Timeline for MSP430 UART Trouble
Current License: CC BY-SA 4.0
14 events
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| May 19, 2022 at 14:05 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Oct 18, 2021 at 5:59 | answer | added | dman | timeline score: 1 | |
| Oct 14, 2021 at 5:35 | comment | added | dman | I can successfully receive the serial signals with a raspberry pi, but random characters show up. When I try always sending 1 instead of a count value, the received signal is usually 0xfc, with a few 0xf8's thrown in randomly. I have a ground and 3.3V pin on the MSP430 and raspberry pi connected so they should be at the same voltage level. If the raspberry pi always received the same value I could easily rearrange the order of the bits, but receiving different values when always sending the int 1 is weird. | |
| Oct 12, 2021 at 3:07 | comment | added | dman | With the hardware I have, I think the easiest way to see if the problem is my computer is to try receiving the UART signal with a raspberry pi's UART pins. I'll make sure to comment again once I try it. | |
| Oct 11, 2021 at 22:11 | comment | added | jonk | @dman I developed a reliable and working system to mediate between the Centronics style parallel printer port of a MailStation (see an old article about one of them here) and a PC via the USB port. To do this, I used two MSP430 chips -- one on a custom-designed board to monitor the parallel port and the other using the TI Launchpad system to provide the serial port/USB services I needed. I have had no problems at all with the system. So it does work well. That code dates to 2013. But I can unearth it when I get a moment. | |
| Oct 11, 2021 at 20:30 | comment | added | Jasen Слава Україні | MSP430 launchpad has in my experience a very unreliable USB-UART bridge implementation, at-least in the promiotional $4.30 version of the launchpad. | |
| Oct 11, 2021 at 10:03 | comment | added | jonk | @dman When you are using USB, you must be using a virtual COM port. This pretty much means that there is another device on the board that is tied to your UART port, and translating that into USB transactions into the PC which are then made to appear as if they are COM ports. But they are not. Not really. It's all faked. You are not really talking to the PC, directly. But via another IC and a bunch of software someone else wrote to mediate between you and the USB transaction system. The PC itself will use a standard HID driver, too. This complicates your question a bit. | |
| Oct 11, 2021 at 9:45 | comment | added | dman | @jonk I'm using a USB COM port on my computer to try receiving the signal, and the LaunchPad's backchannel UART to send it, so the signal is traveling over the same USB cable that Code Composer Studio uses to program and debug the board. I have the jumpers on the LaunchPad set to use software UART. The backchannel UART shows up as a separate COM port in the computer's Device Manager, and that is the COM port I am setting up PuTTY for. | |
| Oct 10, 2021 at 10:13 | comment | added | Jasen Слава Україні | Check that the uart port is toggling, send "UUUUU" repeatedly and measure the frequency of the signal (should be half baud rate) | |
| Oct 10, 2021 at 9:39 | comment | added | jonk | @dman I don't want to bother reading your code and refreshing my memory via the TI manuals until I better understand what you are doing. I use PuTTY myself on a PC. But it is usually being used with virtual COM ports over a USB connection mediated by other ICs. Not real COM ports. You mention an MCU but not a board design. So I need to know exactly what is connected and how it is connected up. Are you using virtual COM ports? Or a real serial port using RS-232 signaling? Convince me. | |
| Oct 10, 2021 at 9:31 | comment | added | dman | @Jasen I tried adding 'P1DIR = BIT0 + BIT2; //set P1.0 for output for LED and P1.2 for output for UART Tx P1SEL = BIT1 + BIT2; //Set P1.1 and P1.2 for UART P1SEL2 = BIT1 + BIT2; //Set P1.1 and P1.2 for UART' before the line 'UCA0CTL1 &= ~UCSWRST; //take UCA0 out of reset state' but it still doesn't work. | |
| Oct 10, 2021 at 6:24 | comment | added | Jasen Слава Україні | you need to set the pin into UART mode. | |
| Oct 10, 2021 at 3:55 | history | edited | dman | CC BY-SA 4.0 |
added 2 characters in body
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| Oct 10, 2021 at 3:46 | history | asked | dman | CC BY-SA 4.0 |