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Forum Index : Microcontroller and PC projects : Problem with Olimex RP2040 PC and COM2
| Author | Message | ||||
| Frank N. Furter Guru  Joined: 28/05/2012 Location: GermanyPosts: 1177 |
Hi, for almost two weeks now, I've been desperately trying to connect an HX-20 to an Olimex RP2040 PC via a MAX3232.  On the Olimex, COM2 is routed through the UEXT interface. I'm trying to connect an HX-20 with an MAX3232 as a level converter to COM2. I was able to track the signals using the oscilloscope. The connections between the HX-20 and the MAX3232 are correct, but the signals aren't reaching the PicoMite! The moment I connect the Rx and Tx lines to the Pico, the MAX3232’s output signals (toward the Pico) are apparently pulled either toward GND or VCC. Without a connection to the PicoMite, I can see the data transmission by the flickering of the Rx LED. I also notice that when I reboot the Pico, the LED for one of the lines suddenly lights up (meaning the LED is pulled to GND) and goes out when I open the file manager. At this point, COM2 hasn’t even been initialized yet. When I start my program and send characters from the HX-20, I don’t see any activity on the LEDs. Unfortunately, swapping the Rx and Tx lines doesn’t help either. Has anyone ever successfully gotten the COM2 interface on this board to work? I’m using firmware version PicoMiteHDMIUSBV7.00.00RC7. Frank |
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