I declare that I am using a CAN library which works with other boards, so right now I’d like to rule out that’s the problem.
Therefore, despite having configured the CAN and the code compile correctly, the messages are not received while using STM32F469-disco.
I read that the CAN configuration may have some issues with this card due to the pins used by I2C.
I2C uses the PB8-PB9 PIN for the display, but the CAN1 should use it as a PIN for communication. However, replacing the I2C PIN with PB6-PB7 and the CAN1 PIN with PB8-PB9 it doesn't work, i think I2C (and consequently QUADSPI) does not work properly with these other pins.
I also tried to use CAN2, with pins PB5 and PB13, but that doesn't work anyway.
Is there really this problem of "coexistence" between I2C and CAN? Or is it an option that is not to be considered and the problem is elsewhere?
Related
I'm working on a little project I wanted to see come to life using a NEOPIXEL WS2812B with a PI 4. I think I might be up against a hardware limitation and I'm curious if there's anyway around it. Heres the code I'm using
void send1()
{
//T1H
digitalWrite(DATA, HIGH);
//usleep(0.85);
//T1L
digitalWrite(DATA, LOW);
//usleep(0.4);
}
As you can see I've commented out the usleep stuff because I was having issues with the timing and I wanted to see the maximum switching speed I can get.
With that I get a switching speed of around 1.200us. The neopixels requires a 0.4 and 0.85us switching speed to work properly. Does anyone have any suggestions that can help get that number down? I'm just using a regular gpio pin. I'm rather new to playing around with the pi so I don't know all the tricks.
I did see this on pinout.xyz
The PWM0 output of GPIO 18 is particularly useful, in combination with
some fast, direct memory access trickery, for driving devices with
very specific timings. The WS2812 LEDs on the Unicorn HAT are a good
example of this in action.
That seems hopeful since the LEDs I'm using are the same model. but it doesn't really say much more about the tricks.
Direct Answer
You can try any of the following gpio libraries on rpi,
Rpi.GPIO (https://sourceforge.net/projects/raspberry-gpio-python/)
Gpiozero (https://gpiozero.readthedocs.io/)
Pigpio (http://abyz.me.uk/rpi/pigpio/)
Wiring Pi (deprecated, see author's statement)
Further Suggestion
It is not recommened to generate PWM signal directly from Raspberry Pi, because the linux kernel is not designed for real-time application and any other higher priority process could take over CPU from any running process, so basically you cannot make sure to have a constant PWM signal output. Probably NEOPIXEL LED will be flicking or changing color slightly in your case.
If you need better quality of PWM output, you are suggested to use a small I2C PWM module, e.g. many PCA9685-based boards. Your raspberry pi will control the module via I2C interface only when the value need to upadte, so your CPU are saved for your other applications.
I am trying to make some custom firmware for a MIDI controller (AKAI LPD8).
There is an STM32F102R8T6 chip in the unit.
I am trying to reach it with a programmer to wipe it, but it seems to not be responsive.
Some information and thing I have tried:
The firmware that came with the unit works, so the chip is not broken
Removed the components connected to the programming pins (PA9-PA10 and PA13-PA14)
I am able to pull BOOT0 high and have it not run the main program, but I am however not able to get a life sign using either an ST-Link2(clone) connected to PA13/14, nor a USB to serial adapter connected to PA9/PA10, so I am not sure what mode it is in
The connection has been checked, and RX-TX etc is the correct way around (but also for the sake of trying it all, I reversed the connections as well...).
Tried both the STM32CubeProgrammer and stm32flash, but none connects.
I am actually not sure if AKAI have locked the chip in such a way that you cannot even do a full chip erase and use the chip for something new? The NRST pin is strangely not doing anything to the running of the firmware either when I try to pull it low.
Is there a way to reprogram these chips when they come off of a commercial product, or are they permanently locked?
Any solution/tips?
Many of the STM32 parts have "proprietary code read-out protection" (google PCROP) which but you might be lucky and they haven't enabled it in the option bytes. Read the documentation for that and the bootloader documentation and get a good idea of what you expect it to do if it is enabled and if it isn't.
If you have a scope, try watching the SWD/JTAG pins to see if there is any response from the device. (If you aren't even sure if it is in reset then scope the crystal if there is one).
If you haven't got a scope, you might be able to to verify what it is doing by seeing if it sets the pins and pull-resistors to how they would be expected to be in the bootloader mode, eg: UART TX should be high if it is enabled, even it it isn't transmitting anything. Put a strong pull-down (~1k) on there and see if it still reads high.
After hours of trying different ways of making it work (also tried the alternate mapping of the UART port), and probed the TX pin as suggested by Tom V to no avail, I have given up working on that specific chip and ordered an upgrade from the STM32F4 family instead to replace it with. A lot more power and useful peripherals.
A bit of a non-answer to the specific question. Frustrating to not have found out what was wrong (chip or approach) but being mindful of the sunk cost fallacy, I think it was best to just replace the chip with a fresh one and start development from there.
I'm having trouble with i2c communication. In my i2c bus, i have 4 boards (STM32L4 Sensortiles) and sometimes one of them blocks the bus and the others stop communicating consequently. When I reset that one that blocks the bus, all boards starting working again.
In my debugs, this bug happened when HAL_I2C_GetState(&hi2c3) returns HAL_I2C_STATE_BUSY_RX, even my others i2c functions HAL_I2C_Slave_Receive_IT and HAL_I2C_Slave_Transmit_IT returns HAL_OK:
Any ideas what Im doing wrong? Thanks.
Using libraries like HAL leads to problems like this one. Why?
HAL users feel free from knowing your hardware as magic library will do everything for you.
HAL users usually do not know how the peripheral works and how to debug it.
HAL users do not bother to go through the magic HAL function to see what the problem is.
Posting some images form debugger will not help.
What you need to do:
Get even the cheapest logic analyzer (there are $10 on ebay) and record the communication. See if the slave keeps the clock or data line low. If yes toggle the clock pin 9 times to unblock the line
If nothing helps reset the I2C peripheral using RCC register (it has to be implemented on all connected boards).
I am working on a university project in which i need to interface pic18f4550 with i2c EEPROM.
I implemented the following circuit using proteus simulator. The following in my connections
when I implemented the interfacing on real, I faced a problem when the PIC reads from the eeprom. it is suspended and so I was not able to see if the reading operation was performed correctly.
What could be the problem?
You do need to make sure you are following the I2C protocol for reading an EEPROM, and that is best served with a state machine on a PIC.
Try sequencing through the following actions, making sure your flags are set correctly:
Start condition
Write to the EEPROM with the address to which you want to read.
Repeated Start condition.
Read from the EEPROM as many bytes as required (keep in mind that the EEPROM is paged, and you will roll over if you go past a page boundary.)
Stop condition
I'm not an Atmega pro by any means whatsoever. In fact, never worked with them. I'm trying to add an external eeprom using i2c interface to a device that uses an Atmega64 controller. From the datasheet, I see that pins 25 and 26 are labeled PD0/PD1 and are the SCL/SDA for i2c. That's fine and dandy. So then I go to the board and start tracing. I see that those go to a rocker switch with some simple circuitry that I haven't had a good look at yet, but I assumed it was something i2c compatible. But then what dawned on me was that this device has two such rockers so I expected to trace the other rocker back to the same two pins (since i2c is a bus that can have multiple slaves). Instead, they traced back to the two adjacent pins 27 and 28 labeled PD2/PD3 and RXD1/TXD1. Well, now that confused me.
I expected that I could add the memory in parallel on the SCL/SDA lines, but does what I now figure that what I discovered either means:
SCL/SDA is interchangeable with RXD1/RXD2 or
I'm confused on how SCL/SDA works and its not a bus or it can be used as a simple input?
Sadly, I'm not really sure what I'm asking. Can someone shed some light on this? Should I still be able to add the memory to SCL/SDA or probably not?
Thanks.
Steve
Nevermind, I found the answer. Its BOTH a bus and a simple input... either one or the other. In this case, its being used as an input so I can't also use it as a bus. Darn. Oh well.