Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Hoja De Datos

 1008

SAM9M10 [DATASHEET]

6355F–ATARM–12-Mar-13

The tag slot, or slot 0, is a 16-bit wide slot that always goes at the beginning of an outgoing or incoming frame.
Within tag slot, the first bit is a global bit that flags the entire frame validity. The next 12 bit positions sampled by the
AC97 Controller indicate which of the corresponding 12 time slots contain valid data. The slot’s last two bits (com-
bined) called Codec ID, are used to distinguish primary and secondary codec.

The 16-bit wide tag slot of the output frame is automatically generated by the AC97 Controller according to the
transmit request of each channel and to the SLOTREQ from the previous input frame, sent by the AC97 Codec, in
Variable Sample Rate mode.

The command/status slot is a 20-bit wide slot used to control features, and monitors status for AC97 Codec
functions.

The control interface architecture supports up to sixty-four 16-bit wide read-write registers. Only the even registers
are currently defined and addressed.

Slot 1’s bitmap is the following:

• Bit 19 is for read-write command, 1= read, 0 = write.

• Bits [18:12] are for control register index.

• Bits [11:0] are reserved.

Slot 2 is a 20-bit wide slot used to carry 16-bit wide AC97 Codec control register data. If the current command port
operation is a read, the entire slot time is stuffed with zeros. Its bitmap is the following:

• Bits [19:4] are the control register data

• Bits [3:0] are reserved and stuffed with zeros.

Slots [3:12] are 20-bit wide data slots, they usually carry audio PCM and/or modem I/O data.