[meta-freescale] I.MX6 SoloX M4 Problem
Nathan Barrett
nbarrett at microcomcorp.com
Mon Mar 23 10:53:14 PDT 2015
Hello Everyone,
I believe I may have run into a pin multiplexing problem with the I.MX6SX SDB, 3.10, and imx6sx-sdb-m4.dtb
I have managed to boot Linux on the A9 and a demo application on the M4.
If I boot the M4 application via 'run m4boot' in u-boot before Linux is booted, the input/output on the M4 side seems fine at 115200 baud on the FTDI usb-serial
debug port.
***** MCC Virtual TTY EXAMPLE *****
Please wait :
1) A9 peer is ready
Then press "S" to start the demo
********************************
Press "S" to start the demo :
However -- As soon as the A9 core starts running Linux, any input/output on the M4 side looks like gibberish. It's as if the baud rate is no longer set to 115200.
For example if I press 'S' before issuing the boot command in u-boot (to start Linux) the response is "Responder task started, MCC version is 002.000" from the
M4
If I press 'S" after Linux is booting, I get no response and the S does not appear as an 'S' in Teraterm. Again, it's as if the S isn't making it through because the
baud rate is mangled.
To clarify this issue a little more. I wrote a program on the M4 which prints "Hello World" every 100 ms. I then set u-boot to automatically start the M4 and the
A9. The M4 starts first.
What I see when turning the board on is:
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
Hello World
ÈùÙloùÙ
ÈùÙÈùÙÈùÙÈùÙÈùÙÈùÙ
ÈùÙÈùÙÈùÙÈùÙÈùÙÈùÙ
ÈùÙ ÈùÙÈùÙÈùÙÈùÙÈùÙÈùÙ
ÈùÙÈùÙÈùÙÈùÙÈùÙÈùÙ
ÈùÙÈùÙÈùÙÈùÙÈùÙÈùÙ
ÈùÙÈùÙÈùÙÈùÙ ÈùÙ
ÈùÙÈùÙÈùÙÈùÙÈùÙÈùÙ
ÈùÙ ÈùÙÈùÙÈùÙÈùÙÈùÙ
ÈùÙÈùÙÈùÙÈùÙÈùÙÈùÙ
The gibberish repeats indefinitely. Changing baud rates does not fix the issue.
Does anyone have any idea what's going on here?
Thanks
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