Cubieboard2 GPIO help

[Jack Bizon]

Hi everyone,

I need to ask about GPIO pins. I have Cubieboard2 with Armbian (Jessie, Legacy) and I cannot export any GPIO pin as described here http://linux-sunxi.org/GPIO#Accessing_the_GPIO_pins_through_sysfs_with_mainline_kernel, chapter " Accessing the GPIO pins through sysfs with mainline kernel". I was able to play with GPIO this way on Cubian nicely but since Cubian is more or less dead without much support I moved to Armbian. I am able to export only pins with adress 1 or 2 as these are in the script.bin. I quite suspect that I need to change script.fex from GIT, convert to script.bin and replace original one on my Cubieboard. Am I correct? And next thing is that I do not understand what this thingy on sunxi-wiki means: "Device Drivers ---> GPIO Support ---> /sys/class/gpio/... (sysfs interface)" and how to achieve it. Thanks much for help!

[Igor]

This example shows how PH18 is translated to gpio242.

PH18 this would be ( 8 - 1) * 32 + 18 = 224 + 18 = 242 (since 'h' is the 8th letter).
After you have successfully exported the pin you can access it through /sys/class/gpio/gpio*NUMBER* (in case of PH18 it's /sys/class/gpiogpio242).
With /sys/class/gpio/gpio*NUMBER*/direction you can set the pin to out or in using

If you recalculate numbers properly, according to the schema described there, it should work. It's tested / proven unless we broke something in last build. Forget about script.bin in mainline kernel. It's there only that you can easy switch back to old kernel if wanted.

[Jack Bizon]

Thanks for your reply Igor. Well I'm trying PE9 and that gives me (5-1)*32+9=4*32+9=128+9=137, so then I try

 

echo 137 > /sys/class/gpio/export

but that gives me

 

-bash: echo : write error : Invalid argument

If i try with 1 instead of 137 everything is OK. I tried all possible variants of echo, tee, pipelining commands but I still get the invalid argument error on exporting everything else than 1 and 2. I'm not a linux pro, more like newbie, so i guess it's something stupid. And also, I'm connected through serial line console using PL2303. Could that play any role? Thanks for reply.

[tkaiser]

Armbian (Jessie, Legacy [...] chapter " Accessing the GPIO pins through sysfs with mainline kernel".

 

Using 3.4 kernel and trying to follow tutorials for mainline kernel will not work. Try to read from here on http://linux-sunxi.org/GPIO#Accessing_the_GPIO_pins_through_sysfs_on_sunxi-3.4

 

And since you're using Jessie it should work to do a 

apt-get install sunxi-tools

to get the necessary tools. In case you're still stuck it might be a good idea to post the GPIO configuration from script.bin after translated through bin2fex.

[Jack Bizon]

I tought it have to do something with kernel. As I need 3.4 kernel, then I had to modify script.bin. I took script.bin from Cubian and from Armbian, merged gpio_para sections together and voilà... GPIO works nicely on armbian same way as on cubian. I need to do some minor tweaks but I can migrate app to armbian in matter of minutes now. Thanks for your help guys!

[tkaiser]

Would be fine if you post your fex modifications here with comments which changes were necessary because of what. In case your changes are bug fixes or general improvements why not letting us include them in the distro?

[Jack Bizon]

I will be happy to do so! However this is maybe quite specific for cubieboard1/2. I used this Cubian fex https://github.com/mmplayer/sunxi-boards/blob/master/sys_config/a20/cubieboard2_argon.fexand took whole section [gpio_para] and matched it to armbian fex from here https://github.com/igorpecovnik/lib/blob/master/config/cubieboard2.fex. If we take a look onto section [gpio_para] the in armbian there is only this

[gpio_para]
gpio_used = 1
gpio_num                 = 2
gpio_pin_1              = port:PH20<1><default><default><1>
gpio_pin_2              = port:PH21<1><default><default><1>

but in cubian we can see this

[gpio_para]
gpio_used = 1
gpio_num = 67
gpio_pin_1 = port:PG03<1><default><default><1>
gpio_pin_2 = port:PB19<1><default><default><1>
gpio_pin_3 = port:PB18<1><default><default><1>
gpio_pin_4 = port:PG06<1><default><default><1>
gpio_pin_5 = port:PG05<1><default><default><1>
gpio_pin_6 = port:PG04<1><default><default><1>
gpio_pin_7 = port:PG01<1><default><default><1>
gpio_pin_8 = port:PG02<1><default><default><1>
gpio_pin_9 = port:PG00<1><default><default><1>
gpio_pin_10 = port:PH14<1><default><default><1>
gpio_pin_11 = port:PH15<1><default><default><1>
gpio_pin_12 = port:PI06<1><default><default><1>
gpio_pin_13 = port:PI05<1><default><default><1>
gpio_pin_14 = port:PI04<1><default><default><1>
gpio_pin_15 = port:PG11<1><default><default><1>
gpio_pin_16 = port:PG10<1><default><default><1>
gpio_pin_17 = port:PG09<1><default><default><1>
gpio_pin_18 = port:PG08<1><default><default><1>
gpio_pin_19 = port:PG07<1><default><default><1>
gpio_pin_20 = port:PE08<1><default><default><1>
gpio_pin_21 = port:PE07<1><default><default><1>
gpio_pin_22 = port:PE06<1><default><default><1>
gpio_pin_23 = port:PE05<1><default><default><1>
gpio_pin_24 = port:PE04<1><default><default><1>
gpio_pin_25 = port:PI09<1><default><default><1>
gpio_pin_26 = port:PI08<1><default><default><1>
gpio_pin_27 = port:PI07<1><default><default><1>
gpio_pin_28 = port:PD04<1><default><default><1>
gpio_pin_29 = port:PD03<1><default><default><1>
gpio_pin_30 = port:PD02<1><default><default><1>
gpio_pin_31 = port:PD01<1><default><default><1>
gpio_pin_32 = port:PD00<1><default><default><1>
gpio_pin_33 = port:PE11<1><default><default><1>
gpio_pin_34 = port:PE10<1><default><default><1>
gpio_pin_35 = port:PE09<1><default><default><1>
gpio_pin_36 = port:PD12<1><default><default><1>
gpio_pin_37 = port:PD11<1><default><default><1>
gpio_pin_38 = port:PD10<1><default><default><1>
gpio_pin_39 = port:PD09<1><default><default><1>
gpio_pin_40 = port:PD08<1><default><default><1>
gpio_pin_41 = port:PD07<1><default><default><1>
gpio_pin_42 = port:PD06<1><default><default><1>
gpio_pin_43 = port:PD05<1><default><default><1>
gpio_pin_44 = port:PD20<1><default><default><1>
gpio_pin_45 = port:PD19<1><default><default><1>
gpio_pin_46 = port:PD18<1><default><default><1>
gpio_pin_47 = port:PD17<1><default><default><1>
gpio_pin_48 = port:PD16<1><default><default><1>
gpio_pin_49 = port:PD15<1><default><default><1>
gpio_pin_50 = port:PD14<1><default><default><1>
gpio_pin_51 = port:PD13<1><default><default><1>
gpio_pin_52 = port:PB02<1><default><default><1>
gpio_pin_53 = port:PD25<1><default><default><1>
gpio_pin_54 = port:PD24<1><default><default><1>
gpio_pin_55 = port:PD26<1><default><default><1>
gpio_pin_56 = port:PD27<1><default><default><1>
gpio_pin_57 = port:PD23<1><default><default><1>
gpio_pin_58 = port:PD22<1><default><default><1>
gpio_pin_59 = port:PD21<1><default><default><1>
gpio_pin_60 = port:PI11<1><default><default><1>
gpio_pin_61 = port:PI13<1><default><default><1>
gpio_pin_62 = port:PI10<1><default><default><1>
gpio_pin_63 = port:PI12<1><default><default><1>
gpio_pin_64 = port:PB13<1><default><default><1>
gpio_pin_65 = port:PB11<1><default><default><1>
gpio_pin_66 = port:PB10<1><default><default><1>
gpio_pin_67 = port:PH07<1><default><default><1>

On cubieboard there is 67 gpio pins that we can use any way we want. The whole magic was to offset cubian [gpio_para] section by factor of 2 and add it to armbian fex. So the result looks like

[gpio_para]
gpio_used = 1
gpio_num = 69
gpio_pin_1 = port:PH20<1><default><default><1>
gpio_pin_2 = port:PH21<1><default><default><1>
gpio_pin_3 = port:PG03<1><default><default><1>
gpio_pin_4 = port:PB19<1><default><default><1>
gpio_pin_5 = port:PB18<1><default><default><1>
gpio_pin_6 = port:PG06<1><default><default><1>
gpio_pin_7 = port:PG05<1><default><default><1>
gpio_pin_8 = port:PG04<1><default><default><1>
gpio_pin_9 = port:PG01<1><default><default><1>
gpio_pin_10 = port:PG02<1><default><default><1>
gpio_pin_11 = port:PG00<1><default><default><1>
gpio_pin_12 = port:PH14<1><default><default><1>
gpio_pin_13 = port:PH15<1><default><default><1>
gpio_pin_14 = port:PI06<1><default><default><1>
gpio_pin_15 = port:PI05<1><default><default><1>
gpio_pin_16 = port:PI04<1><default><default><1>
gpio_pin_17 = port:PG11<1><default><default><1>
gpio_pin_18 = port:PG10<1><default><default><1>
gpio_pin_19 = port:PG09<1><default><default><1>
gpio_pin_20 = port:PG08<1><default><default><1>
gpio_pin_21 = port:PG07<1><default><default><1>
gpio_pin_22 = port:PE08<1><default><default><1>
gpio_pin_23 = port:PE07<1><default><default><1>
gpio_pin_24 = port:PE06<1><default><default><1>
gpio_pin_25 = port:PE05<1><default><default><1>
gpio_pin_26 = port:PE04<1><default><default><1>
gpio_pin_27 = port:PI09<1><default><default><1>
gpio_pin_28 = port:PI08<1><default><default><1>
gpio_pin_29 = port:PI07<1><default><default><1>
gpio_pin_30 = port:PD04<1><default><default><1>
gpio_pin_31 = port:PD03<1><default><default><1>
gpio_pin_32 = port:PD02<1><default><default><1>
gpio_pin_33 = port:PD01<1><default><default><1>
gpio_pin_34 = port:PD00<1><default><default><1>
gpio_pin_35 = port:PE11<1><default><default><1>
gpio_pin_36 = port:PE10<1><default><default><1>
gpio_pin_37 = port:PE09<1><default><default><1>
gpio_pin_38 = port:PD12<1><default><default><1>
gpio_pin_39 = port:PD11<1><default><default><1>
gpio_pin_40 = port:PD10<1><default><default><1>
gpio_pin_41 = port:PD09<1><default><default><1>
gpio_pin_42 = port:PD08<1><default><default><1>
gpio_pin_43 = port:PD07<1><default><default><1>
gpio_pin_44 = port:PD06<1><default><default><1>
gpio_pin_45 = port:PD05<1><default><default><1>
gpio_pin_46 = port:PD20<1><default><default><1>
gpio_pin_47 = port:PD19<1><default><default><1>
gpio_pin_48 = port:PD18<1><default><default><1>
gpio_pin_49 = port:PD17<1><default><default><1>
gpio_pin_50 = port:PD16<1><default><default><1>
gpio_pin_51 = port:PD15<1><default><default><1>
gpio_pin_52 = port:PD14<1><default><default><1>
gpio_pin_53 = port:PD13<1><default><default><1>
gpio_pin_54 = port:PB02<1><default><default><1>
gpio_pin_55 = port:PD25<1><default><default><1>
gpio_pin_56 = port:PD24<1><default><default><1>
gpio_pin_57 = port:PD26<1><default><default><1>
gpio_pin_58 = port:PD27<1><default><default><1>
gpio_pin_59 = port:PD23<1><default><default><1>
gpio_pin_60 = port:PD22<1><default><default><1>
gpio_pin_61 = port:PD21<1><default><default><1>
gpio_pin_62 = port:PI11<1><default><default><1>
gpio_pin_63 = port:PI13<1><default><default><1>
gpio_pin_64 = port:PI10<1><default><default><1>
gpio_pin_65 = port:PI12<1><default><default><1>
gpio_pin_66 = port:PB13<1><default><default><1>
gpio_pin_67 = port:PB11<1><default><default><1>
gpio_pin_68 = port:PB10<1><default><default><1>
gpio_pin_69 = port:PH07<1><default><default><1>

And this way i got access to GPIO pins on my Cubieboard2. Then it was fun and games to get running my PHP app that provides API for control of GPIO pins over internet via GET requests.

 

As you can see really simple change. I think it would be fine to include change like this in distro but as my understanding goes, armbian is about being universal and this is pretty specific for A10 and A20 boards

[tkaiser]

As you can see really simple change. I think it would be fine to include change like this in distro but as my understanding goes, armbian is about being universal and this is pretty specific for A10 and A20 boards

 

These GPIO settings are board specific so changing it for one board doesn't affect the others. I would prefer to adopt these changes but lack unfortunately both time/resources to try this out (I've a Cubietruck but always used it just as a NAS). It would be great if you could've a look whether Cubieboard 1 and Cubietruck were handled differently in Cubian and report back so we could adopt these changes.

 

It would be also great if you could provide a mini tutorial regarding your PHP <--> GPIO integration!

[Jack Bizon]

Quick comparison of [gpio_para] sections from FEX file in text diff tool and verdict is: Cubieboard1 and Cubieboard2 two are absolutely the same. Cubietruck is almost the same, difference is in just two pins.

gpio_pin_1 = port:PH20<1><default><default><1>
gpio_pin_2 = port:PH10<0><default><default><0>
;gpio_pin_1 = port:PG03<1><default><default><1>
;gpio_pin_2 = port:PB19<1><default><default><1>

This is the difference. PG03 and PB19 are commented and PH20 and PH10 are used instead. Don't know why however, i can't get my hands on cubietruck. All in all my change can be used for Cubie1 and 2 without any problems and for cubietruck.. well you can see it up ^ ^... just two pins.

 

About the tutorial... I'm thinking the same because it is easy to forget. I'll dive into some detailed how-to during this week or upcoming weekend but little spoiler right now.

 

1) start with clean armbian install

2) get apache and php working

3) setup FTP access into /var/www/html for sake of convenience

4) create symlink from /var/www/html/gpio into /sys/class/gpio

5) allow user www-data to read/write in /sys/devices/platform/gpio (chmod -R 777 /sys if you are extremely lazy)

 

Now from /var/www/html PHP scripts should be able to set value on GPIO pins using path gpip/gpio<pin_number>/value . More detailed step by step guide is coming.

[tkaiser]

Thx for the answer. I let the different fex files parse for 'normal' usage of the specific pins and it seems only PB10/PB11 are free to use and all the other pins share functionality and defining them as GPIO pins would break that:

 

 

 

tk@opennms:/var/git/Armbian/lib/config# for fex in cubie*.fex ; do echo -e "\n\n${fex}:\n"; awk -F'<' '{print $1}' /tmp/lala.txt | cut -d':' -f2 | while read ; do OtherUseage="$(grep ${REPLY} $fex  | awk -F" " '{print $1}' | tr "\n" " ")"; echo "${REPLY}: ${OtherUseage}"; done; done


cubieboard2dual.fex:

PG03: csi_vsync sdc_d1 
PB19: twi1_sda 
PB18: twi1_scl 
PG06: csi_d2 
PG05: csi_d1 sdc_d3 
PG04: csi_d0 sdc_d2 
PG01: csi_ck sdc_cmd 
PG02: csi_hsync sdc_d0 
PG00: csi_pck sdc_clk 
PH14: lcdd14 csi_reset csi_reset_b smc_vppen kp_in4 
PH15: lcdd15 smc_vppp kp_in5 audio_pa_ctrl 
PI06: sdc_d0 
PI05: sdc_clk 
PI04: sdc_cmd 
PG11: csi_d7 
PG10: csi_d6 
PG09: csi_d5 
PG08: csi_d4 
PG07: csi_d3 
PE08: csi_d4 
PE07: csi_d3 
PE06: csi_d2 
PE05: csi_d1 
PE04: csi_d0 
PI09: sdc_d3 
PI08: sdc_d2 
PI07: sdc_d1 
PD04: lcdd4 
PD03: lcdd3 
PD02: lcdd2 
PD01: lcdd1 
PD00: lcdd0 
PE11: csi_d7 
PE10: csi_d6 
PE09: csi_d5 
PD12: lcdd12 
PD11: lcdd11 
PD10: lcdd10 
PD09: lcdd9 
PD08: lcdd8 
PD07: lcdd7 
PD06: lcdd6 
PD05: lcdd5 
PD20: lcdd20 
PD19: lcdd19 
PD18: lcdd18 
PD17: lcdd17 
PD16: lcdd16 
PD15: lcdd15 
PD14: lcdd14 
PD13: lcdd13 
PB02: lcd_pwm 
PD25: lcdde 
PD24: lcdclk 
PD26: lcdhsync 
PD27: lcdvsync 
PD23: lcdd23 
PD22: lcdd22 
PD21: lcdd21 
PI11: spi_sclk 
PI13: spi_miso tkey_int compass_int 
PI10: spi_cs0 
PI12: spi_mosi 
PB13: spi_cs1 ctp_wakeup spdif_dout 
PB11: 
PB10: 
PH07: uart_rx lcd_bl_en lcdd7 ms_clk 


cubieboard2.fex:

PG03: csi_vsync sdc_d1 
PB19: twi1_sda 
PB18: twi1_scl 
PG06: csi_d2 
PG05: csi_d1 sdc_d3 
PG04: csi_d0 sdc_d2 
PG01: csi_ck sdc_cmd 
PG02: csi_hsync sdc_d0 
PG00: csi_pck sdc_clk 
PH14: lcdd14 csi_reset csi_reset_b smc_vppen kp_in4 
PH15: lcdd15 smc_vppp kp_in5 audio_pa_ctrl 
PI06: sdc_d0 
PI05: sdc_clk 
PI04: sdc_cmd 
PG11: csi_d7 
PG10: csi_d6 
PG09: csi_d5 
PG08: csi_d4 
PG07: csi_d3 
PE08: csi_d4 
PE07: csi_d3 
PE06: csi_d2 
PE05: csi_d1 
PE04: csi_d0 
PI09: sdc_d3 
PI08: sdc_d2 
PI07: sdc_d1 
PD04: lcdd4 
PD03: lcdd3 
PD02: lcdd2 
PD01: lcdd1 
PD00: lcdd0 
PE11: csi_d7 
PE10: csi_d6 
PE09: csi_d5 
PD12: lcdd12 
PD11: lcdd11 
PD10: lcdd10 
PD09: lcdd9 
PD08: lcdd8 
PD07: lcdd7 
PD06: lcdd6 
PD05: lcdd5 
PD20: lcdd20 
PD19: lcdd19 
PD18: lcdd18 
PD17: lcdd17 
PD16: lcdd16 
PD15: lcdd15 
PD14: lcdd14 
PD13: lcdd13 
PB02: lcd_pwm 
PD25: lcdde 
PD24: lcdclk 
PD26: lcdhsync 
PD27: lcdvsync 
PD23: lcdd23 
PD22: lcdd22 
PD21: lcdd21 
PI11: spi_sclk 
PI13: spi_miso tkey_int compass_int 
PI10: spi_cs0 
PI12: spi_mosi 
PB13: spi_cs1 ctp_wakeup spdif_dout 
PB11: 
PB10: 
PH07: uart_rx lcd_bl_en lcdd7 ms_clk 


cubieboard.fex:

PG03: csi_vsync 
PB19: twi1_sda 
PB18: twi1_scl 
PG06: csi_d2 
PG05: csi_d1 
PG04: csi_d0 
PG01: csi_ck 
PG02: csi_hsync 
PG00: csi_pck 
PH14: lcdd14 csi_reset smc_vppen kp_in4 
PH15: lcdd15 smc_vppp kp_in5 audio_pa_ctrl 
PI06: spi_sclk sdc_d0 
PI05: sdc_clk 
PI04: sdc_cmd 
PG11: csi_d7 
PG10: csi_d6 
PG09: csi_d5 
PG08: csi_d4 
PG07: csi_d3 
PE08: csi_d4 
PE07: csi_d3 
PE06: csi_d2 
PE05: csi_d1 
PE04: csi_d0 
PI09: sdc_d3 
PI08: spi_miso sdc_d2 
PI07: spi_mosi sdc_d1 
PD04: lcdd4 
PD03: lcdd3 
PD02: lcdd2 
PD01: lcdd1 
PD00: lcdd0 
PE11: csi_d7 
PE10: csi_d6 
PE09: csi_d5 
PD12: lcdd12 
PD11: lcdd11 
PD10: lcdd10 
PD09: lcdd9 
PD08: lcdd8 
PD07: lcdd7 
PD06: lcdd6 
PD05: lcdd5 
PD20: lcdd20 
PD19: lcdd19 
PD18: lcdd18 
PD17: lcdd17 
PD16: lcdd16 
PD15: lcdd15 
PD14: lcdd14 
PD13: lcdd13 
PB02: lcd_pwm 
PD25: lcdde 
PD24: lcdclk 
PD26: lcdhsync 
PD27: lcdvsync 
PD23: lcdd23 
PD22: lcdd22 
PD21: lcdd21 
PI11: spi_sclk 
PI13: spi_miso tkey_int compass_int 
PI10: spi_cs0 gsensor_int2 
PI12: spi_mosi tv_en 
PB13: ctp_wakeup spdif_dout 
PB11: 
PB10: 
PH07: uart_rx lcd_bl_en lcdd7 ms_clk 


cubietruck.fex:

PG03: csi_vsync sdc_d1 
PB19: twi1_sda 
PB18: twi1_scl 
PG06: csi_d2 
PG05: csi_d1 sdc_d3 
PG04: csi_d0 sdc_d2 
PG01: csi_ck sdc_cmd 
PG02: csi_hsync sdc_d0 
PG00: csi_pck sdc_clk 
PH14: lcdd14 csi_reset csi_reset_b smc_vppen kp_in4 
PH15: lcdd15 smc_vppp kp_in5 audio_pa_ctrl 
PI06: sdc_d0 
PI05: sdc_clk 
PI04: sdc_cmd 
PG11: csi_d7 
PG10: csi_d6 
PG09: csi_d5 
PG08: csi_d4 
PG07: csi_d3 
PE08: csi_d4 
PE07: csi_d3 
PE06: csi_d2 
PE05: csi_d1 
PE04: csi_d0 
PI09: sdc_d3 
PI08: sdc_d2 
PI07: sdc_d1 
PD04: lcdd4 
PD03: lcdd3 
PD02: lcdd2 
PD01: lcdd1 
PD00: lcdd0 
PE11: csi_d7 
PE10: csi_d6 
PE09: csi_d5 
PD12: lcdd12 
PD11: lcdd11 
PD10: lcdd10 
PD09: lcdd9 
PD08: lcdd8 
PD07: lcdd7 
PD06: lcdd6 
PD05: lcdd5 
PD20: lcdd20 
PD19: lcdd19 
PD18: lcdd18 
PD17: lcdd17 
PD16: lcdd16 
PD15: lcdd15 
PD14: lcdd14 
PD13: lcdd13 
PB02: lcd_pwm 
PD25: lcdde 
PD24: lcdclk 
PD26: lcdhsync 
PD27: lcdvsync 
PD23: lcdd23 
PD22: lcdd22 
PD21: lcdd21 
PI11: spi_sclk 
PI13: spi_miso tkey_int compass_int 
PI10: spi_cs0 
PI12: spi_mosi ap6xxx_lpo 
PB13: spi_cs1 ctp_wakeup spdif_dout 
PB11: 
PB10: 
PH07: uart_rx leds_pin_4 lcd_bl_en lcdd7 ms_clk  

 

 

 

But according to http://linux-sunxi.org/Cubieboard/ExpansionPortsthe two aforementioned pins are also used for LCD. Therefore adopting Cubian's settings might break things for our users. Would be great if you could add the link and these informations to your tutorial since it might help other users to decide which pins they use for GPIO experiments.