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Altera_Forum's avatar
Altera_Forum
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15 years ago

UART wierdness

I'm trying to interface with a cell phone to the DE2 board over serial. I've been able to successfully talk to the phone using my computer and an FTDI cable. I know the baud and all of the other se...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

The UART module you selected in sopc is right.

The connection in sopc is right, too.

I can't check right now, but I think you can make some settings in the uart module, before generating the system (flow control, interrupt, ...): did you verify everything is correct?

After sopc generation you should see the uart pins (at least rx and tx) on the sopc symbol you include in Quartus. Are you sure these signals have been correctly connected and routed to the right fpga pins, I mean the pins physically connected to the DE2 serial port?

Regarding the signal levels, if you are using RS232, you don't have TTL, but bipolar levels:

high level : +5V to +15V

low level: -5V to -15V

(the actual absolute voltage depending from the driver)

I can't give you advice on the software code, since I never used the uart; so I don't know if your open() call is enough to init and start the serial port

Cris