[ECOS] Red-Boot & Multiple Flash IC's

sebastian igielski sebastian.igielski@kolporter.com.pl
Tue Aug 26 19:59:00 GMT 2008


We have porting Red-Boot to our platform based on EP9302 microprocessor 
(produced by Cirrus Logic, ARM920T core inside). I have one question 
about using multiple flash IC's connected to different chip selects, uut 
at first I must tell something about our hardware platform.

In a few words, we have on board following IC's:

1x MCU: EP9302 (ARM920T core, 16 bit wide data bus)
4x SDRAM (one SDRAM chip have 32Mbyte capacity, four banks - [8MBytes 
per bank]) - Total: 128Mbytes of RAM
2x NOR FLASH (JS28F1283D) (connected to two separate chip selects) (The 
NOR flash chips is Intel-Strata FLASH IC's.)

One NOR-FLASH chip have 16-bit data bus. The NOR-Flash chips is placed 
at 0x6000_0000 and 0x7000_0000 in physical memory layout. After 
configuring and enabling the MMU the NOR-Flash chips is mapped as 
follows (virtual address space):

IC #1: 0x6000_0000 - 0x60FF_FFFF
IC #2: 0x6100_0000 - 0x61FF_FFFF

And now is my question about Red-Boot environment. It is possible to 
(and how to do it) use both NOR flash chips?
Now I have working only one chip (placed at virtual address: 

I have no idea how to tell Red-Boot/Strata Flash driver to see my second 
NOR-Flash chip. It is possible to RedBoot handle this kind of hardware 

Some people told me that I must modify the "CYGNUM_FLASH_DEVICES", but 
in my humble opinion this variable defines the FLASH IC's needed to 
coverage the data bus by multiple FLASH IC's (for example: when I have 
32 bit wide data bus, and when I have two 16 bit FLASH IC's to coverage 
32-bit data bus - in that case CYGNUM_FLASH_DEVICES must be set to 2). 
I'm correct?

In our hardware the data bus is 16-bit wide and FLASH IC is 16 bit wide 
(so one flash chip coverage all data bus), the second FLASH IC is used 
to extend size of flash memory size. As i written above, I have working 
first FLASH CHIP. And I don't know to add second chip to RedBoot 

If anybody can suggest me right solution of my problem, or give any 
helpful idea I will be graceful.

I have ecos-2.0 package.

with regards
Sebastian Igielski

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