Hello All, After several months of developing with the MCB2130 eval board I finally got my first prototype hardware. I am pretty excited, but I have a couple issues. My first big issue is the SPI output signals. I am communicating with two other devices over an SPI bus where the LPC is the master. The signals coming out of the LPC are correct, except the peak voltage of the MCLK and MOSI are about 1Volt! Orignally, I had buffers on all the SPI lines, but due to cost pressure I had to take them out. I read that the max output current for the LPC pins is like 4mA. Question: Are the LPC2131 outputs really that wimpy? Has anybody else had this problem? Did you just add buffers? Second issue is with the JTAG interface. The ULINK worked flawless with the MCB2130 eval board running with 12MHz crystal. But my hardware uses a 12.288MHz crystal. I have changed the crystal and PLL settings in startup.s and the debugger but, I is still very unreliable. I have gotten it to work about 3 times out of 50? Mostly, I download my code using the Philips Flash Utility over the serial port. Also, I worked thru all the suggestions in the Keil knowledgebase regarding "JTAG Communication Failure" with the ULINK. None of these things fixed it. I suspect it has something to do with the clock settings. Does anybody know of any other tricks or secret clock settings in uVision3 or startup.s? Thanks, Dave Butler
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LPC2131 SPI output drive and ULINK JTAG issues
2005-07-20 by drb5599
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