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UART communication with MQX driver fails

Question asked by nico engel on Mar 28, 2012
Latest reply on Jun 8, 2012 by Jiří Kyzlink



I use MQX with the UART_0 for default output. So the bsp is configured with:

#define BSPCFG_ENABLE_TTYA              1



#define BSP_DEFAULT_IO_CHANNEL                    "ttya:"    /* OSJTAG-COM   polled mode   */




In my application the uart driver opens without error messages and I can step with debug mode into the uart sending functions. In the kernel function “_kuart_polled_putc(KUART_INFO_STRUCT_PTR io_info_ptr, char c)” I stop an read out the memory and register settings.


In this example (have a look at the screenshot) I try to send the value 0x78 (stored in char c) to uart output. But after step over the code line number 607 the register “sci_ptr->D” (UARTDataRegister) does not change and still stay on value 0x00. A forced writing of another value by a JTAG-debugger does not change too. The Register never change but the kernel function returns like everything was fine. The hardware never change his output-signal.


Does anyone know why the uart will not send any character? And does anyone know why I cannot overwrite this register by JTAG-debugger (J-Link Ultra)?


By the way: My measured pin on hardware is the right pin (pin PTA14). I tested this by using the gpio-driver. I have the same problem if I use another uart device.


Thanks for help.