Jetson Nano Developer Kit 40-Pin Expansion Header Configuration problem

Robotics & Edge Computing Jetson & Embedded Systems Jetson Nano
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1

Hello. I’m using Jetson Nano 2GB, model P3541 with JetPack 4.6 (L4T 32.6.1).

I need to change some default settings for some pins, e.g. to disable Pull-Up/Pull-Down at startup. What I’ve done following the documentation:

  1. In the pinmux table, I changed the value of the column " Req. Initial State " (col. AU) and set it as " Drive 0 ". By the way, I tried all the values from the list except for " Input PD/PU ". I didn’t make any other changes.

  2. I generated two DTSI files (by pressing on the button “Generate DT File”) and copied them to the folder Linux_for_Tegra/source/public/hardware/nvidia/platform/t210/batuu/kernel-dts/batuu-platforms/ : tegra210-batuu-gpio-p3448-0003.dtsi and tegra210-batuu-pinmux-p3448-0003.dtsi accordinly.

  3. I successfully compiled a new DTB file by the commands: make ARCH=arm64 tegra_defconfig and make ARCH=arm64 dtbs and didn’t forget to set CROSS_COMPILE variable before doing that (export CROSS_COMPILE=…).

  4. I took the new file tegra210-p3448-0003-p3542-0000.dtb from the folder Linux_for_Tegra/source/public/kernel/kernel-4.9/arch/arm64/boot/dts/ and put it to the folder Linux_for_Tegra/kernel/dtb/.

  5. Then, I successfully flashed my Jetson Nano by the command: sudo ./flash.sh -k DTB jetson-nano-2gb-devkit mmcblk0p1 .

But, after restarting, I saw no changes. The pins, which I expected to see with the disabled Pull-Down state, have remained in that state (I’m watching them on an oscilloscope).

Could someone to explain what I did wrong or how to do it right? Any suggestions, please.

3

hello alexey.mihaylov,

could you please also review # cat /sys/kernel/debug/gpio for the pin configurations.
thanks

4

gpiochip0: GPIOs 0-255, parent: platform/6000d000.gpio, tegra-gpio:
gpio-0 ( )
gpio-1 ( )
gpio-2 ( |pcie_wake ) in hi
gpio-3 ( )
gpio-4 ( )
gpio-5 ( )
gpio-6 ( |system-suspend-gpio ) out hi
gpio-7 ( )
gpio-8 ( )
gpio-9 ( )
gpio-10 ( )
gpio-11 ( )
gpio-12 (SPI1_MOSI )
gpio-13 (SPI1_MISO )
gpio-14 (SPI1_SCK )
gpio-15 (SPI1_CS0 )
gpio-16 (SPI0_MOSI )
gpio-17 (SPI0_MISO )
gpio-18 (SPI0_SCK )
gpio-19 (SPI0_CS0 )
gpio-20 (SPI0_CS1 )
gpio-21 ( )
gpio-22 ( )
gpio-23 ( )
gpio-24 ( )
gpio-25 ( )
gpio-26 ( )
gpio-27 ( )
gpio-28 ( )
gpio-29 ( )
gpio-30 ( )
gpio-31 ( )
gpio-32 ( )
gpio-33 ( )
gpio-34 ( )
gpio-35 ( )
gpio-36 ( )
gpio-37 ( )
gpio-38 (GPIO13 )
gpio-39 ( )
gpio-40 ( )
gpio-41 ( )
gpio-42 ( )
gpio-43 ( )
gpio-44 ( )
gpio-45 ( )
gpio-46 ( )
gpio-47 ( )
gpio-48 ( )
gpio-49 ( )
gpio-50 (UART1_RTS )
gpio-51 (UART1_CTS )
gpio-52 ( )
gpio-53 ( )
gpio-54 ( )
gpio-55 ( )
gpio-56 ( )
gpio-57 ( )
gpio-58 ( )
gpio-59 ( )
gpio-60 ( )
gpio-61 ( )
gpio-62 ( )
gpio-63 ( )
gpio-64 ( )
gpio-65 ( |? ) out hi
gpio-66 ( |vdd-usb-vbus-en ) out hi
gpio-67 ( )
gpio-68 ( )
gpio-69 ( )
gpio-70 ( )
gpio-71 ( )
gpio-72 ( )
gpio-73 ( )
gpio-74 ( )
gpio-75 ( )
gpio-76 (I2S0_FS )
gpio-77 (I2S0_DIN )
gpio-78 (I2S0_DOUT )
gpio-79 (I2S0_SCLK )
gpio-80 ( )
gpio-81 ( )
gpio-82 ( )
gpio-83 ( )
gpio-84 ( )
gpio-85 ( )
gpio-86 ( )
gpio-87 ( )
gpio-88 ( )
gpio-89 ( )
gpio-90 ( )
gpio-91 ( )
gpio-92 ( )
gpio-93 ( )
gpio-94 ( )
gpio-95 ( )
gpio-96 ( )
gpio-97 ( )
gpio-98 ( )
gpio-99 ( )
gpio-100 ( )
gpio-101 ( )
gpio-102 ( )
gpio-103 ( )
gpio-104 ( )
gpio-105 ( )
gpio-106 ( )
gpio-107 ( )
gpio-108 ( )
gpio-109 ( )
gpio-110 ( )
gpio-111 ( )
gpio-112 ( )
gpio-113 ( )
gpio-114 ( )
gpio-115 ( )
gpio-116 ( )
gpio-117 ( )
gpio-118 ( )
gpio-119 ( )
gpio-120 ( )
gpio-121 ( )
gpio-122 ( )
gpio-123 ( )
gpio-124 ( )
gpio-125 ( )
gpio-126 ( )
gpio-127 ( )
gpio-128 ( )
gpio-129 ( )
gpio-130 ( )
gpio-131 ( )
gpio-132 ( )
gpio-133 ( )
gpio-134 ( )
gpio-135 ( )
gpio-136 ( )
gpio-137 ( )
gpio-138 ( )
gpio-139 ( )
gpio-140 ( )
gpio-141 ( )
gpio-142 ( )
gpio-143 ( )
gpio-144 ( )
gpio-145 ( )
gpio-146 ( )
gpio-147 ( )
gpio-148 ( )
gpio-149 (GPIO01 )
gpio-150 ( )
gpio-151 ( )
gpio-152 ( )
gpio-153 ( )
gpio-154 ( )
gpio-155 ( )
gpio-156 ( )
gpio-157 ( )
gpio-158 ( )
gpio-159 ( )
gpio-160 ( )
gpio-161 ( )
gpio-162 ( )
gpio-163 ( )
gpio-164 ( )
gpio-165 ( )
gpio-166 ( )
gpio-167 ( )
gpio-168 (GPIO07 )
gpio-169 ( )
gpio-170 ( )
gpio-171 ( )
gpio-172 ( )
gpio-173 ( )
gpio-174 ( )
gpio-175 ( )
gpio-176 ( )
gpio-177 ( )
gpio-178 ( )
gpio-179 ( )
gpio-180 ( )
gpio-181 ( )
gpio-182 ( )
gpio-183 ( )
gpio-184 ( )
gpio-185 ( )
gpio-186 ( )
gpio-187 ( )
gpio-188 ( )
gpio-189 ( |Power ) in hi IRQ
gpio-190 ( |Forcerecovery ) in hi IRQ
gpio-191 ( )
gpio-192 ( )
gpio-193 ( )
gpio-194 (GPIO12 )
gpio-195 ( )
gpio-196 ( )
gpio-197 ( )
gpio-198 ( )
gpio-199 ( )
gpio-200 (GPIO11 )
gpio-201 ( |cd ) in lo IRQ
gpio-202 ( |pwm-fan-tach ) in hi IRQ
gpio-203 ( |vdd-3v3-sd ) out hi
gpio-204 ( )
gpio-205 ( )
gpio-206 ( )
gpio-207 ( )
gpio-208 ( )
gpio-209 ( )
gpio-210 ( )
gpio-211 ( )
gpio-212 ( )
gpio-213 ( )
gpio-214 ( )
gpio-215 ( )
gpio-216 (GPIO09 )
gpio-217 ( )
gpio-218 ( )
gpio-219 ( )
gpio-220 ( )
gpio-221 ( )
gpio-222 ( )
gpio-223 ( )
gpio-224 ( )
gpio-225 ( |hdmi2.0_hpd ) in lo IRQ
gpio-226 ( )
gpio-227 ( )
gpio-228 ( |extcon:extcon@1 ) in lo IRQ
gpio-229 ( )
gpio-230 ( )
gpio-231 ( |? ) out hi
gpio-232 (SPI1_CS1 )
gpio-233 ( )
gpio-234 ( )
gpio-235 ( )
gpio-236 ( )
gpio-237 ( )
gpio-238 ( )
gpio-239 ( )

gpiochip1: GPIOs 504-511, parent: platform/max77620-gpio, max77620-gpio, can sleep:
gpio-505 ( |spmic-default-output) out hi
gpio-507 ( |vdd-3v3-sys ) out hi
gpio-510 ( |enable ) out hi
gpio-511 ( |avdd-io-edp-1v05 ) out lo

5

hello alexey.mihaylov,

may I know which GPIO pin you’ve configured, did sysnode shows the same settings?

6

Hello Jerry,
I’m trying to configure all of these ones: gpio- 12, 13, 14, 15, 16, 17, 18, 19, 20, 38, 50, 51, 76, 77, 78, 79, 149, 168, 194, 200, 216, 232. Actually, I need one pin only but I’m trying all the possible…

Due to macros I cannot upload my XLSM file but you can have a look at dtsi files:
tegra210-jetson_nano_2gb_module-gpio-default.dtsi (2.1 KB)
tegra210-jetson_nano_2gb_module-pinmux.dtsi (38.1 KB)

7

I saved the spreadsheet without macros and now can upload it.
jetson-nano-2gb-devkit_pinmux.xlsx (189.9 KB)

8

hello alexey.mihaylov,

it’s device tree, i.e. tegra210-jetson_nano_2gb_module-pinmux.dtsi, to assign the settings,
please access Applications Note for 40-Pin Expansion Header GPIO Usage Considerations.
you may also refer to [“Keeper” Pull-up and Pull-down Resistors] by checking the pin via an oscilloscope,
thanks

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