AMD SB600 Specifications download pdf (Page 66)

2008 Advanced Micro Devices Inc.

Sample Programs

AMD SB600 BIOS Developer’s Guide (Public Version) Proprietary

Page 66

Sample Program

The sample program below sets the primary slave to UDMA mode 5:

push eax

push dx

; For primary slave, set register 56h, bits [6:4] to 5 for UDMA mode 5

mov dx,0CF8h ; To access PCI configuration space of IDE controller

mov eax,8000A154h ; Device 14h, function 1, register space 54h – 57h

out dx,eax ;

mov dx,0CFEh ; To access register 56h

in al,dx ; Current value of register 56h

and al,8Fh ; Clear bits 6:4.

or al,50h ; Set UDMA 5 mode for primary slave.

out dx,al

; Enable primary slave UDMA mode in register 54h, bit 1,

mov dx,CFCh ; To access register 54h

in al,dx ; Current value of register 54h

or al,02h ; Set bit 1

out dx,al

pop dx

pop eax

ret

14.3.4 IDE Channel Disable

To disable an IDE channel, the BIOS must:

1. Set IDE channel programmable logic enable bit in Reg09h.

2. Set IDE channel disable bit in Reg48h to disable IDE channel.

Note: No IDE I/O port access is allowed between step (1) and step (2). It is recommended that the

BIOS execute step (2) immediately after step (1). There should be no ‘in’ instruction between two

‘out’ instructions to register 09h and 48h.

After the IDE disable sequence, the IDE channel programmable logic enable bit will be cleared

automatically.

Sample program: Disable secondary channel

; Read current register 48h-49h on IDE controller

push eax

push bx

1 2 ... 61 62 63 64 65 66 67 68 69 70 71 ... 97 98

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AMD SB600 Specifications Page 66