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Hi, If it's the same as the 2294 (which seems likely), you have remember that the processor looks at the state of pin P1.26 (which has to be low) on reset to go into JTAG mode. Also, the datasheet says you should do a read/modify/write on the PINSEL register. It took me absolutely ages to get my head round this! This is what I did for the 2294, which works for me! I'm sure you'll have to modify slightly differently for 2194. (In fact checking the datasheet it looks like bits 2 and 3 are the only relevant ones for you). // Now PINSEL2 which configures debug lines and address and data lines temp = PINSEL2; temp |= 0x0F814920; temp &= ~0x08; // Take it out of trace mode... PINSEL2 = temp; For me, the thing that finally got it working was the line: temp &= ~0x08; // Take it out of trace mode... You must remember that you *only* want to take it out of trace mode, not out of debug mode as well If you write all zeros to PINSEL2 (in fact if you write a zero to bit 2, you'll take it out of JTAG mode. This wasted a lot of my time sussing this out. Also, note that the processor looks at the state of P1.20 to see whether it should use trace mode for P1.25:16. Hope this helps. Cheers, Rob Hi, I'm trying to work out a problem I'm having programming a LPC2194. I've posted a question on this already here. See: http://groups.yahoo.com/group/lpc2000/message/4049 I was looking in the LPC22194 & LPC2294 datasheets and I saw that the JTAG pins (P1.26-P1.31) PINSEL register was set to P1.26/RTCK at reset. The LPC2194 datasheet says the JTAG's PINSEL register is set to '0' on reset. Does the JTAG PINSEL register on the LPC2194 need to be set to '1' for me to program the LPC2194 via JTAG? The datasheet says the PINSEL is set to '0' at reset, this seems wrong to me. Seems it should be the same as the LPC2294. That way it always comes up with the debug port enabled. I was setting the PINSE2 register to 0x00000000 after my program was up and running because I need to use some of the TRACESYNC pins as IO. If I put in a new LPC2194, take out the setting PINSEL2 to 0x0000000, will the JTAG work? I'll try this later and see if it works. I just hate to pull any more LPC2194's off of the PCB... Yahoo! Groups Links |
