Hello, my questions are two part.
1. what is the smclk frequency for the 432 part for the launchpad dev kit for calculating the baud rate for the "backchannel uart"?
The demo says 24Mhz, but I am not so sure. Is there a pin I can connect a scope to to provide "ground truth"?
2. what pin is safe to connect a ground pin to when interfacing to the "backchannel uart"?
I tried two labeled grounds on the devkit each of which caused the CCS debugger to raise a JTAG error ->
Error connecting to the target:
(Error -1170 @ 0x0)
Unable to access the DAP. Reset the device, and retry the operation. If error persists, confirm configuration, power-cycle the board, and/or try more reliable JTAG settings (e.g. lower TCLK).
(Emulation package 6.0.228.0)
Then I gave up trying to connect a ground pin.
The context of what I am trying to do follows:
Basically, I used this demo as a template, changing the code to transmit ascii 0x30 "0" in a loop, hooking the transmit pin to "minicom" running on a linux box.
I first tried the default baud rate in the demo. This didn't work. Using the baud rate calculator, I found the code did not match the out put of the calculator, so I tried again, but it still failed. Then worrying that the baud rate was too fast, I slowed it to 9600, and it still failed.
The formula is from: http://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/MSP430BaudRateConverter/index.html
For every scenario I tried, I saw a stream of garbage characters. The demo unmodified obviously works for every baudrate because the receive and transmit are based on the same clock from the same board. But this doesn't help me because the minicom receiver is off-board.
I need to know what the clock is for the launchpad devkit for the 432 P401R, and how to verify it. The user guide does not provide enough information.
Any help?