linux-mips
[Top] [All Lists]

Re: MTD drivers and byte/word mode

To: "Stephen Mose Aaskov" <sma@2m.dk>
Subject: Re: MTD drivers and byte/word mode
From: "Jon Burgess" <Jon_Burgess@eur.3com.com>
Date: Tue, 3 Sep 2002 09:28:29 +0100
Cc: linux-mips@linux-mips.org
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org

> It looks as if the adresses calculated by
> cfi_build_cmd_addr() is the double of what my FLASH
> chips are using.
> eg. the CFI query is written to 0xaa where my chip
> in word mode expects the query command to be written
> to 0x55

We have just such a setup working in our product with a 16 bit AMD flash using
the CFI diver.

The 0xAA address as far as the programmer is concerned looks wrong, but the
flash chip is expecting addresses of 16bit data which are shifted 1 address line
from the address of 8 bit data. On our board the generic 8/16 bit bus address
lines are connected to the 16 bit flash as:
     Bus A0 -> Unused
     Bus A1 -> Flash A0,
     Bus A2 -> Flash A1
     etc,

When the CPU accesses addres 0xAA the flash will see 0x55.

     Jon



<Prev in Thread] Current Thread [Next in Thread>