On Mon, Feb 25, 2019 at 11:53 AM Mike Brandon <[email protected]> wrote: > > Hi, > > TL;DR: What kind of signal is transmitted straight out of UART TX? > > I am beating my head against a wall with a circuit I have been designing > related to UART. I know my app works as I can use a USB-to-Serial adapter > connected to beaglebone's USB0 and my app performs as expected. When I > attempt to use UART4, via a MAX3232 chip, the app does not communicate as > expected. Prior to placing the MAX3232 chip in my circuit, I remember having > unsuccessful attempts with my app as well, leading me to believe that I > needed to convert the signal coming out of the UART with the 3232 chip. > > The device I am communicating with also has a 3232 chip onboard that my > signal is going through. I a thinking I am misunderstanding the signal being > produced by the UART4. I know I have at some point confused what results I > was obtaining when I had the circuit breadboarded and was testing things out. > So I think I am just needing to start fresh and do some better documenting of > my tests going forward. > > However, at this current point in time, I do know my MAX3232 circuit works as > I have tested by looping the RX/TX lines on the other side and I can > send/receive in minicom on the BBB. I also communicated with another PC via > the circuit successfully. In that setup, the BBB was sending through the > MAX3232 which the RX/TX output was connected to a USB-to-serial adapter that > was connected via USB to a windows PC. > > I have also a better documented thread of the issue here, for reference: > https://forum.allaboutcircuits.com/threads/max3232-to-max3232.156598/ > > At this point, looking at my circuit and the device I am attempting to > communicate with, I believe I am sending a TTL signal to the device > connection which is expecting a RS232 signal. > > Mainly I am just trying to understand what kind of signal is transmitting out > of the UART TX, is it TTL or RS232? I did look at the BBB system ref. manual > but did not see data related to this.
On the bbb it's 3.3v TTL Regards, -- Robert Nelson https://rcn-ee.com/ -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAOCHtYj0O5RX7Yoa-E3d5VugJdDh_U4R-ShykfU%2BRVQzC2Tpzg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
