FRDIV] bits
5. Update the contents of SSI_ACADD, SSI_ACDAT and SSI_ATAG (for fixed mode only) registers
6. Enable AC97 mode (SSI_ACR[AC97EN] bit)
After the SSI starts transmitting and receiving data after being configured in AC97 mode, the processor
needs to service the interrupts when they are raised (updates to command address/data or tag registers,
reading of received data, and writing more data for transmission). Further details regarding fixed and
variable mode implementation appear in the following sections.
While using AC97 in two-channel mode (TCH = 1), it is recommended that the received tag is not stored
in the Rx FIFO (TIF = 0). If you need to update the SSI_ATAG register and also issue a RD/WR command
(in a single frame), it is recommended that the SSI_ATAG register is updated prior to issuing a RD/WR
command.
24.4.1.5.1
AC97 Fixed Mode (SSI_ACR[FV]=0)
In fixed mode of operation, SSI transmits in accordance with the frame rate divider bits that decide the
number of frames for which the SSI should be idle, after operating for one frame. The following shows the
slot assignments in a valid transmit frame:
•
Slot 0: The tag value (written by the user program)
•
Slot 1: If RD/WR command, command address
MCF5329 Reference Manual, Rev 3
Содержание MCF5329
Страница 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 126: ...Enhanced Multiply Accumulate Unit EMAC 4 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 564: ...Liquid Crystal Display Controller LCDC 22 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 692: ...Programmable Interrupt Timers PIT0 PIT3 28 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 720: ...Queued Serial Peripheral Interface QSPI 30 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 790: ...Message Digest Hardware Accelerator MDHA 33 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 902: ...Register Memory Map Quick Reference A 26 Freescale Semiconductor MCF5329 Reference Manual Rev 3...