UART2 , Linux 2.6.32

Just wondering if there is some special magic to get UART2 working
(/dev/ttyS1) on Linux 2.6.32 Angstrom. I am using a BB Rev C4 and
connecting to expansion connector pins 6 (tx) and 8 (rx). The tx pin is
working fine but am unable to receive data on the rx. I have setup my
muxing in u-boot as follows:

MUX_VAL(CP(UART2_CTS),(IDIS | PTU | EN | M4)) /*UART2_CTS*/\
MUX_VAL(CP(UART2_RTS),(IDIS | PTU | DIS | M4)) /*UART2_RTS*/\
MUX_VAL(CP(UART2_TX),(IDIS | PTD | DIS | M0)) /*UART2_TX*/\
MUX_VAL(CP(MCBSP3_FSX),(IEN | PTD | DIS | M1)) /*UART2_RX*/\

MUX_VAL(CP(UART2_RX),(IDIS | PTD | DIS | M4)) /*alternative UART2_RX*/\
MUX_VAL(CP(MCBSP3_DX),(IEN | PTD | DIS | M4)) /*OLD UART2_CTS*/\
MUX_VAL(CP(MCBSP3_DR),(IDIS | PTD | DIS | M4)) /*OLD UART2_RTS*/\
MUX_VAL(CP(MCBSP3_CLKX),(IDIS | PTD | DIS | M4)) /*OLD UART2_TX*/

I am running this through the proper level shifters and then through a
232 driver chip. This problem exists on two different in house built
expansion boards and like I stated, the tx is working as expected, so I
doubt the hardware is an issue.

I am using minicom on both ends and have turned off all flow control.

Proper data is being sent out and collected fine but it appears within
Linux somewhere the serial driver is not seeing any received characters.

I have switched the muxing around to turn pin 8 (MCBSP3_FSX) into a
GPIO_143 (Mux mode 4) and I am able to toggle the level of that pin
(ball AE5) on the expansion connector as expected.

At a loss here, thanks for any help that might pop up.

Ross

Silly but you don’t mention ground?

Everything is grounded properly.

Okay now, I know someone knows the secret. I'll rephrase the question.
By just changing the mux settings in u-boot, should UART2 tx and rx be
available on the BB C4 expansion pins 6 and 8 respectfully?

And, has anyone made this work with the Angstrom distro version 2.6.32?

Thanks again.

Have you checked here?

http://elinux.org/BeagleBoardPinMux#UART2

Gerald

You don't even need to change the muxing: http://m.flickr.com/#/photos/koenkooi/5886944997