I'd like some help to debug the example code provided by adafruit. I have connected a potentiometer and an analog servo motor which when using the python2 script give me values just fine. I took from this site: https://learn.adafruit.com/raspberry-pi-analog-to-digital-converters/mcp3008
Since I have to upgrade to python3 I looked into new tutorials here: https://learn.adafruit.com/mcp3008-spi-adc/python-circuitpython
The problem I have is no matter what pin value I give in the board I always get 0 values. The pin I use for mcp3008 selector is BCM 22:
I've also provided an image of the connection here:
mcp3008 potentiometer raspberry pi zero w
import busio
import digitalio
import board
import adafruit_mcp3xxx.mcp3008 as MCP
from adafruit_mcp3xxx.analog_in import AnalogIn
spi = busio.SPI(clock=board.SCK, MISO=board.MISO, MOSI=board.MOSI)
cs = digitalio.DigitalInOut(board.D5)
mcp = MCP.MCP3008(spi, cs)
What am I doing wrong? Thanks a lot for your time.
It turns out the raspberry pi required restart which surprised me as I suspect it's because I installed the adafruit packages.
Related
I am having troubles using an I2C sensor with the Beagle Bone Black (BBB). The BBB is running a newly flashed 18.04 Ubuntu image specifically for the BBB.
I wired the sensor (VIN, GND, SCL, SDA) to the corresponding I2C2 pins (4, 2, 19, 20) on the BBB using the below pinout.
The sensor is supposed to be using address 0x40, but scanning I2C2 (using i2cdetect -r 2) does not show the sensor.
I have tested this with two separate sensors as I thought at first I may have fried the original sensor somehow, but the results are the same. In fact, running the I2C2 scan command yields the exact same results when nothing is connected at all.
I have read in many places that I2C2 may not be enabled by default, but I assume it is enabled in my case as I can scan I2C2 without getting an error. Is this assumption incorrect? Again, this is a freshly flashed BBB, and I have not enabled/disabled anything - it should be in the default state.
I have also verified the connectivity of my wires between the sensor and BBB. The voltage between VIN and GND on the chip is 3.3V, so it is definitely being powered.
Why can't I connect to my I2C sensors using the BBB?
it could be that the source you are using is outdated or not a viable entry for i2c.
Also, you could use this command to make sure i2c2 pins are available:
config-pin p9.21 i2c
config-pin p9.22 i2c
This may work, also. If this does not work, please reply with your entire source.
Seth
P.S. Also, if you have time, you may want to get an i2c library to use if your software falls short of setting up your own i2c library. They have smbus2 you can install with pip and other i2c libraries out there still.
Here are a few things you should check (in random order).
List all I2C buses wich i2cdetect -l and try them all. Depending on the platform, the i2c bus number in Linux may be different from the peripheral number used in the datasheet and pinout. E.g. "I2C2" might be bus i2c-1 or i2c-3 in Linux).
Use an oscilloscope or logical analyzer to see if the SCL and SDA lines are being driven. If they aren't check the bus number as above. If they are, then check whether the device gives an ACK; if it doesn't, anything else will never work: double-check the chip slave address. There are cheap logical analyzers that you can buy and user with pulseview.
Simply load the Linux driver for your chip (see the kernel docs on how to do it from userspace for a quick test). Then see check if the device appears or use dmesg to see any kernel error messages while probing.
when using the GPIO library on the Raspberry PI and having an example code like this:
while True:
GPIO.setup(21, GPIO.OUT)
pwm = GPIO.PWM(21, 50)
pwm.start(0)
for i in range(0, 101, 2):
pwm.ChangeDutyCycle(i)
time.sleep(0.03)
for i in range(100, -1, -2):
pwm.ChangeDutyCycle(i)
time.sleep(0.03)
pwm.stop()
GPIO.cleanup(21)
time.sleep(1)
The code might stop suddenly after a while. No error, just no changes via pwm are recognized any longer. Anyone got an idea why this is?
This issue has been mentioned here in the old sourceforge repo:
https://sourceforge.net/p/raspberry-gpio-python/tickets/111/
https://sourceforge.net/p/raspberry-gpio-python/tickets/94/
Its because the GPIO library by default creates a new pthread for every call without cleaning up afterwards, but the number of threads might be limited to a number of 250 or so.
I created a fork of this repo (https://github.com/wuestkamp/raspberry-gpio-python) which solves this and contains instructions on how to use this on your PI.
Hi I am developed a board based on the Discovery L476 board (STM32L476VGT6) using MBED and after porting it to VisualGDB everything works great. The only thing that doesn't work is LPUART1. I hooked it to PB10(LPUART1_RX), PB11(LPUART1_TX) but whenever I declare the port in my code and download it, the program hangs and doesn't even start:
Serial RS232(PB_11, PB_10);
If I remove this line, the code works great (but I can't use this port)
I changed the pin definitions in PeripheralPins.c so PB10 and PB11 will function as the LPUART TX and RX pins: (I added the lines)
const PinMap PinMap_UART_RX[] = { {PB_10, LPUART_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF8_LPUART1)},
//
const PinMap PinMap_UART_TX[] = { {PB_11, LPUART_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF8_LPUART1)},
but it still doesn't work. Any ideas?
See https://github.com/ARMmbed/mbed-os/issues/5389, the baud rate needs to be set at [sys_clk / 4096 ... sys_clk / 3]. Sys clock on this device is running at 80MHz. You could fix it in the HAL for this board until a real fix is deployed.
I'm trying to hook up a MPU6050 with my NodeMCU board with Micropython flashed in it.
My current wiring is the following:
MPU6050 Board
Vcc 3.3v
Gnd Gnd
SDA D6
SCL D7
Through the command line, I've tried the following commands:
>>> from machine import Pin, I2C
>>> i2c = I2C(sda=Pin(12),scl=Pin(13))
>>> i2c.scan()
[]
>>>
12 and 13 were the GPIO values that I took from this pinout and I've also tried with the D1 and D2 pins as many people online do.
Although I plan to use a premade module for reading the MPU6050 values, I would have liked to see this by myself (the pre-made modules seem too overwhelming, so I wanted to see if I could do something by myself).
I'm getting quite crazy because everything seems fine to me (according to other people's wiring seen online too).
As always, thanks in advance!
Just in case someone else runs into this problem: After fighting for hours trying to get a NodeMCU work with a MCP23017 on micropython and getting the empty i2c.scan() I noticed that the problem is that for some reason micropython does not like using D1 & D2 (it does work when I test the same hardware configuration on arduino). Just use the following wiring for SDA and SCL in addition to the suggested wiring for the chip and you should be fine:
SDA: D6
SCL: D7
you should get:
>>> i2c = machine.I2C(scl=machine.Pin(13), sda=machine.Pin(12))
>>> i2c.scan()
[32]
Turns out the code was right and the cause was a faulty contact in the breadboard.
I'm very new to WebIOPi and I'm trying my first tests. First of all I apologize for my english.
I'm trying to get to work a RPi with a MCP3008 on CE0 and a MCP23S17 on CE1 with SPI bus.
My problem is that devices only work when connected on CE1 (so, when 23017 is on CE0 I am not able to set pins to be inputs or outputs and to set it on 1 or 0, but 3008 is on CE1 and I see its levels changing. When - vice versa - 23017 is on CE1 it is fully functional, but 3008 outputs stay still).
Due to this, I think it is not an hardware issue (I don't have much expertise in electronics, but luckily I don't build my circuits by myself :) ), I think it is a problem in WebIOPi config. Here is my WebIOPi config:
[DEVICES]
mcp1 = MCP23S17 chip:1 slave:0x27
adc0 = MCP3008 chip:0
I only added these two lines to my config file.
I did not touch anything else of my original WebIOPi installation.
In this case (adc0 fully functional, mcp1 not working), when loading the WebIOPi devices monitor I see adc0 levels working good and mcp1 pins randomly changing between being a input and an output and from 0 and 1.
May it be a config error?
Use python and spidev module instead! Look my answer on another thread for function for the mcp3008 chip.