| ??? 11/08/05 16:42 Read: times |
#103429 - what is universal? Responding to: ???'s previous message |
Erik Malund said:
JTAG has never been "intended" for programming/debugging, thus the debug/programming is nonstandard and the likelyhood that multiple manufacturers have implemented it the same way is very small. Agree. However, universal way for programming is still possible - using a standard STAPL/JAM output from the "programming software" and feeding it into some "STAPL/JAM" player (see e.g. recent thread here for svf/xsvf files "playback"). STAPL and JAM just describe the sequences on the JTAG pins, so the "player" does not need have any knowledge on the chips' internals. This does not apply for debugging (*), which is very device specific and most manufacturers publish no or unusably limited data on it. (*) In theory, debugging using JAM would be possible, but the manufacturers don't care to support it at all, they want to promote their proprietary tools. Erik Malund said:
The hardware should be, at least, very similar, since all I know allow JTAG chaining which would be impossible with nomnstandard signal path. All that needs to be similar (or standard-conforming) is the JTAG state machine inside the chip. The "dongles" used for programming are - again - proprietary... But if there are of the "parallel-port-plus-buffer" type, at least a configurable "parallel-port-pin-multiplexer" can be built to decrease the need for switching different "tools" ("cables", "dongles") on the port - try googling for "chameleon". Jan Waclawek |
| Topic | Author | Date |
| Universal JTAG Hardware? | 01/01/70 00:00 | |
| the debug/programming is nonstandard so | 01/01/70 00:00 | |
| Several with JTAG | 01/01/70 00:00 | |
| what is universal? | 01/01/70 00:00 | |
| Universal | 01/01/70 00:00 | |
| as far as the cable, why not, that is in | 01/01/70 00:00 | |
| Choice of words! | 01/01/70 00:00 | |
| that would be silly from SiLabs | 01/01/70 00:00 | |
| HUH? | 01/01/70 00:00 | |
| the 4 JTAG pins | 01/01/70 00:00 | |
| Ok | 01/01/70 00:00 | |
debug | 01/01/70 00:00 | |
| Silly seems to fit | 01/01/70 00:00 | |
| Now this sounds really silly... | 01/01/70 00:00 |