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C5402 bootloader

Started by Jean Viljoen March 28, 2003
Dear Group

I have a STMicro M29W010B 8-bit wide Flash memory module connected to a
C5402 on a custom board. The bootloader must load the program in flash
to onboard memory and start executing the program.

The start of the stored program is at address 0x4000. According to
SPRA618A.pdf, the bootloader reads the start address of the boot table
from address 0xFFFF in data space. How do I specify the 16-bit start
address (0x4000) in a 8-bit device, like the flash memory? (Because it
is only after the bootloader finds a valid keyword that it determines
weather the Flash is 8 or 16 bits wide)

Rgds Jean Viljoen
Design Engineer
Azoteq (Pty) Ltd

Tel +27 21 863 0033
Fax +27 21 863 1512




In my understanding, what C5402 bootloader is looking for at the
first time is the address of the "boot table". An 8-bit boot table
must starts with 0x08 followed by 0xAA. The exact format of boot
table can be found in the section "Parallel Boot Mode" of SPRA618.

To specify the address of this boot table using 8-bit wide flash, you
must:
- put your flash in DATA space
- put LSB of boot table address in 0xFFFF
- put MSB of boot table address in 0xFFFE
- you must program yor 8-bit wide flash in big-endian format (MSB
first).

For example, if your boot table is located at 0x4000:
0xFFFF(DATA) contains 0x00
0xFFFE(DATA) contains 0x40

I suppose that what you store at address 0x4000 is the "BOOT TABLE"

Hope it helps. --- In , "Jean Viljoen" <jean.viljoen@a...> wrote:
> Dear Group
>
> I have a STMicro M29W010B 8-bit wide Flash memory module connected
to a
> C5402 on a custom board. The bootloader must load the program in
flash
> to onboard memory and start executing the program.
>
> The start of the stored program is at address 0x4000. According to
> SPRA618A.pdf, the bootloader reads the start address of the boot
table
> from address 0xFFFF in data space. How do I specify the 16-bit
start
> address (0x4000) in a 8-bit device, like the flash memory?
(Because it
> is only after the bootloader finds a valid keyword that it
determines
> weather the Flash is 8 or 16 bits wide)
>
> Rgds > Jean Viljoen
> Design Engineer
> Azoteq (Pty) Ltd
>
> Tel +27 21 863 0033
> Fax +27 21 863 1512