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AMD Geode™ SC2200 Processor Data Book 281
Core Logic Module - Audio Registers - Function 3
32580B
1 Assert Masked Internal IRQ1.
0: Disable.
1: Enable.
0 Reserved. Must be set to 0.
Offset 20h Audio Bus Master 0 Command Register (R/W) Reset Value: 00h
Audio Bus Master 0: Output to codec; 32-bit; Left and Right Channels; Slots 3 and 4.
7:4 Reserved. Must be set to 0. Must return 0 on reads.
3 Read or Write Control. Sets the transfer direction of the Audio Bus Master.
0: PCI reads are performed.
1: PCI writes are performed.
This bit must be set to 0 (read), and should not be changed when the bus master is active.
2:1 Reserved. Must be set to 0. Must return 0 on reads.
0 Bus Master Control. Controls the state of the Audio Bus Master.
0: Disable.
1: Enable.
Setting this bit to 1 enables the bus master to begin data transfers.
When writing 0 to this bit, the bus master must either be paused, or reach EOT. Writing 0 to this bit while the bus master is
operating may result in unpredictable behavior (and may crash the bus master state machine). The only recovery from such
unpredictable behavior is a PCI reset.
Offset 21h Audio Bus Master 0 SMI Status Register (RC) Reset Value: 00h
Audio Bus Master 0: Output to codec; 32-bit; Left and Right Channels; Slots 3 and 4.
7:2 Reserved.
1 Bus Master Error. Indicates if hardware encountered a second EOP before software has cleared the first.
0: No.
1: Yes.
If hardware encounters a second EOP (end of page) before software has cleared the first, it causes the bus master to pause
until this register is read to clear the error.
0 End of Page. Indicates if the bus master transferred data which is marked by EOP bit in the PRD table (bit 30).
0: No.
1: Yes.
Offset 22h-23h Not Used
Offset 24h-27h Audio Bus Master 0 PRD Table Address (R/W) Reset Value: 00000000h
Audio Bus Master 0: Output to codec; 32-bit; Left and Right Channels; Slots 3 and 4.
31:2 Pointer to the Physical Region Descriptor Table. This bit field contains a PRD table pointer for Audio Bus Master 0.
When written, this register points to the first entry in a PRD table. Once Audio Bus Master 0 is enabled (Command Register
bit 0 = 1), it loads the pointer and updates this register (by adding 08h) so that it points to the next PRD.
When read, this register points to the next PRD.
1:0 Reserved. Must be set to 0.
Note: The Physical Region Descriptor (PRD) table consists of one or more entries - each describing a memory region to or from
which data is to be transferred. Each entry consists of two DWORDs.
DWORD 0: [31:0] = Memory Region Physical Base Address
DWORD 1: 31 = End of Table Flag
30 = End of Page Flag
29 = Loop Flag (JMP)
[28:16] = Reserved (0)
[15:0] = Byte Count of the Region (Size)
Table 6-38. F3BAR0+Memory Offset: Audio Configuration Registers (Continued)
Bit Description