w83627hg Winbond Electronics Corp America, w83627hg Datasheet - Page 83

• Manufacturer Part Number: w83627hg
• Description: Winbond Lpc I/o
• Manufacturer: Winbond Electronics Corp America

tion registers. The designer can also set bit 5 of CR26°LOCKREG±to high to protect the configura-
tion registers against accidental accesses.
The configuration registers can be reset to their default or hardware settings only by a cold reset °pin
MR = 1±. A warm reset will not affect the configuration registers.
9.1.1.2
After a power-on reset, the W83627HF/F enters the default operating mode. Before the W83627HF
/Fenters the extended function mode, a specific value must be programmed into the Extended Func-
tion Enable Register°EFER±so that the extended function register can be accessed. The Extended
Function Enable Registers are write-only registers. On a PC/AT system, their port addresses are 2Eh
or 4Eh °as described in previous section±.
9.1.1.3
°EFDRs±
After the extended function mode is entered, the Extended Function Index Register°EFIR±must be
loaded with an index value °02h, 07h-FEh± to access Configuration Register 0°CR0±, Configura-
tion Register 7°CR07±to Configuration Register FE°CRFE±, and so forth through the Extended
Function Data Register°EFDR±. The EFIRs are write-only registers with port address 2Eh or 4Eh
°as described in section 12.2.1±on PC/AT systems; the EFDRs are read/write registers with port
address 2Fh or 4Fh °as described in section 9.2.1± on PC/AT systems.
9.1.2
To program W83627HF/F configuration registers, the following configuration sequence must be
followedš
°1± Enter the extended function mode
°2± Configure the configuration registers
°3± Exit the extended function mode
9.1.2.1
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±.
9.1.2.2
The chip selects the logical device and activates the desired logical devices through Extended Func-
tion 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 de-
sired 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.
Configuration Sequence
Extended Functions Enable Registers °EFERs±
Enter the extended function mode
Configurate the configuration registers
Extended Function Index Registers °EFIRs±, Extended Function Data Registers
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W83627HF/ F/ HG/ G
Publication Release Date: June 09, 2006
Revision 2.27