W83697HF/F
10.3 Configuration Sequence
To program W83697HF configuration registers, the following configuration sequence must be followed:
(1). Enter the extended function mode
(2). Configure the configuration registers
(3). Exit the extended function mode
10.3.1 Enter the extended function mode
To place the chip into the extended function mode, two successive wrtites of 0x87 must be applied to
Extended Function Enable Registers(EFERs, i.e. 2Eh or 4Eh).
10.3.2 Configurate the configuration registers
The chip selects the logical device and activates the desired logical devices through Extended Function
Index Register(EFIR) and Extended Function Data Register(EFDR). EFIR is located at the same address
as EFER, and EFDR is located at address (EFIR+1).
First, write the Logical Device Number (i.e.,0x07) to the EFIR and then write the number of the desired
logical device to the EFDR. If accessing the Chip(Global) Control Registers, this step is not required.
Secondly, write the address of the desired configuration register within the logical device to the EFIR and
then write (or read) the desired configuration register through EFDR.
10.3.3 Exit the extended function mode
To exit the extended function mode, one write of 0xAA to EFER is required. Once the chip exits the
extended function mode, it is in the normal running mode and is ready to enter the configuration mode.
10.3.4 Software programming example
The following example is written in Intel 8086 assembly language. It assumes that the EFER is located
at 2Eh, so EFIR is located at 2Eh and EFDR is located at 2Fh. If HEFRAS (CR26 bit 6) is set, 4Eh can
be directly replaced by 4Eh and 2Fh replaced by 4Fh.
Publication Release Date: Feb. 2002
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Revision 0.70
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