Cirrus Logic EP93xx - Manual (Page 693)

DS785UM1 22-5
Copyright 2007 Cirrus Logic
AC’97 Controller
EP93xx User’s Guide
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22.2.2.4 GPIOTXCOMPLETE
The transmit GPIOTXCOMPLETE interrupt is asserted when all values written to the
AC97S12Data have been transmitted. It is cleared when any data is written to the
AC97S12Data.
22.2.2.5 SLOT2INT
The receive SLOT2INT interrupt is asserted when the AC97S2Data register has new data
that has not been read. By reading the data in the AC97S2Data register the SLOT2INT
interrupt is cleared.
22.2.2.6 SLOT1TXCOMPLETE
The transmit SLOT1TXCOMPLETE interrupt is asserted when all values written to the
AC97S1Data have been transmitted. It is cleared when any data is written to the
AC97S1Data.
22.2.2.7 SLOT2TXCOMPLETE
The transmit SLOT2TXCOMPLETE interrupt is asserted when all values written to the
AC97S2Data have been transmitted. It is cleared when any data is written to the
AC97S2Data.
22.3 System Loopback Testing
A loopback test mode is available for system testing so that data transmitted on SDATAOUT
can also be received on SDATAIN. Loopback mode is entered when a “1” is written to the
LOOP bit in AC97GCR register. For normal operation the LOOP bit must always be “0”,
which is also the default state at reset.
Note: For this test mode to work, an external bit clock will need to be supplied.
22.4 Registers
Table 22-2. AC’97 Register Memory Map
Address Type Name Description
0x8088_0000 Read/Write AC97DR1 Data read or written from/to FIFO1
0x8088_0004 Read/Write AC97RXCR1 Control register for receive
0x8088_0008 Read/Write AC97TXCR1 Control register for transmit
0x8088_000C Read AC97SR1 Status register
0x8088_0010 Read AC97RISR1 Raw interrupt status register
0x8088_0014 Read AC97ISR1 Interrupt Status
0x8088_0018 Read/Write AC97IE1 Interrupt Enable
0x8088_001C - - Reserved
0x8088_0020 Read/Write AC97DR2 Data read or written from/to FIFO2
0x8088_0024 Read/Write AC97RXCR2 Control register for receive
0x8088_0028 Read/Write AC97TXCR2 Control register for transmit
0x8088_002C Read AC97SR2 Status register