On Sat, May 25, 2024 at 6:27 AM emanuel stiebler via cctalk <cctalk(a)classiccmp.org> wrote: What is an SCM90448? Can you find a datasheet for that part? I cannot.

On Sun, May 26, 2024, 4:06 AM emanuel stiebler <emu(a)e-bbes.com> wrote: Oh, so a Motorola MCM68764 / MCM68766?

On 2024-05-26 12:30, Glen Slick via cctalk wrote: I have one board with MCM68766 and two boards with SCM90448 Excellent! Yup! Actually hoping for: MicroPDP-11/23 ROM v1.1 (23-453E4 and 23-454E4

Just curioius, as a much less techy person, are there sets of eproms that are compatible for reading, but just require a different programming regimen? Could the OP have used a different eprom that is easier to program? If not, is the limitation pinout, so a header swapping pins could let a different eprom be used?

Just curioius, as a much less techy person, are there sets of eproms that

Could the OP have used a different eprom that is easier to program?

I would love to have copies of the image HEX files so I could get some of mine running again.

On 5/27/2024 5:47 AM, emanuel stiebler via cctalk wrote: wrote: I would love to have copies of the image HEX files so I could get some of mine running again. bill

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]); }; }; }

On Mon, May 27, 2024, 12:56 PM Mike Stein via cctalk &lt;cctalk(a)classiccmp.org&gt; wrote: From what I can tell from a quick look at the datasheets, on the 68764 the /E pin is both a low power mode pin and an output enable pin, while on the 68766 the /G pin in just an output enable pin. So there might be less average power consumed when using the 68764, but the 68766 data output valid from /G might be quicker than the 68764 data output valid from /E if the address lines are stable earlier than /E or /G are asserted.