copy eproms

[Timothy J Burgess]

Or you may use the larger PROM to store two separate loads of code (or four
loads with a 27C512) & easily select between the two.  Here's how I built
up the multiple load selection hardware:  Attach a 5 x 1 header to a 28 pin
DIP socket near pin 28 - connect header pin 1 to socket pin 28 (+5 volts),
connect header pin 3 to socket pin 27 (programmer address msb; A14),
connect header pin 5 to socket pin 14 (gnd), connect header pin 2 to header
pin 4.  Attach the wires to just below the body of the socket.    Bend up
pin 27 (address 14) of the PROM.  Install the PROM in the socket.  Solder a
wire between pin 27 of the PROM and pin 2 of the header.  Use a jumper
(shorting) block to select the PROM mode:  Short header pins 1 & 2 = Use
load @ address 0x4000 to 0x7FFF.  Short header pins 4 & 5 = Use load @
address 0x0 to 0x3FFF.  Short header pins 2 & 3 = Program PROM.  Load both
16K PROM loads at the starting address indicated above (0x0 & 0x4000) in
the PROM programmer memory before programming the 32K PROM.  If a 27C512
PROM is used, A15 is the address msb & it is located at pin 1 of the 28 pin
DIP.  The PROM data sheets (pinouts) may be found at
http://www.atmel.com/atmel/products/.

Tim


Date: Tue, 4 Dec 2001 09:15:30 -0000
From: "Richard M" <richm at ntlworld.com>
Subject: Re: copy eproms

Yes, but depending on what the ECU does with the extra address line, it may
not work if you only copy the bottom 128K into the larger eprom - best to
duplicate the 128K code onto the 256K part (same in the lower 128K and
upper
128K), so the code will be the same from the ECU's perspective,
irrespective
of what state the most significant address bit is in.
Regards
Rich
- ----- Original Message -----
From: Tom Cheung <tomcheung at telus.net>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, December 04, 2001 6:49 AM
Subject: copy eproms


> can i copy data from a 27c128 eprom to a 27c256 eprom easily?
> i will purchase a needhams programmer to do this
>
> the 128k eprom is harder to get and may be more expensive

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