Thursday, August 24, 2006
Ok, so I was using CrossWorks v1.5 and that was a major source of my problem. If you want to
easliy use the LPC-H2249 CrossWorks v1.6 is the solution. I am still waiting to get some time to build a toolchain on a linux box to compile code for the LPC-H2294. But for now CrossWorks is close enough. So here is the deal If you would like a simple hack to use the UART with the pins provided from the LPC-H2294 must have the right voltage to talk to the serial device of the computer, if thats what your interfacing with. The serial from the pc is 12v and a usb-to-serial provides that 12v when you use it. The LPC-H2294 UART pins are 3.3v so you need to kick it up or down. Instead of building a curcut to do this you can crack open your usb-to-serial and see what kind of chip it has. As far as I know MAXIM Transceivers provide a different voltages on differnt pins. So what a friend of mine suggested was to use those pins instead of what is connected to the serial part of the device. I had a MAXIM MAX213 Chip and used pin 19 for the RX on the UART. Pin 6 was used for the TX on the UART.
My explanation sucks, but my pictures rock! http://xsignal.mindtunnel.org/ARM/UART_SERIAL_HACK