To your experience, which 8051 in circuit emulator is giving faithful result, yet low cost (<$10K)? I am using Philips 8xC58 family microcontrollers. Thanks.
Higher-end processors have already gone the JTAG (etc) route, if for no other reason that you can't make a bond-out ICE for high speed, complicated processors for any reasonable cost. If the trend for such cores as ARM and PPC hold true, then the JTAG debuggers are going to be more limited than the old-school ICEs. In particular, I don't see very many hardware vendors that actually support trace and timing functions in the chips, even when the available debugger software has those features. Usually, they give you two (or one!) hardware breakpoints and leave it at that. The trace modules are an available option that the actual chip designers seem never to actually put in the chip, available in theory but not in practice. Since the on-chip debugging moves the debug hardware from the ICE to, well, on-chip, it adds to the cost of every chip. The extra gates for fancy internal trace functions are going to hurt a lot more on an 8051 die than on say, an ARM9. It'd be a much higher percentage of your total gate count, and affect your final per-unit price that much more. So, I'd expect there to be even more pressure to leave extra on-chip features out of small micros. So, I think it unlikely that you'll have extensive debug capabilities on the same part you actually use for production, if you have them at all. Manufacturers may decide to develop special debug parts that have more on chip support, and sell them at a higher price, just for development. (This path of course has many of the same drawbacks mentioned for the special bond-out part for an ICE.) But I don't see that going on in the ARM or PPC marketplace, so I don't really expect it in the 8051 marketplace. I'm afraid I'll just have to say goodbye to the ICE, replacing those functions with intrusive (and result-affecting) software instrumentation and somewhat more awkward logic analyzer tracing (for those designs that aren't so highly integrated that you can still see the bus signals). And if you think an ICE is expensive, look at the price on a good logic analyzer...
I'm afraid I'll just have to say goodbye to the ICE Why, Drew ? Erik
Why? Well, the reasons I was outlining above. JTAG emulators have a lot of good things going for them. And if the chip makers go that route, and thus aren't making emulator parts, the ICEs will disappear.
The JTAG is an added expense to the chip and we (some of us) are in very cost conscious fields where $0.50 per chip is real money. So far, I have only seen JTAG on the very expensive derivatives (Cygnal) and I doubt it will be seen soon on the $0.58 chips. Erik
An low-cost alternative for standard 40-pin DIP and 44-pin PLCC 8051 devices is the SoftICE from SST that connects directly to the µVision2 Debugger. See: http://www.keil.com/pr/sst_020315.htm