AT49LH00B4-33TC ATMEL [ATMEL Corporation], AT49LH00B4-33TC Datasheet - Page 20

• Manufacturer Part Number: AT49LH00B4-33TC
• Description: 4-megabit Top Boot, Bottom Partitioned Firmware Hub and Low-Pin Count Flash Memory
• Manufacturer: ATMEL [ATMEL Corporation]

Multiple Device
Selection
FWH Multiple
Device Selection
20
AT49LH00B4
Table 15. General-purpose Input Register
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.
The strapping values on ID[3:0] must match the values in the IDSEL field when performing
FWH memory cycles. The device will compare the values on the ID[3:0] pins with the IDSEL
field. If there is a mismatch, the device will ignore the remainder of the cycle. The device will
then enter standby mode when the FWH4/LFRAME pin is high and no internal operation is in
progress. The FWH/LAD[3:0] pins will also be placed in a high-impedance state.
Table 16. FWH Multiple Device Selection
0 (Boot Device)
Bit
7:5
4
3
2
1
0
Device
10
11
12
13
14
15
1
2
3
4
5
6
7
8
9
GPI_REG4
GPI_REG3
GPI_REG2
GPI_REG1
GPI_REG0
Reserved
Name
ID3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Description
Reserved for future use.
ID2
0
1
0
1
0
1
0
1
0
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
ID Strapping Pins
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
ID1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
IL
IH
IL
IH
IL
IH
IL
IH
IL
IH
.
.
.
.
.
.
.
.
.
.
ID0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
3379B–FLASH–9/03
IDSEL
0000b
0001b
0010b
0011b
0100b
0101b
0110b
0111b
1000b
1001b
1010b
1011b
1100b
1101b
1110b
1111b