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en:bpi-r2:gpio

GPIO

Basics

Pin define

image taken from bpi-r2 schematics

Sparefunction Mainfunction pin# xxxxxxxxxxxxxxxxxxxxx pin# Mainfunction Sparefunction
- 3V3 1 2 5V -
I2C_SDA0 GPIO 75 3 4 5V -
I2C SCL0 GPIO 76 5 6 GND -
PWM3 GPIO 206 7 8 GPIO 82 UART1 TX
- GND 9 10 GPIO 81 UART1 RX
UART0 TX GPIO 80 11 12 UCTS1 / INT2 GPIO 24 (*)
UART0 RX GPIO 79 13 14 GND -
PWM2 GPIO 205 15 16 GPIO 25 / INT3 URTS1
- 3V3 17 18 GPIO 21 PCM_TX
SPI0_MO GPIO 56 19 20 GND -
SPI0_MI GPIO 55 21 22 GPIO 18 PCM_CLK
SPI0_CK GPIO 54 23 24 GPIO 53 SPI0_CSN
- GND 25 26 GPIO 20 PCM_RX
I2C_SDA1 GPIO 57 27 28 GPIO 58 I2C_SCL1
GPIO 126 29 30 GND -
I2S0_BCK GPIO 74 31 32 GPIO 72 I2S0_DATA_IN
I2S0_LRCK GPIO 73 (?) 33 34 GND -
I2S0_DATA GPIO 49 (M) 35 36 GPIO 19 PCM_SYNC
SPDIF_IN1 GPIO 202 37 38 INT0 GPIO 22 (*) / PCM_RST_IN
- GND 39 40 GPIO 200 SPDIF_OUT

Zum Anzeigen hier klicken ⇲

Zum Verstecken hier klicken ⇱

main spare
Pin 1 3V3 -
Pin 2 5V -
Pin 3 GPIO 75 I2C_SDA0
Pin 4 5V -
Pin 5 GPIO 76 I2C SCL0
Pin 6 GND -
Pin 7 GPIO 206 PWM3
Pin 8 GPIO 82 UART1 TX
Pin 9 GND -
Pin 10 GPIO 81 UART1 RX
Pin 11 GPIO 80 UART0 TX
Pin 12 Int2 GPIO 24 (*) / UCTS1
Pin 13 GPIO 79 UART0 RX
Pin 14 GND -
Pin 15 GPIO 205 PWM2
Pin 16 GPIO 25 / Int3 URTS1
Pin 17 3V3 -
Pin 18 GPIO 21 PCM_TX
Pin 19 GPIO 56 SPI0_MO
Pin 20 GND -
Pin 21 GPIO 55 SPI0_MI
Pin 22 GPIO 18 PCM_CLK
Pin 23 GPIO 54 SPI0_CK
Pin 24 GPIO 53 SPI0_CSN
Pin 25 GND -
Pin 26 GPIO 20 PCM_RX
Pin 27 GPIO 57 I2C_SDA1
Pin 28 GPIO 58 I2C_SCL1
Pin 29 GPIO 126
Pin 30 GND -
Pin 31 GPIO 74 I2S0_BCK
Pin 32 GPIO 72 I2S0_DATA_IN
Pin 33 GPIO 73 (?) I2S0_LRCK
Pin 34 GND -
Pin 35 GPIO 49 (M) I2S0_DATA
Pin 36 GPIO 19 PCM_SYNC
Pin 37 GPIO 202 SPDIF_IN1
Pin 38 INT0 GPIO 22 (*) / PCM_RST_IN
Pin 39 GND -
Pin 40 GPIO 200 SPDIF_OUT
(*) special GPIO need memory-patch and mode-set in 4.4.70
(?) currently not working
(M) mode-setting needed

Kernel 4.4.70

Access standard GPIO

root@bpi-r2:~# GPIO=/sys/devices/platform/1000b000.pinctrl/mt_gpio
root@bpi-r2:~# echo "mode 25 0" >$GPIO #not needed for every GPIO
root@bpi-r2:~# echo "dir 25 1" >$GPIO
root@bpi-r2:~# echo "out 25 1" >$GPIO

works with LED on Pin 14 (-) and Pin 16 (+), incl. resistor (220 Ohm)

Access special GPIO

for the GPIOs 22/(23??)/24 it is neccessary to set a register (siehe issue#17 comment #15) mwrite

root@bpi-r2:~# ./mwrite /dev/mem 0x10005b10 0x00000038
./mwrite offset : 10005b10, val : 00000038
b6f03b10
root@bpi-r2:~# GPIO=/sys/devices/platform/1000b000.pinctrl/mt_gpio
root@bpi-r2:~# echo "dir 24 1" >$GPIO
root@bpi-r2:~# echo "out 24 1" >$GPIO
root@bpi-r2:~# echo "mode 24 0" >$GPIO

for GPIO24 (pin 12) i have to set mode to 0

Kernel 4.14

GPIO_SYSFS and CONFIG_DEBUG_GPIO must be set in Kernel-Config (.config)

Access standard GPIO

root@bpi-r2# mount -t debugfs none /sys/kernel/debug                                                                                            
root@bpi-r2# cat /sys/kernel/debug/pinctrl/1000b000.pinctrl/gpio-ranges                                                                         
GPIO ranges handled:                                                                                                                 
0: 1000b000.pinctrl GPIOS [232 - 511] PINS [0 - 279] #base=232, first value of GPIOS
root@bpi-r2# GPIO_NO=$((232+25))  #base + number of gpio
root@bpi-r2# echo $GPIO_NO
257                                                                                                                                  
root@bpi-r2# echo $GPIO_NO > /sys/class/gpio/export

Pin 14=GND/16=GPIO25 (+)

GPIO as Output

root@bpi-r2# echo out > /sys/class/gpio/gpio${GPIO_NO}/direction
root@bpi-r2# echo 1 > /sys/class/gpio/gpio${GPIO_NO}/value
root@bpi-r2# echo 0 > /sys/class/gpio/gpio${GPIO_NO}/value

used for LED+resistor (220 Ohm) on Pin 14=GND/16=GPIO25 (+)

GPIO as Input

now try with high-active button-circuit on GPIO 200 (pin 40 between button and resistor, using pin 39 as GND [resistor] and pin 17 as 3v3-vcc)

[10:54] root@bpi-r2:~# echo in > /sys/class/gpio/gpio${GPIO_NO}/direction
[10:56] root@bpi-r2:~# cat /sys/class/gpio/gpio${GPIO_NO}/value
0 #button not pressed 
[10:56] root@bpi-r2:~# cat /sys/class/gpio/gpio${GPIO_NO}/value
1 #button pressed
[10:56] root@bpi-r2:~# cat /sys/class/gpio/gpio${GPIO_NO}/value
0 #button not pressed
#check every 1/4s
watch -n 0.25 cat /sys/class/gpio/gpio${GPIO_NO}/value

Special GPIO

memory-hack (like in 4.4.70) not needed

here example for GPIO24 (pin12):

root@bpi-r2# GPIO_NO=$((232+24))
root@bpi-r2# echo $GPIO_NO > /sys/class/gpio/export
root@bpi-r2# echo out > /sys/class/gpio/gpio${GPIO_NO}/direction
root@bpi-r2# echo 1 > /sys/class/gpio/gpio${GPIO_NO}/value

LED becomes on :)

on-board LEDs

on-board leds used here are near the power-socket (not next to gpio)

http://forum.banana-pi.org/t/control-on-board-leds/4287/13

on ⇒

echo 1 > /sys/class/leds/bpi-r2:isink:green/brightness

off ⇒

echo 0 > /sys/class/leds/bpi-r2:isink:green/brightness

blink (creates delay_on/off-nodes for frequency) ⇒

echo timer > /sys/class/leds/bpi-r2:isink:green/trigger

change blink frequency (on and off time in ms) ⇒

echo 100 > /sys/class/leds/bpi-r2:isink:green/delay_on
echo 100 > /sys/class/leds/bpi-r2:isink:green/delay_off

in my tests, green is blinking by default (red+blue are simply on/off), i don't know how to disable blinking of green led

L=/sys/class/leds/bpi-r2\:isink
echo 0 > $L:red/brightness         #goes off 
echo 1 > $L:red/brightness         #goes on
echo 0 > $L:green/brightness       #goes off 
echo 1 > $L:green/brightness       #starts blinking

UART

change DTS(i)

with Kernel 4.4.x the DeviceTree-sections are missing, these can be copied from a newer Kernel (dtsi). in the *bpi*.dts or *bananapi*.dts set state to enabled

definitions in the mt7623.dtsi: http://elixir.free-electrons.com/linux/v4.13-rc7/source/arch/arm/boot/dts/mt7623.dtsi

now in bananapi.dts set “status=okay” for your desired uart

notice that in mt7623.dtsi first must come uart2 then the others, else after uboot-message “Starting Kernel” no more output is shown

Uart3 can be routed to UCTS2/URTS2. These ports are next to Debug-UART-connector (here)

port preferences

#show preferences of serial port (replace ttyS2 with your port or ttyUSB0 if a USB2serial-adapter is used):
stty -F /dev/ttyS2 -a
 
#set speed to 9600 baud, 8 bits, 1 stop bit, no parity:
stty -F /dev/ttyS2 9600 cs8 -cstopb -parenb
 
#deactivate processing (character conversion,linebreaks,...)
stty -F /dev/ttyS2 -opost
 
#raw Modus
stty -F /dev/ttyS2 raw

Usage

pin 8/10 = uart1 (tx/rx) = 11003000
pin 11/13 = uart0 (tx/rx) = 11002000
#!/bin/bash
DEV=/dev/ttyS2
#stty -F ${DEV} sane
#stty -F ${DEV} 9600 cs8 -cstopb -parenb -crtscts -echo
stty -F ${DEV} 9600 cs8 -cstopb -parenb raw -echo
 
dmesg | grep "ttyS.*MMIO" | sed 's/^\[.*\] \(\d*.*\) at.*$/\1/'
 
echo "11002000 = uart0 (tx/rx) = pin 11/13"
echo "11003000 = uart1 (tx/rx) = pin 8/10"
 
echo "using $DEV"
echo "send data using \"echo \"AT\" >$DEV\""
 
while read line; do
#  if [[ -n "$line" ]]; then
    echo "["$(date "+%Y-%m-%d %H:%M:%S")"] received: "$line
#  fi
done < <(cat $DEV)
echo "AT" >/dev/ttyS2

simple example for Arduino (Nano)

uart-bpi.jpg uart-levelshifter.jpg uart-arduino.jpg

PI             Levelshifter       Arduino
1 (3V3)  -------  LV   HV -------- 5V
6 (GND)  ---------  GND  --------- GND
8 (TX)   ------- LV2  HV2 -------- RX
10 (RX)  ------- LV1  HV1 -------- TX

PWM

kernel-option PWM_MEDIATEK must be set (module possible), depends on PWM(=y)

using gpio 206 (pin 7) as pwm3

echo 3 >/sys/class/pwm/pwmchip0/export
echo 200000 >/sys/class/pwm/pwmchip0/pwm3/period
echo 100000 >/sys/class/pwm/pwmchip0/pwm3/duty_cycle
echo 1 >/sys/class/pwm/pwmchip0/pwm3/enable

https://www.kernel.org/doc/Documentation/pwm.txt

period The total period of the PWM signal (read/write). Value is in nanoseconds and is the sum of the active and inactive time of the PWM.
duty_cycle The active time of the PWM signal (read/write). Value is in nanoseconds and must be less than the period.
period=200000ns=200ms=5kHz
duty_cycle=100000ns=1/2 period=50% high + 50% low Signal

currently output has the wrong frequency (1kHz instead of 5kHz) see forum and issue

2018-03-02: frequency is now right: Commit in 4.14-main

SPI

I2C

how to add a i2c RTC

apt-get install i2c-tools
[17:13] root@bpi-r2:~# modprobe i2c-dev                                         
[17:14] root@bpi-r2:~# i2cdetect -y 0

added an rtc ds1307 (with removed pullups) to i2c0 (I2C_SDA0=pin3, I2C_SCL0=pin5, 5V=pin4, GND=pin6)

#!/bin/bash
modprobe i2c-dev
modprobe rtc-ds1307
echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-0/new_device
#cat /sys/class/i2c-dev/i2c-0/device/0-0068/rtc/rtc0/time
#read rtc
hwclock -r
#set system-clock to rtc-value
#hwclock -s
#set rtc to system-time
#hwclock -w

1Wire

thanks to user phil from bpi-r2-forum

To enable w1-gpio on GPIO 19 add the following to the main node of mt7623n-bananapi-bpi-r2.dts

w1 {
   pinctrl-names = “default”;
   compatible = “w1-gpio”;
   gpios = <&pio 19 0>;
   status = “okay”;
}; 

dts for kernel 4.9 with 1wire-node

add settings to kernel config

CONFIG_W1=m
CONFIG_W1_MASTER_GPIO=m
CONFIG_W1_SLAVE_THERM=m

and recompile the kernel

Your devices should now show up at /sys/bus/w1/devices/

GPS-PPS

http://mtnstormdaq.com/blog/2012/10/gps-pps-use-as-a-time-reference/

phil on bpi-r2-forum got pps working with kernel 4.9

HW-module

adding this to main-section of mt7623n-bananapi-bpi-r2.dts:

pps {
   pinctrl-names = “default”;
   compatible = “pps-gpio”;
   gpios = <&pio 72 0>;
   status = “okay”;
}; 

modified 4.9 dts

and add this options in the kernel-config for GPIO PPS support:

CONFIG_PPS=m
CONFIG_PPS_CLIENT_LDISC=m
CONFIG_PPS_CLIENT_GPIO=m

thermal

not really gpio, but i wont spend an own page

cat /sys/class/thermal/thermal_zone0/temp

http://forum.banana-pi.org/t/lm-sensors-support/4145/30

Discussion

en/bpi-r2/gpio.txt · Last modified: 2018/11/23 13:33 by frank