TMS9900 chip with additional marking MP9514

[Stuart]

Does anyone have, or know anything about, TMS9900 chips with the additional marking "MP9514". It will probably be a ceramic chip with a gold top. I've been contacted by a chap who's after one to repair some equipment. Apparently it's not interchangeable with the standard TMS9900 chip (although its still 64-pin, 0.6" wide). I seem to recall that the MP number relates to a mask number so its probably different internally somehow.

 

Stuart.

[matthew180]

If Google does not turn up something, good luck finding any "offline" info. Someone would have to have the old datasheet or something. I have to imagine sourcing one will be even harder. If the differences were known, it might be possible to modify a standard 9900 to work?

[+FarmerPotato]

Found it!  (12 years?)

 

The MP9514 is the Logic Processor in TI's PM550 PLC (Programmable Logic Controller).  It is mentioned as one of two 16-bit processors, in the Program Master 550 Intelligent Programmable Control System Programming Manual.

MP9514

 

The MP9514 Logic Processor continuously scans all steps of a Relay Ladder Logic (RLL) program in non-volatile RAM.    Separately, the TMS9900 Controller runs an Executive OS which handles functions such as PID loops and math.    The MP9514 and TMS9900 share a common memory bus.

 

The MP9514 interrupts the TMS9900 when it reaches a Step that represents a subroutine call.  The Executive queues the request.  When the request is completed, the Executive updates a memory location.  The MP9514 sees it on its next scan.  

 

@Stuart, @matthew180 I'm excited to learn that both processors are TMS9900.

 

Texas Instruments PLCs

 

I've been writing about these on our sub-forum.   Your post here, Stuart, was the only Google result for MP9514!

 

 

 

 

TI-PM-550-programming-manual.pdf

[Stuart]

Good job I wasn't holding my breath!