LP-MSPM0G3507: No UART traffic when connected on MacOS

Hello Gabe,

J101 is used to bridge between the XDS110 side of the board and the MSPM0G side of the board. From your connection you would be tying the XDS110's RX and TX lines, not the MSPM0. I recommend using the uart_echo_interrupts example to test the UART connection to your computer's terminal. This example will echo the input characters back to your terminal. Below is an image of my launchpad jumper connections (default connections)

If you want to use the external loopback example, you would place the jumper on the other side of the J101, connecting the RXD and TXD on the MSPM0 side of the board. The example would not be viewable through your computers terminal though as it would not be connecting to the XDS110 side of the board.

To connect to the computer terminal, the UART signals would need to connect to the XDS110's RXD and TXD pins.

Regards,

Luke

I honed the issue down to the XDS110 itself. When on windows, and bridged the XDS110 TX/RX, I see an echo in my terminal. So the EVB UART bridge works and not broken.

Running on Mac the same experiment did not give me an echo. Hence I'm asking if the latest XDS110 firmware (I updated to the latest today) and the MacOS version I use have any know issue. Otherwise, I'd like to report it as an XDS110 firmware bug. Will be happy to follow guidance how to do it.

Basic troubleshooting of the Mac UART shows no concerns. The UART (usbmodemMG3500014) is connectable, but there's no traffic. Behavior is the same on two different Intel Macs and different OS versions: 13.4.1(c) and 12.6.8. At the same time the CCS debugging works fine. The issue is only with the UART part of XDS110, and only on MacOS. UART is fine on Windows.

System Information:

XDS110 (03.00.00.26) Embed with CMSIS-DAP:

  Product ID:	0xbef3
  Vendor ID:	0x0451  (Texas Instruments)
  Version:	1.00
  Serial Number:	MG350001
  Speed:	Up to 12 Mb/s
  Manufacturer:	Texas Instruments
  Location ID:	0x14144000 / 17
  Current Available (mA):	500
  Current Required (mA):	500
  Extra Operating Current (mA):	0

ioreg -p IOUSB
+-o Root  <class IORegistryEntry, id 0x100000100, retain 17>
  +-o AppleUSBXHCI Root Hub Simulation@14000000  <class AppleUSBRootHubDevice, id 0x1000003bb, registered, matched, active, busy 0 (8 ms), retain 19>
    +-o External USB 3.0@14700000  <class AppleUSBDevice, id 0x1000003bd, registered, matched, active, busy 0 (7 ms), retain 13>
    +-o Bluetooth USB Host Controller@14500000  <class AppleUSBDevice, id 0x1000003c1, registered, matched, active, busy 0 (10 ms), retain 22>
    +-o Keyboard Hub@14200000  <class AppleUSBDevice, id 0x1000003e4, registered, matched, active, busy 0 (9 ms), retain 15>
    | +-o Apple Keyboard@14220000  <class AppleUSBDevice, id 0x100000451, registered, matched, active, busy 0 (9 ms), retain 15>
    | +-o MOUS9 DONGLE@14230000  <class AppleUSBDevice, id 0x100000479, registered, matched, active, busy 0 (9 ms), retain 15>
    +-o FaceTime HD Camera (Built-in)@14400000  <class AppleUSBDevice, id 0x10000042d, registered, matched, active, busy 0 (9 ms), retain 18>
    +-o XDS110 (03.00.00.26) Embed with CMSIS-DAP@14100000  <class AppleUSBDevice, id 0x1000243a8, registered, matched, active, busy 0 (6 ms), retain 25>

ls -l /System/Library/DriverExtensions/com.apple.DriverKit-AppleUSBCHCOM.dext
total 56
-rw-r--r--  1 root  wheel    2559 Jul 11 01:35 Info.plist
drwxr-xr-x  3 root  wheel      96 Jul 11 01:35 _CodeSignature
-rwxr-xr-x  1 root  wheel  139872 Jul 11 01:35 com.apple.DriverKit-AppleUSBCHCOM
-rw-r--r--  8 root  wheel     537 Jul 11 01:35 version.plist

ls -l /dev/cu.*
crw-rw-rw-  1 root  wheel  0x22000001 Aug  6 13:06 /dev/cu.Bluetooth-Incoming-Port
crw-rw-rw-  1 root  wheel  0x22000003 Aug  8 16:42 /dev/cu.usbmodemMG3500011
crw-rw-rw-  1 root  wheel  0x22000005 Aug  8 16:43 /dev/cu.usbmodemMG3500014

Hello Gabe,

I'm working on getting a Mac to test this, I will reach out tomorrow if I can replicate this.

Regards,

Luke

Luke, can you help to clarify which of the two serial port instances should I expect the back UART connection? When the TI tools installed on the Mac, the first UART, usbmodemMG3500011 gets opened by some process, and can not be connected by the serial monitor. The other port, usbmodemMG3500014 was assumed to be the back UART. However, when I'm testing with another Mac with no TI tools installed, the first (usbmodemMG3500011) port is getting me the expected echo.