I'm using a FRDM-K64F with a handful of peripherals. At the moment, I cannot get UART4 to work. I have PEx set up to use PTE24 and PTE25:
I'm using the same settings (with the exception of pins) for UART3 for an RS485 transceiver, and it works just fine. But when I look at the output of TX on the scope, I get nothing.
Can anyone suggest something that I might be doing wrong? Here's what I have done so far:
Solved! Go to Solution.
Hi David,
I have UART4 successfully working on PTC14/15 of FRDM-K64F Freedom board.
Looking at Freedom schematic the PTE24/25 connect to FXOS8700CQ pins 4/6 that also have 4.7k pull-ups that might be messing with you.
My simple test was hardwiring PTC14/15 at J199 pins 3-4 for a hardware echo test.
Regards,
David
Hi David,
I have UART4 successfully working on PTC14/15 of FRDM-K64F Freedom board.
Looking at Freedom schematic the PTE24/25 connect to FXOS8700CQ pins 4/6 that also have 4.7k pull-ups that might be messing with you.
My simple test was hardwiring PTC14/15 at J199 pins 3-4 for a hardware echo test.
Regards,
David
Thanks, David, as usual you were spot-on. I should have remembered that there were other I2C peripherals on the FRDM. I never use them and had completely forgotten.:smileysilly: I guess the settings were correct since I hooked up the peripheral and it immediately responded to my serial command once I moved over to PTC14/15.
On another note, did my PEx configuration look reasonable enough to you?
Yes.
My setup was close but I was using interrupts with callbacks only because another customer wanted to see that work.
Note the Bluetooth is just a name.
Regards,
David
Yup, I know the port is general purpose and not just for BT, much like the one that's there for the nordic RF breakout board. I have to play with callbacks later -- at the moment I'm using a thread that waits forever for incoming data to arrive on the Rx pin. If you have comments about the downside of such an implementation, I'd love to hear your thoughts.
Thanks for the tip, David! I hadn't considered that, or the Bluetooth header you used for your test. I'll give that a try.