68300

I hope someone can help me.  I am working on a project using the
68332.  It has FLASH ROM at addressed 0x0 - 0x8000 and Internal RAM at
FFE000 or something close to that.  I can easily set these up using
the registers for BOOT ROM and TPU RAM.  The board is suppose to have
external RAM at address 0x100000 - 0x110000 but I can't figure out
what to set up in order to get access to it.  I am currently using
PEMicro BMD cable and Unit32Z libraries.  

I am not sure what type of Flash ROM I have but in general what needs
to be done in order to write to Flash ROM?

Thanks

To access external RAM, you need to set up the chip selects properly.

To do this, you need to know how the hardware of your target is connected 
to the external RAM

You will need to set CSPAR0 and CSPAR1 and the CSBARxx and CSORxx that the 
external RAM is connected to.  It usually takes me the better part of an 
afternoon to get it right.  There are at least 34 bits to set right, and 
the symptom of failure is usually "it doesn't work" with little clue as to why.

The information is in the "MC68332 User's Manual" available at:
http://www.freescale.com/files/microcontrollers/doc/user_guide/MC68332UM.pdf
section 4.8.  There are 34 bits to set properly.  CSBARxx, CSORxx and two 
bits of CSPARx.

The external Flash is also accessed in about the same way.  It is probably 
possible to reprogram the flash if you have the right program in RAM.

Hope this helps.

    Steve Russell
    Nohau

At 02:18 PM 3/2/2005, you wrote:

>I hope someone can help me.  I am working on a project using the
>68332.  It has FLASH ROM at addressed 0x0 - 0x8000 and Internal RAM at
>FFE000 or something close to that.  I can easily set these up using
>the registers for BOOT ROM and TPU RAM.  The board is suppose to have
>external RAM at address 0x100000 - 0x110000 but I can't figure out
>what to set up in order to get access to it.  I am currently using
>PEMicro BMD cable and Unit32Z libraries.
>
>I am not sure what type of Flash ROM I have but in general what needs
>to be done in order to write to Flash ROM?
>
>Thanks


*************************************************************************
Steve Russell                                     mailto:stever@...
Senior Software Design Engineer                      http://www.nohau.com
Nohau                                      phone: (408)866-1820 ext. 1873
                                                        fax: (408)378-7869
NEW mailing address:

275 E. Hacienda Ave.
Campbell, CA 95008
*************************************************************************

palehorse_johnsoga wrote:
> I hope someone can help me.  I am working on a project using the
> 68332.  It has FLASH ROM at addressed 0x0 - 0x8000 and Internal RAM at
> FFE000 or something close to that.  I can easily set these up using
> the registers for BOOT ROM and TPU RAM.  The board is suppose to have
> external RAM at address 0x100000 - 0x110000 but I can't figure out
> what to set up in order to get access to it.  I am currently using
> PEMicro BMD cable and Unit32Z libraries.

The usual method of interfacing to _external_ RAM is to attach address and
data lines to the address and data bus on the '332.  The Chip Enable (CE)
line is then tied to one of the Chip Select pins on the '332.  You may also
need to connect the Write Enable line on the RAM to another Chip Select pin
on the '332 to handle write cycles.  Hopefully you are using 16 bit ram to
match the '332s bus width.

>
> I am not sure what type of Flash ROM I have but in general what needs
> to be done in order to write to Flash ROM?

Writing to an _external_ Flash is usually not toodifficult but varies
somewhat from manufacturer to manufacturer.  To proceed --

1.  Determine the Manufacturer and exact device number of the Flash
installed on your system.

2.  Obtain and _read_ the manufacturer's Data Sheet/Manual for your specific
device.

3.  Write driver routines that generate the correct I/O sequences to unlock
the Flash for writing and to write bytes/blocks of data to the Flash.

>
> Thanks
>
>
>
>
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