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Problem with using RS232 on DE2-70

Honored Contributor II

I have recently bought one of the DE2-70 boards for use in our embedded systems course, but I'm having a lot of trouble getting information through the UART. 


We are using the standard DE2_SD_CARD_AUDIO sample firmware on the DE2 (not DE2-70) boards at uni - and it works flawlessly, but when I try and load the corresponding DE2_70_SD_CARD_AUDIO sample firmware onto my DE2-70 board (given on the CD), the serial fails to work! 


I have noticed that the TX light stays on permanently on the DE2-70 (as soon as the firmware is loaded), but I'm not sure what this would mean. This does not happen on the DE2. 


When i try and read from the serial port, it DOES seem to open correctly, but it does NOT read from it. I have used the errno.h and errno variable to find that a "cannot allocate memory" error is occurring - even though this thing has ~64Mb of SDRAM. 


The open, read, write, etc. functions I am using are described on this page: 

h t t p : / / rabbit. eng. miami. edu/ info/ functions/ unixio. h t m l. 

(Spaces will have to be removed from the link above - I cant post links in my first 4 posts). 

Also note that it still occurs using stdio.h and the FILE handle aswell. 


If it makes any difference, I am loading the NIOSII stuff onto SDRAM_U1 (rather than the default SSRAM), because using the SSRAM seems to throw a "verify failed between address *some address*" error. 


Any help or advice would be greatly appreciated!!! 


Thanks in advance, 

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