at49lh004 ATMEL Corporation, at49lh004 Datasheet - Page 22

• Manufacturer Part Number: at49lh004
• Description: 4-megabit Firmware Hub And Low-pin Count Flash Memory
• Manufacturer: ATMEL Corporation

12. General Purpose Input Register
13. Multiple Device Selection
22
AT49LH004
A General-purpose Input Register is provided to read the status of the GPI[4:0] pins when
using the FWH/LPC interface. Since this is a pass-through register, there is no default value. It
is recommended that the GPI[4:0] pins be in their desired state before FWH4/LFRAME is
brought low for the beginning of the next bus cycle and remain in that state until the end of the
cycle.
Table 12-1.
Table 12-2.
Multiple devices may be used in a system to increase the overall memory density. By using
the four ID strapping pins, ID[3:0], up to 16 devices may be attached to the same bus. BIOS
support, bus loading, or the attaching bridge may limit the actual number of devices that can
be connected to the bus.
The boot device must have ID[3:0] equal to 0000b, and all subsequent devices should use
sequential up-count strapping.
Register Name
Bit
7:5
GPI_REG
4
3
2
1
0
GPI Register Memory Address
General-purpose Input Register
GPI_REG4
GPI_REG3
GPI_REG2
GPI_REG1
GPI_REG0
Reserved
Associated Pins
Name
GPI[4:0]
Description
Reserved for future use.
0
1
0
1
0
1
0
1
0
1
FFBC0100H
FWH Mode
Register Memory Address
GPI4 input pin is at V
GPI4 input pin is at V
GPI3 input pin is at V
GPI3 input pin is at V
GPI2 input pin is at V
GPI2 input pin is at V
GPI1 input pin is at V
GPI1 input pin is at V
GPI0 input pin is at V
GPI0 input pin is at V
FF7C0100H
LPC Mode
IL
IH
IL
IH
IL
IH
IL
IH
IL
IH
.
.
.
.
.
.
.
.
.
.
Register Type
3383D–FLASH–6/05
Read Only