W83L518D_05 Datasheet, PDF (12/25 Pages) Winbond – Integrated Media Reader

W83L518D
07h logical device select
30h _{logical device control}
3Fh
40h
logical device
configuration
FEh
global registers
One set per
logical device
6.2 Compatible PnP
6.2.1 Extended Function Register
W83L518D/W83L519D provide two methods to enter Extended Function mode (compatible PnP) and
access configuration registers dependent on value of HEFRAS (bit 6 of CR26. The corresponding
power-on setting pin is pin 14) as follows:
HEFRAS
0
1
ADDRESS AND VALUE
write 83h to I/O address 2Eh twice
write 83h to I/O address 4Eh twice
In Compatible PnP, a specific value (83h) must be written twice to the Extended Function Enable
Register (EFER at I/O address 2Eh or 4Eh). Secondly, an index value (02h, 07h-FFh) must be written
to the Extended Function Index Register (EFIR, I/O address at 2Eh or 4Eh which is the same as
EFER) to identify which configuration register is to be accessed. User can then access the addressed
configuration register through the Extended Function Data Register (EFDR, I/O address at 2Fh or
4Fh).
After programming of the configuration register is completed, another specific value (0AAh) should be
written to EFER to leave Extended Function mode to prevent inadvertent accesses to those
configuration registers. User may write a "1" to bit 5 of CR26 (LOCKREG) to prevent configuration
registers from accidental accesses.
6.2.2 Extended Functions Enable Register (EFER)
After a power-on reset, W83L518D/W83L519D enters the default operation mode. A specific value
must be programmed into the Extended Function Enable Register (EFER) so that configuration
registers can be accessed. On a PC/AT system, its I/O address is 2Eh or 4Eh (as described in
previous section).
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