AMD Geode SC1201 - Manual (Page 167)

AMD Geode™ SC1200/SC1201 Processor Data Book 167
Core Logic Module 32579B
6.2.11 GPIO Interface
Up to 64 GPIOs in the in the Core Logic module are pro-
vided for system control. For further information, see Sec-
tion 4.2 "Pin Multiplexing, Interrupt Selection, and Base
Address Registers" on page 72 and Table 6-30 "F0BAR0+I/
O Offset: GPIO Configuration Registers" on page 224.
Note: Not all GPIOs are available on SC1200/SC1201
processor balls. GPIOs [63:42], [31:21], and [5:2]
are reserved.
6.2.12 Integrated Audio
The Core Logic module provides hardware support for the
Virtual (soft) Audio subsystem as part of the Virtual System
Architecture™ (VSA) technology for capture and playback
of audio using an external codec. This eliminates much of
the hardware traditionally associated with audio functions.
This hardware support includes:
• Six-channel buffered PCI bus mastering interface.
• AC97 version 2.0 compatible interface to the codec. Any
codec, which supports an independent input and output
sample rate conversion interface, can be used with the
Core Logic module.
Additional hardware provides the necessary functionality
for VSA. This hardware includes the ability to:
• Generate an SMI to alert software to update required
data. An SMI is generated when either audio buffer is
half empty or full. If the buffers become completely
empty or full, the Empty bit is asserted.
• Generate an SMI on I/O traps.
• Trap accesses for sound card compatibility at either I/O
Port 220h-22Fh, 240h-24Fh, 260h-26Fh, or 280h-28Fh.
• Trap accesses for FM compatibility at I/O Port 388h-
38Bh.
• Trap accesses for MIDI UART interface at I/O Port 300h-
301h or 330h-331h.
• Trap accesses for serial input and output at COM2 (I/O
Port 2F8h-2FFh) or COM4 (I/O Port 2E8h-2EFh).
• Support trapping for low (I/O Port 00h-0Fh) and/or high
(I/O Port C0h-DFh) DMA accesses.
• Support hardware status register reads in Core Logic
module, minimizing SMI overhead.
• Support is provided for software-generated IRQs on IRQ
2, 3, 5, 7, 10, 11, 12, 13, 14, and 15.
The following subsections include details of the registers
used for configuring the audio interface. The registers are
accessed through F3 Index 10h, the Base Address Regis-
ter (F3BAR0) in Function 3. F3BAR0 sets the base
address for the audio support registers as shown in Table
6-37 "F3: PCI Header Registers for Audio Configuration"
on page 262.
6.2.12.1 Data Transport Hardware
The data transport hardware can be broadly divided into
two sections: bus mastering and the codec interface.
Audio Bus Masters
The Core Logic module audio hardware includes six PCI
bus masters (three for input and three for output) for trans-
ferring digitized audio between memory and the external
codec. With these bus master engines, the Core Logic
module off-loads the CPU and improves system perfor-
mance.
The programming interface defines a simple scatter/gather
mechanism allowing large transfer blocks to be scattered to
or gathered from memory. This cuts down on the number of
interrupts to and interactions with the CPU.
The six bus masters that directly drive specific slots on the
AC97 interface are described in Table 6-10.
Table 6-10. Bus Masters That Drive Specific Slots of the AC97 Interface
Audio Bus
Master # Slots Description
0 3 and 4 32-Bit output to codec. Left and right channels.
1 3 and 4 32-Bit input from codec. Left and right channels.
2 5 16-Bit output to codec.
3 5 16-Bit input from codec.
4 6 or 11 16-Bit output to codec. Slot in use is determined by F3BAR0+Memory Offset 08h[19].
5 6 or 11 16-Bit input from codec. Slot in use is determined by F3BAR0+Memory Offset 08h[20].