User`s guide

C.13.1 Flash Memory Segment Select Register

Table C–10 lists the register address for the ﬂash ROM. The ﬂash ROM is

partitioned into two 512KB segments. Write a value of 0 to ISA address 800

to select the lower 512KB. Write a value of 1 to ISA address 800 to select the

higher 512KB. This register is write-only.

Table C–10 Flash Memory Segment Select Register

Offset Physical Address Register

800 1 C001 0000 Flash segment select

C.13.2 Flash Memory Addresses

Table C–11 lists the address range for the ﬂash ROM.

Table C–11 Flash Memory Addresses (Within Segment)

Offset Physical Address Capacity

0 0000—7 FFFF 3 FFF8 0000—3 FFFF FFFF 512KB

C.13.3 Flash ROM Conﬁguration Registers

Table C–12 lists the conﬁguration registers for the Intel 28F008SA 1MB ﬂash

ROM. A read transaction is simple and is performed by reading from the

appropriate address; however, to write data, the ﬂash ROM must ﬁrst be

erased. The structure of the ﬂash ROM allows only the ﬂash ROM to be erased

in 64KB blocks. See Section C.13.4.

In order to change 1 byte, the following steps must be completed:

1. Read the whole 64KB block into memory.

2. Change the desired byte in memory.

3. Erase the 64KB block in ﬂash ROM.

4. Write the whole 64KB block from memory to the ﬂash ROM.

C–14 PCI Address Maps