# GPIO 7 Problems **URL:** \ **Category:** mangOH Red\ **Created:** [February 15, 2021, 9:16am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171 "2021-02-15T09:16:08Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [February 15, 2021, 9:16am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/1 "2021-02-15T09:16:08Z")
WP7702 GPIO 7 (Mangoh Red IOT0\_GPIO3, pin 26) will not respond to the le\_gpio commands issued to it. legato programs will bind properly and silently accept all issued commands, but it will not change value or pull-up/pull-down. Interestingly I can apparently change the input/output state and the pull-up/pull-down state from the command line, but the changes have no effect. ``` cat /sys/kernel/debug/gpio GPIOs 0-79, platform/1000000.pinctrl, 1000000.pinctrl: gpio0 : in 0 2mA pull down gpio1 : in 0 2mA pull down gpio2 : in 0 2mA pull up gpio3 : in 0 2mA pull down gpio4 : out 2 2mA pull up gpio5 : in 2 2mA pull down gpio6 : in 2 2mA pull down gpio7 : out 2 2mA pull up gpio8 : in 0 2mA no pull gpio9 : in 0 2mA no pull gpio10 : in 0 2mA no pull gpio11 : in 0 2mA no pull gpio12 : out 2 2mA pull down gpio13 : in 2 2mA pull down gpio14 : in 2 2mA no pull gpio15 : in 2 2mA no pull gpio16 : out 0 2mA pull up gpio17 : in 0 2mA pull up gpio18 : in 0 2mA pull down gpio19 : in 0 2mA pull down gpio20 : out 3 8mA no pull gpio21 : in 3 8mA no pull gpio22 : out 3 8mA no pull gpio23 : out 3 8mA no pull gpio24 : out 0 2mA no pull gpio25 : out 0 6mA no pull gpio26 : in 0 2mA pull up gpio27 : out 0 2mA no pull gpio28 : out 0 2mA no pull gpio29 : out 0 2mA no pull gpio30 : in 1 2mA pull up gpio31 : out 1 2mA no pull gpio32 : out 1 2mA no pull gpio33 : out 1 2mA no pull gpio34 : in 1 2mA pull up gpio35 : in 0 2mA pull down gpio36 : out 0 2mA no pull gpio37 : in 0 2mA no pull gpio38 : in 0 2mA no pull gpio39 : out 1 2mA pull down gpio40 : out 1 2mA pull down gpio41 : out 1 2mA pull down gpio42 : out 1 2mA pull down gpio43 : out 1 2mA pull down gpio44 : out 1 2mA pull down gpio45 : in 0 2mA no pull gpio46 : in 0 2mA no pull gpio47 : in 0 2mA no pull gpio48 : in 0 2mA no pull gpio49 : out 1 2mA pull down gpio50 : out 1 2mA pull down gpio51 : in 0 2mA no pull gpio52 : out 1 2mA pull down gpio53 : out 3 2mA pull down gpio54 : out 0 6mA no pull gpio55 : out 1 2mA no pull gpio56 : out 1 2mA pull down gpio57 : out 1 2mA pull down gpio58 : out 0 2mA no pull gpio59 : in 0 2mA pull up gpio60 : in 0 2mA pull down gpio61 : in 0 2mA pull down gpio62 : in 0 2mA pull down gpio63 : in 0 2mA pull down gpio64 : in 0 2mA pull down gpio65 : in 0 2mA pull down gpio66 : in 0 2mA pull down gpio67 : in 0 2mA pull down gpio68 : in 0 2mA pull down gpio69 : in 0 2mA pull down gpio70 : in 0 2mA pull down gpio71 : in 0 2mA pull down gpio72 : in 0 2mA pull down gpio73 : in 0 2mA pull down gpio74 : in 0 2mA pull down gpio75 : out 0 6mA no pull gpio76 : out 0 2mA no pull gpio77 : in 0 2mA no pull gpio78 : in 0 2mA no pull gpio79 : in 0 2mA no pull GPIOs 200-204, platform/swimcu-gpio, swimcu, can sleep: GPIOs 820-851, platform/soc:qcom,smp2pgpio-ssr-smp2p-1-out, master-kernel: GPIOs 852-883, platform/soc:qcom,smp2pgpio-ssr-smp2p-1-in, slave-kernel: GPIOs 884-915, platform/soc:qcom,smp2pgpio-smp2p-1-out, smp2p: GPIOs 916-947, platform/soc:qcom,smp2pgpio-smp2p-1-in, smp2p: GPIOs 948-979, platform/soc:qcom,smp2pgpio-smp2p-15-out, smp2p: GPIOs 980-1011, platform/soc:qcom,smp2pgpio-smp2p-15-in, smp2p: GPIOs 1012-1017, spmi/qpnp-pin-7, pm8019-mpp: gpio-1012 (USB_ID_GPIO ) in hi GPIOs 1018-1023, spmi/qpnp-pin-6, pm8019-gpio: gpio-1023 (sfpr-gpio ) in lo echo 1 > /sys/class/gpio/gpio7/value; cat /sys/class/gpio/gpio7/value 0 ``` I can even unexport and export gpio7 to no effect. It will not write the pin high, and will still silently accept any commands issued to it. I can also use AT commands to check if the GPIO is supposed to be attached to the linux processor or not, and the problem is still present there. I can configure it as a GPIO output under the AT command section with AT+WIOCFG=7,4,1,0,1,0,0 and it will respond OK to AT+WIOW=7,1 but the output is still low. Anyone else seen this? I haven’t come across any other documentation indicating GPIO7 is disabled or unavailable. ---
**Author:** ![jyijyi](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/jyijyi/32/997_2.png) [@jyijyi](https://mangoh.discourse.group/u/jyijyi)\ **Post date:** [February 15, 2021, 12:43pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/2 "2021-02-15T12:43:52Z")
I don’t see problem on controlling GPIO7 on WP7702 on mangoh red board. I can see the voltage is changed: echo 7 \> /sys/class/gpio/export echo out \> /sys/class/gpio/gpio7/direction echo 0 \> /sys/class/gpio/gpio7/value echo 1 \> /sys/class/gpio/gpio7/value ati3 Manufacturer: Sierra Wireless, Incorporated Model: WP7702 Revision: SWI9X06Y\_02.22.12.00 eaf79c jenkins 2019/04/24 18:48:27 IMEI: 352653090002874 IMEI SV: 3 FSN: VU735370521401 +GCAP: +CGSM OK [37.337537] i2c-msm-v2 78b8000.i2c: NACK: slave not responding, ensure its powered: msgs(n:1 cur:0 tx) bc(rx:0 tx:2) mode:FIFO slv\_addr:0x3a MSTR\_STS:0x0c1300c8 OPER:0x00000090 Legato Ver: 18.09.4.c964f253\_3ba44b6732e03bacfafb714c4463754d Yocto Ver: SWI9X06Y\_02.22.04.00 2020-06-18\_02:43:58 OS Ver: Linux version 3.18.44 (jenkins@CAKEL-EV-ALBLD2) (gcc version 6.2.0 (GCC) ) #2 PREEMPT Thu Jun 18 02:45:08 UTC 2020 LK Ver: 1.3.0\_da731a7332 RootFS Ver: SWI9X06Y\_02.22.04.00 2020-06-18\_02:43:58 UserFS Ver: unknown MCU Ver: 002.011 OK I am measuring on here: ![image](https://us1.discourse-cdn.com/flex016/uploads/mangoh/original/2X/1/13ee39ed570a71afb115d2f26fc9a1995a88724f.jpeg) ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [February 15, 2021, 5:20pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/3 "2021-02-15T17:20:37Z")
I followed the above commands and could not detect any change on my scope. Measured as indicated on the PCB, and soldered into pin 26 of the IoT connector. ``` root@swi-mdm9x28-wp:~# echo 7 > /sys/class/gpio/export root@swi-mdm9x28-wp:~# echo out > /sys/class/gpio/gpio7/direction root@swi-mdm9x28-wp:~# echo 0 > /sys/class/gpio/gpio7/value root@swi-mdm9x28-wp:~# echo 1 > /sys/class/gpio/gpio7/value root@swi-mdm9x28-wp:~# cat /sys/class/gpio/gpio7/value 0 root@swi-mdm9x28-wp:~# microcom /dev/ttyAT ati3 Manufacturer: Sierra Wireless, Incorporated Model: WP7702 Revision: SWI9X06Y_02.16.06.00 7605a6 jenkins 2018/06/20 17:56:12 IMEI: 3526xxxx IMEI SV: 2 FSN: VU74xxx +GCAP: +CGSM ``` Just to double check I used swiflash to instal the latest spk I could find from Sierra wireless and It’s still on IMEI SV:2. How do I get to your revision? ---
**Author:** ![jyijyi](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/jyijyi/32/997_2.png) [@jyijyi](https://mangoh.discourse.group/u/jyijyi)\ **Post date:** [February 15, 2021, 11:45pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/4 "2021-02-15T23:45:57Z")
I am using fx30 (WP77 module inside) fw which is fw r11. FYI, i also tried on wp76 module with same mangoh red board, no problem is found on gpio7. Not sure if you are really measuring the correct pin on the board, maybe you can measure the same point as my indication above. ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [February 16, 2021, 2:50pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/5 "2021-02-16T14:50:04Z")
These are the documentation I’ve been referencing. > **[MangoRed\_DV6\_final.pdf](https://mangoh.io/uploaded-documents/Reference/mangOH%20Red/Hardware/Schematics/MangoRed_DV6_final.pdf)** > > 1609.24 KB [https://source.sierrawireless.com/resources/airprime/hardware\_specs\_user\_guides/airprime\_wp77xx\_product\_technical\_specification/#sthash.pfxN6N27.dpbs](https://source.sierrawireless.com/resources/airprime/hardware_specs_user_guides/airprime_wp77xx_product_technical_specification/#sthash.pfxN6N27.dpbs) First point: In the Technical specifications GPIO7 is listed as pin 40. In the schematic, Page 2, section C-3 indicated pin 40 is indeed gpio7. In the same schematic, Page 3, section H-3, says the pin is connected to CN306 Pin 26. In the same schematic, Page 4, section I-8, says the pin is also connected to CN401 Pin 4, or the unpopulated surface mount header you illustrated. I made measurements of both points, neither produced any change. If you still think I’m not measuring the right point I’ll send you picture of the scope leads connected to the board next week when I’m back in the office. Second point: Even if I was measuring the wrong pin, I am very suspicious of the fact that I can’t write to the pin. If I cat the value immediately after writing it high, and the pin is already low. I think there’s a service/program/driver somewhere forcing the pin low. Why else would the pin ignore any output commands from the linux system, and from the AT system? The pin is never driven high, and **that’s verifiable with the oscilloscope**. The unpopulated connector you mentioned on page 4 section I-7 of the schematic shows GPIO7 is used for SWD\_CLK. The product spec makes no mention of SWD, nor does the legato docs. Could SWD be messing with this? I have no idea what else this could be. ---
**Author:** ![jyijyi](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/jyijyi/32/997_2.png) [@jyijyi](https://mangoh.discourse.group/u/jyijyi)\ **Post date:** [February 16, 2021, 3:00pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/6 "2021-02-16T15:00:44Z")
In the same schematic, Page 3, section H-3, says the pin is connected to CN306 Pin 26. In the same schematic, Page 4, section I-8, says the pin is also connected to CN401 Pin 4, or the unpopulated surface mount header you illustrated. You can double check by using multimeter and see if those two points are actually the same point. ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [February 16, 2021, 3:57pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/7 "2021-02-16T15:57:12Z")
You seem to be very focused on thinking that I can’t measure the voltage of a pin properly. **I probed both points.** Did you read my second point about the value of the pin not changing? Assume for a second that I can operate an oscilloscope and a multimeter, what would be the next thing you check? Why would the value of gpio7 not respond to a write by the root user? ---
**Author:** ![jyijyi](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/jyijyi/32/997_2.png) [@jyijyi](https://mangoh.discourse.group/u/jyijyi)\ **Post date:** [February 16, 2021, 4:02pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/8 "2021-02-16T16:02:23Z")
i don’t see anything else i can check then as I cannot see the problem. ( and that is why I suspect you are not measuring the correct point) Maybe you can try the same FW as mine. [https://source.sierrawireless.com/resources/airlink/software\_downloads/fx30-firmware/fx30-firmware-catm/#sthash.Ub3J4uTS.dpbs](https://source.sierrawireless.com/resources/airlink/software_downloads/fx30-firmware/fx30-firmware-catm/#sthash.Ub3J4uTS.dpbs) Another possibility is that your metal case of WP77 is not closed well… ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [February 22, 2021, 7:40am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/9 "2021-02-22T07:40:03Z")
Back in the lab today. I tested the mangoh red PCB with WP module removed. Pin 40 has continuity to both the pin indicated in your drawing and IOT3 connector pin 26. Will FX30 firmware work on mangoh red boards? Anything I should be aware of? ---
**Author:** ![jyijyi](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/jyijyi/32/997_2.png) [@jyijyi](https://mangoh.discourse.group/u/jyijyi)\ **Post date:** [February 22, 2021, 7:48am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/10 "2021-02-22T07:48:58Z")
i already use the FX30 FW on mangoh red board to test GPIO7. ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [February 22, 2021, 8:21am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/11 "2021-02-22T08:21:28Z")
Under FX30 firmware the board reports an error rather than silently accepting it. It’s a step in the right direction. ``` root@fx30:~# echo 1 > /sys/class/gpio/gpio7/value sh: write error: Operation not permitted ``` I have also unexported and re-exported the gpio, to no effect. ``` root@fx30:~# cat /sys/kernel/debug/gpio GPIOs 0-79, platform/1000000.pinctrl, 1000000.pinctrl: gpio0 : in 0 2mA pull down gpio1 : in 0 2mA pull down gpio2 : in 0 2mA pull up gpio3 : in 0 2mA pull down gpio4 : out 2 2mA pull up gpio5 : in 2 2mA pull down gpio6 : in 2 2mA pull down gpio7 : out 2 2mA pull up gpio8 : in 0 2mA pull up gpio9 : in 0 2mA pull up gpio10 : out 0 16mA pull down gpio11 : in 0 2mA pull up gpio12 : out 2 2mA pull down gpio13 : in 2 2mA pull down gpio14 : in 2 2mA pull down gpio15 : in 2 2mA pull down gpio16 : in 0 2mA pull up gpio17 : in 0 2mA pull up gpio18 : in 0 2mA pull down gpio19 : in 0 2mA pull down gpio20 : out 3 8mA no pull gpio21 : in 3 8mA no pull gpio22 : out 3 8mA no pull gpio23 : out 3 8mA no pull gpio24 : out 0 2mA no pull gpio25 : out 0 6mA no pull gpio26 : in 0 2mA pull up gpio27 : out 0 2mA no pull gpio28 : out 0 2mA no pull gpio29 : out 0 2mA no pull gpio30 : in 1 2mA pull up gpio31 : out 1 2mA no pull gpio32 : out 1 2mA no pull gpio33 : out 1 2mA no pull gpio34 : in 1 2mA pull up gpio35 : in 0 2mA pull down gpio36 : out 0 2mA no pull gpio37 : in 0 2mA no pull gpio38 : in 0 2mA pull up gpio39 : in 0 2mA pull down gpio40 : in 0 2mA pull down gpio41 : in 0 2mA pull down gpio42 : in 0 2mA pull down gpio43 : in 0 2mA pull down gpio44 : in 0 2mA pull down gpio45 : in 0 2mA no pull gpio46 : out 0 2mA no pull gpio47 : in 0 2mA no pull gpio48 : in 0 2mA no pull gpio49 : in 0 2mA pull down gpio50 : in 0 2mA pull down gpio51 : in 0 2mA pull up gpio52 : in 0 2mA pull up gpio53 : in 3 2mA pull down gpio54 : out 0 6mA no pull gpio55 : out 0 2mA no pull gpio56 : in 0 2mA no pull gpio57 : out 0 2mA no pull gpio58 : in 0 2mA no pull gpio59 : in 0 2mA pull up gpio60 : in 0 2mA pull down gpio61 : in 0 2mA pull down gpio62 : in 0 2mA pull down gpio63 : in 0 2mA pull down gpio64 : in 0 2mA pull down gpio65 : in 0 2mA pull down gpio66 : in 0 2mA pull down gpio67 : in 0 2mA pull down gpio68 : in 0 2mA pull down gpio69 : in 0 2mA pull down gpio70 : in 0 2mA pull down gpio71 : in 0 2mA pull down gpio72 : in 0 2mA pull down gpio73 : in 0 2mA pull down gpio74 : in 0 2mA pull down gpio75 : out 0 6mA no pull gpio76 : in 0 2mA no pull gpio77 : out 0 2mA no pull gpio78 : in 0 2mA no pull gpio79 : in 0 2mA no pull GPIOs 200-204, platform/swimcu-gpio, swimcu, can sleep: gpio-200 (sysfs ) in hi gpio-202 (sysfs ) in hi GPIOs 820-851, platform/soc:qcom,smp2pgpio-ssr-smp2p-1-out, master-kernel: GPIOs 852-883, platform/soc:qcom,smp2pgpio-ssr-smp2p-1-in, slave-kernel: GPIOs 884-915, platform/soc:qcom,smp2pgpio-smp2p-1-out, smp2p: GPIOs 916-947, platform/soc:qcom,smp2pgpio-smp2p-1-in, smp2p: GPIOs 948-979, platform/soc:qcom,smp2pgpio-smp2p-15-out, smp2p: GPIOs 980-1011, platform/soc:qcom,smp2pgpio-smp2p-15-in, smp2p: gpio-996 (sysfs ) in hi gpio-997 (sysfs ) in hi gpio-998 (sysfs ) in hi gpio-999 (sysfs ) in hi gpio-1000 (sysfs ) in hi gpio-1001 (sysfs ) in hi gpio-1002 (sysfs ) in hi gpio-1003 (sysfs ) in hi gpio-1004 (sysfs ) in hi gpio-1005 (sysfs ) in hi gpio-1006 (sysfs ) in hi gpio-1007 (sysfs ) in hi gpio-1008 (sysfs ) in hi gpio-1009 (sysfs ) in hi gpio-1010 (sysfs ) in hi gpio-1011 (sysfs ) in hi GPIOs 1012-1017, spmi/qpnp-pin-7, pm8019-mpp: gpio-1012 (USB_ID_GPIO ) in hi GPIOs 1018-1023, spmi/qpnp-pin-6, pm8019-gpio: gpio-1023 (sfpr-gpio ) in lo root@fx30:~# ``` ---
**Author:** ![jyijyi](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/jyijyi/32/997_2.png) [@jyijyi](https://mangoh.discourse.group/u/jyijyi)\ **Post date:** [February 22, 2021, 8:45am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/12 "2021-02-22T08:45:51Z")
do you set it to output? It seems it is still set as input. ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [February 22, 2021, 3:40pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/13 "2021-02-22T15:40:26Z")
Set as output now. It’s back to ignoring any errors and not setting the value as directed. ``` root@fx30:~# cat /sys/class/gpio/gpio7/direction in root@fx30:~# echo out > /sys/class/gpio/gpio7/direction root@fx30:~# echo 1 > /sys/class/gpio/gpio7/value root@fx30:~# cat /sys/class/gpio/gpio7/value 0 ``` ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [February 22, 2021, 9:52pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/14 "2021-02-22T21:52:28Z")
I ordered new WP7702 modules to test with. If that doesn’t fix it then the mangoh red board will be my next replaced item. ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [March 8, 2021, 8:30pm UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/15 "2021-03-08T20:30:12Z")
@jyijyi 5 new WP7702 modules later, and no change, so it wasn’t ESD. I decided to do measure a couple things with the module removed, turns out there’s a low impedance path to ground from the pin you indicated. This tells me either my mangoh red PCB is damaged in some way, or my PCB is different from yours. Were there different revisions of the PCB? ---
**Author:** ![jyijyi](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/jyijyi/32/997_2.png) [@jyijyi](https://mangoh.discourse.group/u/jyijyi)\ **Post date:** [March 9, 2021, 1:10am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/16 "2021-03-09T01:10:27Z")
on my mangoh red board, it says “REV5.0” ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [March 9, 2021, 6:00am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/17 "2021-03-09T06:00:34Z")
I also have revision 5.0 ---
**Author:** ![jyijyi](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/jyijyi/32/997_2.png) [@jyijyi](https://mangoh.discourse.group/u/jyijyi)\ **Post date:** [March 9, 2021, 6:07am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/18 "2021-03-09T06:07:21Z")
do you mean CN306 Pin 26 or CN401 Pin 4 are actually ground? ---
**Author:** ![CT1](https://avatars.discourse-cdn.com/v4/letter/c/f6c823/32.png) [@CT1](https://mangoh.discourse.group/u/CT1)\ **Post date:** [March 9, 2021, 6:24am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/19 "2021-03-09T06:24:18Z")
They’re both ground. To be explicitly clear… With the module removed CN306 Pin 26, CN401 Pin 4, J200 Pin 40 and GND are all connected. ---
**Author:** ![jyijyi](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/jyijyi/32/997_2.png) [@jyijyi](https://mangoh.discourse.group/u/jyijyi)\ **Post date:** [March 9, 2021, 6:30am UTC](https://mangoh.discourse.group/t/gpio-7-problems/6171/20 "2021-03-09T06:30:54Z")
strange, isn’t this violate the schematic??? [Next page](https://mangoh.discourse.group/t/gpio-7-problems/6171.md?page=2)