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Altera_Forum
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15 years ago

printf() problem after IOWR and IORD

Hi I faced to a problem with prinf() function.. in my C code when I wrote printf() after IOWR nothing was displayed out. but all the printf()s before IOWR were displayed in the jtag window. I ...
Altera_Forum's avatar
Altera_Forum
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15 years ago

According to the avalon specification document,readdatavalid is used for piplining the transfer,and it is not used in normal transfers,anyway when I assign logic '1' to the readdatavalid or remove it completely,the whole design stops during the simulation and these erros appear in the modelsim window: 

#  245810 ns: WARNING: cpu_test_bench/M_wr_data_unfiltered is 'x'#  245820 ns: ERROR: cpu_test_bench/W_wr_data is 'x'#  Break in Module cpu_test_bench at ../cpu_test_bench.v line 522

how can I use this signal?

In the document of avalon, there is an example which illustrates READ and WRITE transfers without using readdatavalid signal!