11-04-2015, 05:04 PM | #1 |
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Onyx Boox J25 Serial Port?
Hi all. I'm trying to use the J25 header on the right-hand side of my T68 as a serial port so that I can connect a GPS device. Apparently, other Boox devices also have the J25 header, e.g. the M96.
Does anybody have any details of this, e.g. pinouts. I believe on the T68 that it's 3.3V levels and connected to /dev/ttymxc0, but I have had no luck in working out which pin does what. Many thanks in advance for any suggestions and pointers. Warren |
11-05-2015, 03:20 PM | #2 |
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Do you mean this header: http://c2n.me/3pUjmGt.jpg ?
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11-05-2015, 04:17 PM | #3 | |
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Quote:
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11-13-2015, 08:35 PM | #4 |
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Anybody else with any information on the J25 header on any Onyx device?
Thanks, Warren |
11-18-2015, 04:15 AM | #5 |
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11-18-2015, 06:23 AM | #6 |
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Many thanks Booxtor. And what Linux /dev device is it? /dev/ttymxc0 at 115,200 baud? 3.3V levels?
Cheers, Warren |
11-18-2015, 07:33 PM | #7 |
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Hmm, I'm still not having any luck. I've soldered in three wires to the RX, TX, and GND pins. I've killed off the shell using /dev/ttymxc0 and I've renamed the character device so that the shell doesn't reopen it.
How: lsof | grep ttymxc0 to get the shell's PID mv /dev/ttymxc0 /dev/fred kill -9 shell's PID microcom -s 115200 /dev/fred I did a loopback test using microcom and wiring the TX and RX lines together. I didn't see anything. I've tried a bunch of different speeds with no luck. I'm starting to suspect that the device is powered down, based on this line in init.freescale.rc: write /sys/devices/platform/imx-uart.0/tty/ttymxc0/power/wakeup disabled I did echo enabled > /sys/devices/platform/imx-uart.0/tty/ttymxc0/power/wakeup but that didn't change anything. Anyway, I don't think that anybody can help me out, so this post is just a "marker" in case someone else travels down this path. Cheers all & thanks Booxtor for the information. Warren |
12-01-2015, 02:51 AM | #8 |
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As a followup, I've bought a Bitscope Micro oscilloscope to look at the waveforms on these wires. I am not seeing anything, so perhaps the serial port is not implemented on the T68ML.
Cheers, Warren |
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