There's also the unusual, little known but readily available and
programmable TMS2564 (Vpp also 25V, alas); it (sort of) stayed with
the original ROM/EPROM pinouts when everyone else switched to the
JEDEC standard as more pins became needed.
It's a 28 pin 8K x 8 EPROM, but the upper 24 pins are pin-compatible
with the MCM68764/6 and many 24 pin 8K x 8 ROMS (BTW, what's the
difference between the 68764 and the 68766?)
Of course you need the room for the extra 4 pins hanging off the end
and a jumper to the extra chip selects, but it's definitely an option,
especially as the Moto parts are getting scarce. I believe there's
also a Hitachi (?) version equivalent to the 6876x but I can't find
the number at the moment; probably even more obscure...
m
On Mon, May 27, 2024 at 11:35 AM jos via cctalk <cctalk@classiccmp.org> wrote:
>
>
>
> Gents, please be aware of the WSI 57C49 Eprom, 8Kx8 in a 24 pin DIP
> It can go low as 25nS access time.
>
> Note that addresslines A10,A11 and A12 are swapped, so the contents needs to
> be moved accordingly.
> I used the C program below to create replacements for some Tektronix 4052 ROMS
>
>
> Jos
>
>
>
>
>
> #include <stdio.h>
> #include <stdlib.h>
>
> /*
> * radapt <rominage>
> *
> * quick hack to transpose rom inages from mk36000 to wsi57c49
> * These are pincombatible except for A10, A11 and A12
> *
> */
>
> #define K8 8192
> #define K1 1024
>
> unsigned char in[K8], out[K8];
>
> void move(int a, int b)
> { int i;
> printf("%d %d\n",a,b);
> for (i=0;i<K1;i++)
> out[b*K1+i]=in[a*K1+i];
>
> }
>
>
> int main(int argc,char *argv[])
> {
> int i=0;
>
> int c;
> FILE *fptr;
>
>
>
> fptr=fopen(argv[1],"rb");
> { if (!fptr)
> printf("Unable to open file %s\n",argv[1]);
> else
> { while( (c=fgetc(fptr)) !=EOF )
> { in[i]=c; i++;}
> fclose(fptr);
> if (i!=K8)
> { printf("incorrect input file size, must be %d, not
> %d\n",K8,i);
> exit(-1); }
> move(0,0);
> move(1,2);
> move(2,4);
> move(3,6);
> move(4,1);
> move(5,3);
> move(6,5);
> move(7,7);
> fptr=fopen("out.bin","w");
> for (i=0;i<K8;i++)
> fputc(out[i],fptr);
> fclose(fptr);
> printf("Output file out.bin written\nmv out.bin %s\n",argv[1]);
> };
> };
> }
>
>
