smbus读取spd方法

来源：互联网发布：成都淘宝运营公司编辑：程序博客网时间：2024/05/21 13:57

smbus设备的bar5一般为smbus设备的io基地址。可以通过设备管理器查看。

Read SPD information

The SMBus DeviceID of memory bank0 is a0, bank1= 0xa2, and bank2 =0xa4

smbus操作的过程如下所示

a. start out Base+0, 1e

b. wait smbus ready

c. output Base+04, (DeviceID+1)

d. out Base+03, offset

e. out Base+02, 48H

f. wait 200ms

g. wait smbus ready

h. input base+05

i. OK

How to wait SMBus ready? Input Base+0, bit0==0 indicates smbus is ready, otherwise(bit0==1), smbus is busy

下面为转载的全文。

思路有了就是不知道怎么实现,请大家帮忙,引用系统软件开发 System Programming中的文章:
怎样读写SMBus上的Device―以获取Intel平台上Memory的SPD信息为例

How to access devices on SMBus--- Take reading SPD information (Intel platform) as example

firing -2005/04/13

0. Essential skills before you start:

l How to read/write PCI configuration space?

l How to read/write I/O space under WindowsNT/2000… platform?

And an Intel south bridge datasheet as reference

1． Basic steps

a. Enable SMBus controller

b. Get SMBus base address

c. Read SPD information, according the device IDs

2． Enable SMBus controller

LPC Interface Bridge Registers (D31:F0), Offset: F2h (FUNC_DIS)，Bit3 :

Software sets this bit to disable the SMBus Host controller function.

0 = SMBus controller is enabled

1 = SMBus controller is disabled

This bit is set to 1(SMBus controller is disabled) by default. So, just set this bit to 0.

(How to make sure you have enabled SMBus controller? Go to ‘Device Manager’ and refresh it, and then check ‘System Device’, where you should find a PCI device named “Intel® 82801DB SMBus Controller” like.)

3． Get SMBus base address

SMBus Controller PCI Register (D31:F3), offset: 20~23H. That’s the SMBus base address. Just read this base address. Normally, the address could be 0x500 or 0x5000

4． Read SPD information

The SMBus DeviceID of memory bank0 is a0, bank1= 0xa2, and bank2 =0xa4

a. start

b. wait smbus ready

c. output Base+04, (DeviceID+1)

d. out Base+03, offset

e. out Base+02, 48H

f. wait 200ms

g. wait smbus ready

h. input base+05

i. OK

Note:

How to wait SMBus ready? Input Base+0, bit0==0 indicates smbus is ready, otherwise(bit0==1), smbus is busy

2005年4月13日 15:38

0 0