On Sep 7, 2011, at 3:20 PM, V G wrote:

>> [a true ICE] emulates the real PIC, typically with a special silicon.
>>
> What is the purpose of this?


cycle-by-cycle visibility of the chip internal state.  Code in RAM for =20
easy reloading.  Infinite breakpoints, backtrace and other logic-=20
analyzer-like functionality, all operating in real time (or near real =20
time.)


> Were the old PICs incapable of in circuit debugging?


Yes, they were incapable.  The idea of having an "intelligent" on-chip =20
debug module accessed via a very small number of external pins =20
(perhaps multiplexed with normal functions) is relatively recent.  The =20
debug module on a mid-sized ARM probably has more transistors than =20
many of the early PICs.

BillW

--=20
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