[N8VEM: 18162] FLASH4 in-system flash memory reprogramming tool

William R Sowerbutts

2014-06-08 11:20:58 UTC

Hi everyone

Wayne has very kindly run some tests and confirmed that FLASH4 works with;

* Mark IV SBC
* SBCv2
* N8-2312

He has also confirmed that the 29F040 flash chips work in addition to the
39F040 chips I have been testing with.

I wanted to clarify that FLASH4 works with binary ROM images and does not
support reading Intel Hex format files. Hex files can be easily converted to
binaries using "hex2bin" or the "srec_cat" program from SRecord.

I also wanted to warn that forcing Z180 DMA access mode on the N8-2312 will
not work and will corrupt a few bytes in RAM. Bank switching through RomWBW,
which is the default mode when RomWBW is detected, should work correctly. The
documentation has been updated to reflect this:
http://sowerbutts.com/8bit/flash4-v1.0.2b.zip

I would welcome further feedback from anyone using this. I am particularly
interested to hear if anyone has tested this with 29C series flash memories
as these use an entirely different programming strategy.

Thanks

Will

Post by William R Sowerbutts
Hello world
I have been working on a CP/M program named "FLASH4" to rewrite the contents
of the flash memory chip in my Mark IV SBC. It works well for me and I think
it is ready for wider testing.
I've written FLASH4 so it should in principle work on any N8VEM Z80 or Z180
system that has hardware support for writing to the flash memory chip. I have
also tried to support a variety of flash ROM chips.
If you test FLASH4 please let me know. I will try to fix any problems you
find or add support for additional flash memory chips.
You can download the program, including a compiled "FLASH4.COM" executable
http://sowerbutts.com/8bit/flash4-v1.0.2.zip
FLASH4 is released as open source software licensed under the GNU General
Public License version 3.
A copy of the README.txt from the distribution file follows.
Will
------------------------------------------------------------------------------
http://sowerbutts.com/8bit/
= Warning =
** THIS SOFTWARE IS NOT YET WIDELY TESTED **
It is only well tested with 39F040 devices on the Mark IV SBC running RomWBW. I
believe it should work on other systems but I do not have any to test with. If
it works for you, please let me know. If it breaks please also let me know so I
can fix it!
Until it is more widely tested please ensure you have some other means to
reprogram your flash ROM before trusting FLASH4.
= Introduction =
FLASH4 is a CP/M program which can read, write and verify Flash ROM contents to
or from an image file stored on a CP/M filesystem. It is intended for in-system
programming of Flash ROM chips on N8VEM Z80 and Z180 systems.
FLASH4 aims to support a range of Flash ROM chips. Ideally I would like to
support all Flash ROM chips that are in use in Z80/Z180 N8VEM machines. If
FLASH4 does not support your chip please let me know and I will try to add
support.
When writing to the Flash ROM chip, FLASH4 will only reprogram the sectors
whose contents have changed. This helps to reduce wear on the flash memory,
makes the reprogram operation faster, and reduces the risk of leaving the
system unbootable if power fails during a reprogramming operation. FLASH4
always performs a full verify operation after writing to the chip to confirm
that the correct data has been loaded.
FLASH4 is reasonably fast. Reprogramming and verifying every sector on a 512KB
SST 39F040 chip takes 21 seconds on my Mark IV SBC, versus 45 seconds to
perform the same task using a USB MiniPro TL866 EEPROM programmer under Linux
on my PC. If only a subset of sectors require reprogramming FLASH4 will be
even faster.
FLASH4 can use three different methods to access the Flash ROM chip. The best
available method is determined automatically at run time. Alternatively you may
provide a command-line option to force the use of a given method.
The first two methods use bank switching to map sections of the ROM into the
CPU address space. FLASH4 will detect the presence of RomWBW or UNA BIOS and
use the bank switching methods they provide.
If neither RomWBW nor UNA BIOS is detected and the system has a Z180 CPU,
FLASH4 will use the Z180 DMA engine to access the Flash ROM chip. This does not
require any bank switching but it is slower. The Z180 CPU I/O base control
register should be configured to locate the internal I/O addresses at 0x40 (ie
ICR bits IOA7, IOA6 = 0, 1).
= Usage =
FLASH4 WRITE filename [options]
This will rewrite the flash ROM contents from the named file. The file size
must exactly match the size of the ROM chip. After the write operation, a
verify operation will be performed automatically.
FLASH4 VERIFY filename [options]
This will read out the flash ROM contents and report if it matches the contents
of the named file. The file size must exactly match the size of the ROM chip.
FLASH4 READ filename [options]
This will read out the entire flash ROM contents and write it to the named
file.
If your ROM chip is larger than the image you wish to write, use the "/PARTIAL"
(or "/P") command line option. To avoid accidentally flashing the wrong file,
the image file must be an exact multiple of 32KB in length. The portion of the
ROM not occupied by the image file is left either unmodified or erased.
One of the following optional command line arguments may be specified at the
end of the command line to force FLASH4 to use a particular method to access
/ROMWBW
/UNABIOS
/Z180DMA
If no option is specified FLASH4 attempts to determine the best available
method automatically.
= Supported chips and features =
FLASH4 will interrogate your flash ROM chip to identify it automatically.
FLASH4 assumes that you have a single flash ROM device and it is located at the
bottom of the physical memory map.
FLASH4 does not support setting or resetting the protection bits on individual
sectors within Flash ROM devices. If your Flash ROM chip has protected sectors
you will need to unprotect them by other means before FLASH4 can erase and
reprogram them.
AT29C series chips employ an optional "software data protection" feature. This
is supported by FLASH4 and is left activated after programming the chip to
prevent accidental reprogramming of sectors.
AT29F010
AT29F040
M29F010
M29F040
MX29F040
SST 39F010
SST 39F020
SST 39F040
AT29C512
AT29C040
AT29C010
AT29C020
The following chips are supported but have unequal sector sizes; FLASH4 will
only erase and reprogram the entire chip at once rather than its normal
AT49F001NT
AT49F001N
AT49F002N
AT49F002NT
AT49F040
If you use a flash ROM chip that is not listed above please email me
= Compiling =
The software is written in a mix of C and assembler. It builds using the SDCC
toolchain and the SRecord tools. A Makefile is provided to build the executable
in Linux and I imagine it can be easily modified to build in Windows.
You may need to adjust the path to the SDCC libraries in the Makefile if your
sdcc installation is not in /usr/local
= License =
FLASH4 is licensed under the The GNU General Public License version 3 (see
included "LICENSE.txt" file).
FLASH4 is provided with NO WARRANTY. In no event will the author be liable for
any damages. Use of this program is at your own risk. May cause rifts in space
and time.
_________________________________________________________________________
"Carpe post meridiem" http://sowerbutts.com
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_________________________________________________________________________
William R Sowerbutts will-***@public.gmane.org
"Carpe post meridiem" http://sowerbutts.com
main(){char*s=">#=0> ^#X@#@^7=",c=0,m;for(;c<15;c++)for
(m=-1;m<7;putchar(m++/6&c%3/2?10:s[c]-31&1<<m?42:32));}