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Altera_Forum
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14 years ago

Strange problem with IORD_16DIRECT

Hi, I have a 16-bit pio (input) in my sopc and I want to access the data through IORD_16DIRECT. The data shown on the port is 0x00, 0x01, 0x02....0xff (verified through signaltap). However, th...
Altera_Forum's avatar
Altera_Forum
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14 years ago

Hi Daxiwen,

This code (if(data_temp&0x100==0x100)) is for synchronization, I keep reading the port, if the 9th bit is high, it means data is coming.

For the speed, I got the same result when I use 500K and 2M clock in my verilog code. So I guess it is not the reason. Is there any special mechanism for PIO 16bits?

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I don't see any synchronization system in your code, so you have no way of defining or detecting when you read the PIO port.

If the PIO port input changes faster than your software can read it, then you'll miss some values.

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