Rockpi4/dev/libmraa
ROCK Pi 4 > Development > Install Libmraa
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Libmraa-rockpi4
Below is the instructions of how to install libmraa.
Install essential packages
Edit your /etc/apt/sources.list and add the following:
For Debian Stretch
deb http://apt.radxa.com/stretch/ stretch main
For Ubuntu bionic
deb http://apt.radxa.com/bionic/ bionic main
Get the pub key
wget -O - apt.radxa.com/stretch/public.key | sudo apt-key add -
Update
sudo apt-get update && sudo apt-get upgrade
Install essential packages:
sudo apt-get install -y rockchip-overlay && sudo apt-get install -y rockpi4-dtbo
Install the latest u-boot and kernel (optional)
apt-get install rockpi4b-rk-u-boot-latest
Manually run the u-boot flash script
/usr/local/sbin/rockpi4b_upgrade_bootloader.sh
Type YES to perform the uboot.img flashing.
then install kernel
apt-get install linux-base apt-get install linux-4.4-latest
After installation, check file /boot/extlinux/extlinux.conf. It lists all kernel version installed in ROCK Pi. The kernel corresponding to the first label is the newest version and the first boot option.
Enable interface
See rockpi4 GPIO pinout,ROCK Pi 4 has a 40-pin expansion header. Each pin is distinguished by color. mraa define follow:
27 GPIO:
PIN03 GPIO2_A2 PIN05 GPIO2_B0 PIN07 GPIO2_B3 PIN08 GPIO4_C4 PIN10 GPIO4_C3 PIN11 GPIO4_C2 PIN12 GPIO4_A3 PIN13 GPIO4_C6 PIN15 GPIO4_C5 PIN16 GPIO4_D2 PIN18 GPIO4_D4 PIN19 GPIO1_B0 PIN21 GPIO1_A7 PIN22 GPIO4_D5 PIN23 GPIO1_B1 PIN24 GPIO1_B2 PIN27 GPIO2_A0 PIN28 GPIO2_A1 PIN29 GPIO2_B2 PIN31 GPIO2_B1 PIN32 GPIO3_C0 PIN33 GPIO2_B4 PIN35 GPIO4_A5 PIN36 GPIO4_A4 PIN37 GPIO4_D6 PIN38 GPIO4_A6 PIN40 GPIO4_A7
2 I2C:
PIN3 I2C7_SDA PIN5 I2C7_SCL PIN27 I2C2_SCL PIN28 I2C2_SCL PIN29 I2C6_SCL PIN31 I2C6_SDA
2 SPI:
PIN19 SPI1TX //must disable uart4 PIN21 SPI1RX //must disable uart4 PIN23 SPI1_CLK PIN24 SPI1_CS PIN29 SPI2TX //must disable i2c6 PIN31 SPI2RX //must disable i2c6 PIN7 SPI2_CLK PIN33 SPI2_CS
1 UART:
PIN8 UART2_TX PIN10 UART2_RX PIN19 UART4_TX PIN21 UART4_RX
2 PWM:
PIN11 PWM0 PIN13 PWM1
1 ADC:
PIN13 ADC0 //the measure voltage must lower than 1.8v
modify /boot/hw_intfc.conf to enable pwm0,pwm1,uart2,uart4,i2c2,i2c6,i2c7 for test
root@localhost:/# cat boot/hw_intfc.conf # Hardware Interface Config # For more details, check https://wiki.radxa.com/Rockpi4/hardware/devtree_overlays. # Set "on" to enable the optional hardware interfaces while set "off" to disable. intfc:pwm0=off intfc:pwm1=off intfc:uart2=off intfc:uart4=off intfc:spi1=off intfc:spi2=off intfc:i2c2=off intfc:i2c6=off intfc:i2c7=off # Devicetree Overlay Enable, uncomment to enable .dtbo under /boot/overlays/. #intfc:dtoverlay=at24c02 #intfc:dtoverlay=two-color-led #intfc:dtoverlay=console-on-ttyS2 #intfc:dtoverlay=console-on-ttyS4 #intfc:dtoverlay=devspi1 #intfc:dtoverlay=devspi2 root@localhost:/#
then reboot to make them effective
Install libmraa
apt-get install libmraa
Test
test gpio
Use mraa-gpio tool to test
rock@localhost:~/mraa/build$ mraa-gpio list 01 3V3: 02 5V: 03 SDA7: GPIO I2C 04 5V: 05 SCL7: GPIO I2C 06 GND: 07 SPI2_CLK: GPIO SPI 08 TXD2: GPIO UART 09 GND: 10 RXD2: GPIO UART 11 PWM0: GPIO PWM 12 GPIO4_A3: GPIO 13 PWM1: GPIO PWM 14 GND: 15 GPIO4_C5: GPIO 16 GPIO4_D2: GPIO 17 3V3: 18 GPIO4_D4: GPIO 19 SPI1TX,TXD4: GPIO SPI UART 20 GND: 21 SPI1RX,RXD4: GPIO SPI UART 22 GPIO4_D5: GPIO 23 SPI1CLK: GPIO SPI 24 SPI1CS: GPIO SPI 25 GND: 26 ADC_IN0: AIO 27 SDA2: GPIO I2C 28 SCL2: GPIO I2C 29 SCL6,SPI2RX: GPIO I2C SPI 30 GND: 31 SDA6,SPI2TX: GPIO I2C SPI 32 GPIO3_C0: GPIO 33 SPI2CS: GPIO SPI 34 GND: 35 GPIO4_A5: GPIO 36 GPIO4_A4: GPIO 37 GPIO4_D6: GPIO 38 GPIO4_A6: GPIO 39 GND: 40 GPIO4_A7: GPIO rock@localhost:~/mraa/build$ rock@localhost:~/mraa/build$ sudo mraa-gpio set 40 1 //pin40 pull high rock@localhost:~/mraa/build$ sudo mraa-gpio set 40 0 //pin40 pull low root@localhost:~#
test i2c
Use mraa-i2c tool to test,we must have a i2c slave device,for example,we use I2C EEPROM:
rock@localhost:~/mraa/build$ mraa-i2c list Bus 0: id=07 type=linux default Bus 1: id=02 type=linux Bus 2: id=06 type=linux rock@localhost:~/mraa/build$ sudo mraa-i2c detect 0 //device on bus 0 //i2c7 00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: 50 51 52 53 54 55 56 57 -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- rock@localhost:~/mraa/build$ sudo mraa-i2c set 0 0x50 0x10 0x55 //write Device 50, Register = 10, Value = 55 rock@localhost:~/mraa/build$ sudo mraa-i2c get 0 0x50 0x10 //read Register 0X10 = 0X55
test spi
fristly,modiy /boot/hw_intfc.conf,if use spi1,must disable uart4,if use spi2,disable i2c6.follow:
rock@localhost:~/mraa/build$ cat /boot/hw_intfc.conf # Hardware Interface Config # For more details, check https://wiki.radxa.com/Rockpi4/hardware/devtree_overlays. # Set "on" to enable the optional hardware interfaces while set "off" to disable. intfc:pwm0=on intfc:pwm1=on intfc:uart2=on intfc:uart4=off intfc:spi1=on intfc:spi2=on intfc:i2c2=on intfc:i2c6=off intfc:i2c7=on # Devicetree Overlay Enable, uncomment to enable .dtbo under /boot/overlays/. #intfc:dtoverlay=at24c02 #intfc:dtoverlay=two-color-led #intfc:dtoverlay=console-on-ttyS2 #intfc:dtoverlay=console-on-ttyS4 intfc:dtoverlay=devspi1 #spi1 intfc:dtoverlay=devspi2 #spi2
If need debug console, you could uncomment intfc:dtoverlay=console-on-ttyS2
use c to test spi,compile spi.c,if use spi1,must disable
root@localhost:~# cat spi.c
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
/* mraa header */
#include "mraa/spi.h"
/* SPI declaration */
#define SPI_BUS 0
/* SPI frequency in Hz */
#define SPI_FREQ 400000
int
main(int argc, char** argv)
{
mraa_result_t status = MRAA_SUCCESS;
mraa_spi_context spi;
int i, j;
/* initialize mraa for the platform (not needed most of the times) */
mraa_init();
//! [Interesting]
/* initialize SPI bus */
spi = mraa_spi_init(SPI_BUS);
if (spi == NULL) {
fprintf(stderr, "Failed to initialize SPI\n");
mraa_deinit();
return EXIT_FAILURE;
}
/* set SPI frequency */
status = mraa_spi_frequency(spi, SPI_FREQ);
if (status != MRAA_SUCCESS)
goto err_exit;
/* set big endian mode */
status = mraa_spi_lsbmode(spi, 0);
if (status != MRAA_SUCCESS) {
goto err_exit;
}
while(1) {
printf("0x%x\n",mraa_spi_write(spi, 0xaa));
}
err_exit:
mraa_result_print(status);
/* stop spi */
mraa_spi_stop(spi);
/* deinitialize mraa for the platform (not needed most of the times) */
mraa_deinit();
return EXIT_FAILURE;
}
root@localhost:~# gcc spi.c -lmraa
then short pin19 and pin21 and run a.out
root@localhost:~# ./a.out 0xaa 0xaa ......
test pwm
for pwm python test,should install python and libpython2.7
apt-get install libpython2.7 python
use python script follow:
root@localhost:~# cat pwm.py
#!/usr/bin/env python
# Example Usage: Generates PWM at a step rate of 0.01 continuously.
import mraa
import time
x = mraa.Pwm(11) # pin11 pwm0
# x = mraa.Pwm(13) # pin13 pwm1
x.period_us(700)
x.enable(True)
value= 0.0
while True:
x.write(value)
time.sleep(0.05)
value = value + 0.01
if value >= 1:
value = 0.0
root@localhost:~#
then run pwm.py
root@localhost:~# ls pwm.py root@localhost:~# chmod +x pwm.py root@localhost:~# ./pwm.py
test uart
Disable console and enable uart2 and uart4 for uart test
root@localhost:/# cat boot/hw_intfc.conf # Hardware Interface Config # For more details, check https://wiki.radxa.com/Rockpi4/hardware/devtree_overlays. # Set "on" to enable the optional hardware interfaces while set "off" to disable. intfc:pwm0=on intfc:pwm1=on intfc:uart2=on intfc:uart4=on intfc:spi1=on intfc:spi2=off intfc:i2c2=on intfc:i2c6=off intfc:i2c7=off # Devicetree Overlay Enable, uncomment to enable .dtbo under /boot/overlays/. #intfc:dtoverlay=at24c02 #intfc:dtoverlay=two-color-led #intfc:dtoverlay=console-on-ttyS2 #intfc:dtoverlay=console-on-ttyS4 root@localhost:/#
then reboot. Connect your serial line to the corresponding serial port. use ssh connect to rockpi4,we must have 2 windows(ssh and serial console ),one is for send data,anothor is for receive.
send command follow:
sudo mraa-uart dev 0 baud 1500000 send data or sudo mraa-uart dev 1 baud 1500000 send data
receive command follow:
sudo mraa-uart dev 0 baud 1500000 recv 1000 or sudo mraa-uart dev 1 baud 1500000 recv 1000
the receive window will show the data
test adc
connect signal you want to measure,and then compile mraa examplec file to test.
rock@localhost:~/mraa$ ls examples/c/aio.c examples/c/aio.c gcc examples/c/aio.c -lmraa
then run a.out
More examples
More examples (including examples written in python and java) can be found at:
/usr/local/share/mraa/examples/