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RockpiS/dev/libmraa

< RockpiS‎ | dev
    ROCK Pi S >  Development >  Install Libmraa 

Libmraa on ROCK Pi S

This guide describes how to use libmraa on ROCK Pi S.

Install essential packages

Package libmraa is in the Radxa APT bionic-stable and buster-stable repositories.

Execute the following commands to add Radxa APT

rock@rockpis:~$ export DISTRO=bionic-stable      # for Bionic

or

rock@rockpis:~$ export DISTRO=buster-stable      # for Buster
rock@rockpis:~$ echo "deb http://apt.radxa.com/$DISTRO/ ${DISTRO%-*} main" | sudo tee -a /etc/apt/sources.list.d/apt-radxa-com.list

Get the pub key

rock@rockpis:~$  wget -O -  apt.radxa.com/buster-testing/public.key | sudo apt-key add -

Install essential packages:

rock@rockpis:~$ sudo apt-get update
rock@rockpis:~$ sudo apt-get install -y rockchip-overlay rockpis-dtbo libmraa # libmraa version: >=0.4
rock@rockpis:~$ sudo apt-get install -y linux-4.4-rockpis-latest # ROCK Pi S kernel version: >= 4.4.143-47

Install compiler:

rock@rockpis:~$ sudo apt install -y build-essential

Enable interface

See ROCK Pi S GPIO pintout. ROCK Pi S has a 26-pin colorful expansion header. Each pin is distinguished by color. mraa define is shown below:

Hardware V12

16 GPIO:

   PIN03      GPIO2_A2
   PIN05      GPIO2_B0
   PIN07      GPIO2_B3
   PIN09      GPIO4_C4
   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
   PIN26      GPIO1_B2

3 I2C:

   PIN23      I2C0_SDA
   PIN24      I2C0_SCL
   PIN3       I2C1_SCL
   PIN5       I2C1_SDA
   PIN13      I2C3_SDA
   PIN15      I2C3_SCL
  

1 SPI:

   PIN19      SPI2TX        //must disable i2c0
   PIN21      SPI2RX        //must disable i2c0
   PIN23      SPI2CLK
   PIN24      SPI2CSN

3 UART:

   PIN8       UART0_TX
   PIN10      UART0_RX
   PIN23      UART1_TX
   PIN24      UART1_RX
   PIN19      UART2_RX
   PIN21      UART2_TX

2 PWM:

   PIN11      PWM2
   PIN13      PWM3

1 ADC:

   PIN26      ADC_IN0          //the measure voltage must lower than 1.8v

For those ROCK Pi S system images released after March 1st, 2020, the configuration file is /boot/uEnv.txt. For more details, follow this guide, Device tree overlays.

For those ROCK Pi S system images released before March 1st, 2020, the configuration file is /boot/hw_intfc.conf.

Test

Package libmraa provides some examples for testing spi, uart, i2c, gpio, etc. We way use the c files in /usr/local/share/mraa/examples/c.

And we copy them to home directory.

rock@rockpis:~/mraa-examples$ cp -av /usr/local/share/mraa/examples/c /home/rock/mraa-examples

You should pay more attention to the Black Bold words when modifying configuration file /boot/uEnv.txt.

GPIO test

Use mraa-gpio tool to test

root@rockpis:~# mraa-gpio list
01         3V3: 
02          5V: 
03     I2C_SDA: GPIO I2C  
04          5V: 
05     I2C_SCL: GPIO I2C  
06         GND: 
07 I2S0_8CH_MC: GPIO 
08    UART0_TX: GPIO UART 
09         GND: 
10    UART0_RX: GPIO UART 
11 PWM2,I2C3_S: GPIO I2C  PWM  
12 I2S0_8CH_SC: GPIO 
13 PWM3,I2C3_S: GPIO I2C  PWM  
14         GND: 
15    SPDIF_TX: GPIO 
16 I2S0_8CH_SD: GPIO 
17         3V3: 
18 I2S0_8CH_SD: GPIO 
19 UART1_RTSN,: GPIO SPI  UART 
20         GND: 
21 UART1_CTSN,: GPIO SPI  UART 
22 I2S0_8CH_LR: GPIO 
23 UART1_RX,I2: GPIO I2C  SPI  UART 
24 UART1_TX,I2: GPIO I2C  SPI  UART 
25         GND: 
26     ADC_IN0: AIO 
root@rockpis:~# mraa-gpio set 15 1           #pin15 pull high
root@rockpis:~# mraa-gpio set 15 0           #pin15 pull high
PWM test

ROCK Pi S V1.2 provides 2 PWM, PWM2 and PWM3. It is necessary to enable PWM1, PWM2 and PWM3 at the same time if you need PWM function.

Firstly, modify the /boot/uEnv.txt file to add the following

root@rockpis:~# cat /boot/uEnv.txt
verbosity=7
overlay_prefix=rockchip
rootfstype=ext4
fdtfile=rockchip/rk3308-rock-pi-s.dtb
overlays=rk3308-console-on-uart0 rk3308-pwm1 rk3308-pwm2 rk3308-pwm3
rootuuid=37055840-4ec4-444f-979b-9e47ee4bd848
initrdsize=0x64d1d4
kernelversion=4.4.143-47-rockchip-g495ff574976c
initrdimg=initrd.img-4.4.143-47-rockchip-g495ff574976c
kernelimg=vmlinuz-4.4.143-47-rockchip-g495ff574976c


Modify the macro PWM in /home/rock/mraa-examples/pwm.c as follows to test PWM2. To test PWM3, change #define PWM 11 to #define PWM 13.

/* PWM declaration */
#define PWM 11

Save and compile pwm.c

rock@rockpis:~/mraa-examples$ gcc -o pwm pwm.c -lmraa
rock@rockpis:~/mraa-examples$ sudo ./pwm 
PWM value is 0.010015
PWM value is 0.019985
PWM value is 0.030000
PWM value is 0.040014
PWM value is 0.049984
PWM value is 0.059999
I2C test

ROCK Pi S V1.2 provides 3 I2C,There are I2C0 ,I2C1, I2C3. If you need the I2C function, you can turn on one or more of them.

Firstly, modify the /boot/uEnv.txt file to add the following

root@rockpis:~# cat /boot/uEnv.txt
verbosity=7
overlay_prefix=rockchip
rootfstype=ext4
fdtfile=rockchip/rk3308-rock-pi-s.dtb
overlays=rk3308-console-on-uart0  rk3308-i2c0 rk3308-i2c1 rk3308-i2c3
rootuuid=37055840-4ec4-444f-979b-9e47ee4bd848
initrdsize=0x64d1d4
kernelversion=4.4.143-47-rockchip-g495ff574976c
initrdimg=initrd.img-4.4.143-47-rockchip-g495ff574976c
kernelimg=vmlinuz-4.4.143-47-rockchip-g495ff574976c

We use MPU6050 tets i2c. Modify the macro MPU6050 in /home/rock/mraa-examples/i2c_mpu6050.c ,as follows to test I2C0. To test I2C1 and I2C3, change #define I2C_BUS 0 to #define I2C_BUS 1 or#define I2C_BUS 3 .

  /* mraa header */
  #include "mraa/i2c.h"
  #define I2C_BUS 0
  

Save and compile pwm.c

rock@rockpis:~/mraa-examples$ gcc -o i2c_mpu6050 i2c_mpu6050.c  -lmraa
rock@rockpis:~/mraa-examples$ sudo ./i2c_mpu6050
accel: x:0 y:0 z:0
gyro: x:-10 y:1 z:7
  
accel: x:0 y:0 z:0
gyro: x:107 y:-12 z:69
   
accel: x:0 y:0 z:0
gyro: x:6 y:136 z:-50
   
accel: x:0 y:0 z:0
gyro: x:-5 y:48 z:-103
     
accel: x:0 y:0 z:0
gyro: x:3 y:3 z:5
UART test

ROCK Pi S V1.2 provides 3 UART,There are uart0 ,uart1, uart2. If you need the uatr function, you can turn on one or more of them.

Firstly, Disable console and enable uart0 for uart test.modify the /boot/uEnv.txt file to add the following

root@rockpis:~# cat /boot/uEnv.txt 
verbosity=7
overlay_prefix=rockchip
rootfstype=ext4
fdtfile=rockchip/rk3308-rock-pi-s.dtb
overlays=rk3308-uart0 rk3308-uart1 rk3308-uart2
console=
rootuuid=c3800af9-fa58-4fb3-bb56-e52fd04837ba
initrdsize=0x5c96c3
kernelversion=4.4.143-47-rockchip-g495ff574976c
initrdimg=initrd.img-4.4.143-47-rockchip-g495ff574976c
kernelimg=vmlinuz-4.4.143-47-rockchip-g495ff574976c

Here set console to NULL value.

then reboot . use ssh connect to rockpis,we must have 2 windows,one is for send data,anothor is for receive.

send command follow:

rock@rockpis:~$ sudo mraa-uart dev 0 baud 1500000 send  radxa

Another window sets the baud 1500000 and receives the data

radxa

receive command follow:

rock@rockpis:~$ sudo mraa-uart dev 0 baud 1500000 recv  1000
radxa
SPI test

Firstly, modify the /boot/uEnv.txt file.

root@rockpis:~# cat /boot/uEnv.txt
verbosity=7
overlay_prefix=rockchip
rootfstype=ext4
fdtfile=rockchip/rk3308-rock-pi-s.dtb
overlays=rk3308-console-on-uart0 rk3308-spi-spidev
param_spidev_spi_bus=2
rootuuid=37055840-4ec4-444f-979b-9e47ee4bd848
initrdsize=0x64d1d4
kernelversion=4.4.143-47-rockchip-g495ff574976c
initrdimg=initrd.img-4.4.143-47-rockchip-g495ff574976c
kernelimg=vmlinuz-4.4.143-47-rockchip-g495ff574976c

then execute command, sync, followed by reboot.

Create file test-spi.c and add the following contents.

rock@rockpis:~/mraa-examples$ cat test-spi.c 
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>

/* mraa header */
#include "mraa/spi.h"

/* SPI declaration */
#define SPI_BUS 2

/* SPI frequency in Hz */
#define SPI_FREQ 10000000
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;
    }
   
    j = 10;
    while(j) {
  	j--;
        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;
}
rock@rockpis:~/mraa-examples$ gcc -o test-spi test-spi.c -lmraa

Then short pin19 and pin21 and run test-spi

rock@rockpis:~/mraa-examples$ sudo ./test-spi 
0xaa
0xaa
0xaa
0xaa
0xaa
0xaa
0xaa
0xaa
0xaa
0xaa
MRAA: SUCCESS
ADC test

connect signal you want to measure, and then compile mraa example c file, aio.c, to test.

rock@rockpis:~/mraa-examples$ gcc -o aio aio.c -lmraa
rock@rockpis:~/mraa-examples$ sudo ./aio
ADC A0 read 1A5 - 421
ADC A0 read float - 0.41153
ADC A0 read 1A5 - 421
ADC A0 read float - 0.41153
ADC A0 read 1A5 - 421
ADC A0 read float - 0.41153
ADC A0 read 1A5 - 421
ADC A0 read float - 0.41153

Development

More introduction of libmraa can look at libmraa official website.

Troubleshooting