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{{Message/Information Message|title=TITLE|message=This How-To was tested under Kernel 2.6.35.y but content are valid for Kernel 2.6.37.y}}
= Overview =
This How-To is meant to be a starting point for people to learn to set up UART2 for IGEPv2 J990 connector as quickly and easily as possible. In this how-to, we use [http://releases.linaro.org/platform/linaro-m/headless/final/linaro-m-headless-tar-20101108-2.tar.gz Linaro Headless] with [[Linux Kernel 2.6.35.y|Kernel 2.6.35.y]]. This How-To is focused for revisions RC1/RC3/RC4/RC6 (WIFI/BT versions). <br>
More information about UART: [http://en.wikipedia.org/wiki/UART UARTUniversal_asynchronous_receiver/transmitter <span style="text-decoration: underline;">here</span>] and [[How to use UARTs|here]].'''<br>'''
There are two three modes to configure UART2 in J990: via user space (fast modefirst way), editing only igep.ini (second way) or editing kernel source and compile it (slow modethird way). '''NOTE: '''UART2 in j990 connector has CMOS voltages (0V-1V8).
= Feedback and Contributing =
At any point, if you see a mistake you can contribute to this How-To.<br> = First way<br> = First way: this mode has an issue, when your system reboot or shutdown you will need to configure again. Using user space to configure mux and disable bluetooth.<br>
=== Configure IGEP ===
Logging with root user via SSH or Serial cable.<br> '''Disable BluethootNOTE:''' Poky distribution does not have debug filesystem enabled. Mount it: <pre>mount -t debugfs none /sys/kernel/debug</pre> Go to /sys/kernel/debug/omap_mux/<br>
Set sdmmc2_dat5 to GPIO137 gpio137 (mode(4):
<pre>echo 0x004 > sdmmc2_dat5 </pre>
<pre>root@localhost:/sys/kernel/debug/omap_mux# cat sdmmc2_dat5
name: sdmmc2_dat5.gpio_137 (0x48002166/0x136 = 0x0004), b ah3, t NA
signals: sdmmc2_dat5 | sdmmc2_dir_dat1 | cam_global_reset | sdmmc3_dat1 | gpio_137 | hsusb3_tll_stp | mm3_rxdp | safe_mode
</pre>
Go to: /sys/class/gpio/
export gpio137 gpio138 gpio139 gpio170 gpio64 gpiochip0 gpiochip128 gpiochip160 gpiochip192 gpiochip32 gpiochip64 gpiochip96 unexport
root@localhost:/sys/class/gpio#