CAN Communication Problem OPENMV CAM M7

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zenertek
Posts: 2
Joined: Wed Aug 29, 2018 7:15 am

CAN Communication Problem OPENMV CAM M7

Postby zenertek » Wed Aug 29, 2018 7:27 am

Hello,

I am using 'openmv cam m7' at motion detection project. I have to send data with CANBUS to other nodes. But I have getting some error. CAn you help me with this?

Code: Select all

# Hello World Example
#
# Welcome to the OpenMV IDE! Click on the green run arrow button below to run the script!

import sensor, image, os, time, pyb
from pyb import  UART, CAN

TRIGGER_THRESOLD = 5
p_x = 320
p_y = 240

sensor.reset()                      # Reset and initialize the sensor.
sensor.set_pixformat(sensor.GRAYSCALE) # Set pixel format to RGB565 (or GRAYSCALE)
sensor.set_framesize(sensor.QVGA)   # Set frame size to QVGA (320x240)
sensor.set_windowing((p_x, p_y))
sensor.skip_frames(time = 2000)     # Wait for settings take effect.
sensor.set_auto_whitebal(False)
clock = time.clock()                # Create a clock object to track the FPS.

#canbus communication config
can = pyb.CAN(2, CAN.NORMAL)
can.init(pyb.CAN.NORMAL, extframe=False, prescaler=18, sjw=1, bs1=8, bs2=3) #250kb/s
# APB1 = 54MHz, Prescaler 18 et 250kB/s --> 12 time quanta par bit (1 + 8 + 3 = 12)
#uart communication config
uart = UART(1)
uart.init(1152000, bits=8, parity=None, stop=1, timeout=1000, flow=0, timeout_char=0, read_buf_len=64)

#bacground image take and save to sdcard
if not "temp" in os.listdir(): os.mkdir("temp")
sensor.skip_frames(time = 2000)
bgImage = sensor.snapshot()         #.save("temp/bg.bmp")
#bgImage.save("temp/bg.bmp")

while(True):
    clock.tick()                    # Update the FPS clock.
    img = sensor.snapshot()         # Take a picture and return the image.

    img.difference("temp/bg.bmp")


    hist = img.get_histogram()
    diff = hist.get_percentile(0.99).l_value() - hist.get_percentile(0.90).l_value()
    triggered = diff > TRIGGER_THRESOLD


    print(clock.fps(), triggered)              # Note: OpenMV Cam runs about half as fast when connected
                                               # to the IDE. The FPS should increase once disconnected.
User avatar
kwagyeman
Posts: 2462
Joined: Sun May 24, 2015 2:10 pm

Re: CAN Communication Problem OPENMV CAM M7

Postby kwagyeman » Wed Aug 29, 2018 12:35 pm

Hi, I bought the hardware to validate CAN bus communication but I have yet to actually check operation. The hardware on the MCU is definitely there and MicroPython supplies a driver for it but I can't tell you if anything works or not just yet. If you need CAN right now I'd recommend you to connect an Arduino or something to the OpenMV CAM via a UART and use the Arduino as a CAN bridge device.
Nyamekye,
zenertek
Posts: 2
Joined: Wed Aug 29, 2018 7:15 am

Re: CAN Communication Problem OPENMV CAM M7

Postby zenertek » Wed Aug 29, 2018 12:50 pm

Ok than. Thank you for information.
bauer-san
Posts: 1
Joined: Mon Sep 03, 2018 3:28 pm

Re: CAN Communication Problem OPENMV CAM M7

Postby bauer-san » Mon Sep 03, 2018 3:35 pm

@zener, which error do you get? Is the error coming from the import line

Code: Select all

from pyb import  UART, CAN
Which firmware are you using?
Erik
Posts: 8
Joined: Wed Jan 17, 2018 10:27 am

Re: CAN Communication Problem OPENMV CAM M7

Postby Erik » Thu Sep 06, 2018 2:46 pm

I can vouch for CAN working on the M7, I've been using it without any issues.
Your code seems fine, apart from the fact that you never use the CAN bus to send or receive messages.
Echoing the questions from @bauer-san, what firmware are you using and what errors are you seeing?
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iabdalkader
Posts: 629
Joined: Sun May 24, 2015 3:53 pm

Re: CAN Communication Problem OPENMV CAM M7

Postby iabdalkader » Thu Sep 06, 2018 3:00 pm

Hi everyone, please see this issue:

https://github.com/openmv/openmv/issues/370

The CAN module was disabled by mistake in the last release, and it has been fixed and will be available in the next release. For now you can either use FW 3.0.0 or wait for 3.2.0

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