68K, EASy 68K, and 16-bit wide EPROM's

[Steve Crompton]

Hi Folks,

I have a 16-bit wide EPROM attached to my 68000 system

D0   on EPROM wired to D0 on   CPU

.

.

.

D15 on EPROM wired to D15 on CPU

i.e. as you would expect!

I write code in EASy68K and use the EASyBIN utility to generate a BINARY file for my TL866 Programmer

When I load the file and burn it to the EPROM the bytes are the wrong way round

Now I am not using UDS or LDS so the whole 16 bits are put on the bus when an EPROM read occurs

I know I can fix this by simply rewiring the EPROM output data lines (bytes swap them) but this seems wrong

Am I missing a trick here but I would expect EASyBIN to get the bytes the right way round

All comments appreciated

Best Regards

Steve

[Alan Cox]

> I write code in EASy68K and use the EASyBIN utility to generate a BINARY file for my TL866 Programmer
>
> When I load the file and burn it to the EPROM the bytes are the wrong way round
>
> Now I am not using UDS or LDS so the whole 16 bits are put on the bus when an EPROM read occurs
>

> I know I can fix this by simply rewiring the EPROM output data lines (bytes swap them) but this seems wrong

There is no "right way around". It's equally valid each way and even processors can't agree on big or little end byte first. Even the x86 processor and the internet protocols disagree.

If you are running MacOS or Linux then

dd <easy68k.output >tl866.input conv=swab

should do the trick, and for Windows you can get yourself a 'dd' tool from somewhere.

I used to write code for machines with 36bit addressing, 7 or 9 bit characters. It's gets far more interesting at that point !

Alan