i8049 and i8749 Interchangeability

[NeXT]

I'm noticing that my Digelec 824 supports working with the 8748, 8748H and 8749H which (that I can tell) are the EPROM versions of the 8048 and 8049. So far other than having UV erasable program storage they seem to be identical chips but the Intel MCS-48 family whitepapers stops short of mentioning the 8049 at all. I guess it was not available yet?
I don't need to write to either chip type. I just need to dump the internal 2K ROM on the 8049 which should be as simple as set the chip type, drop the MCU in, read into the programmer's buffer and send that to the host PC? Be a hell of a lot nicer than paying $70cad for a Willem adapter.

 

[Al Kossow]

8049 is the 2K ROM version
Intel 8049s can be read as 8749s, I do it all the time.

There was also no copy protection on that generation of microcontrollers.

 

[NeXT]

But am I correct in setting the Digelec to 8749H mode to dump an 8049 and not expect things to go pop?

 

[twolazy]

I dunno, the 8749h has a 18v programming, where as the 8049 has 21v. Its close enough I doubt it would pop, but I would throw on a 20ohm or so resistor just to be safe. As long as you have another socket you can pull a leg up on, and solder a resistor too, should be safe.

EDIT But you arent programming and both are 5v, so should be fine. Half awake.

 

[Dwight Elvey]

Just to be safe, you should make a socket that just connect the programming voltage pin for the 8049 to the correct level ( 0 or 5V, I don't have the specs handy ). You just lift the pin so it is not directly connected to the programming level of the programmer and then wire to the appropriate level. You can't hurt the 4049 that way, by accident.
Dwight

 

[daver2]

Sometimes, verification mode is also performed at a higher voltage...

Dave