Why would the file system (CIRCUITPY) of an Adafruit board running CircuitPython not show up when connecting it to a suitable host via a micro usb cable?
This happens to me often, usually when I am copying files via Windows, most often with my trinket which uses the integrated chip flash memory rather than the separate SPI flash chip. Why? I don't know. A bug somewhere obviously. :)
So the solution.
Always save your work files locally or use a source code solution like git
Switch to the boot mode (double click reset)
Drag the erase.uf2 file to clear the flash memory
Drag the circuit python uf2 file to reflash python
Restore your files saved on your PC
Basically, I've made it a habit to assume the flash memory is temporary and volatile and not store any critical code only there.
You can read more about the erase uf2 and reflashing, general troubleshooting here:
https://learn.adafruit.com/welcome-to-circuitpython/troubleshooting
Besides your first answer about the cable, because of the relatively inexpensive nature of the boards and direct access to their power/ground sometimes the EPROMs that the file system are hosted on just go bad and give unexpected results. Best idea is to:
Test your environment with another board.
Reflash micro python on your board so you can start from scratch (didn't mention if you'd tried that).
JerryN mentioned the most common cause of this is using a USB cable with no data wires. Some USB cables are designed for power-only and have 2 rather than 4 conductors. These will power the device but will prevent mounting of the drive and use of the serial connection over USB.
Unfortunately these cables are often not marked as power-only so can be difficult to spot.
Another case is where CPLAYBOOT (this varies per board, e.g. GEMMABOOT, FEATHERBOOT, TRINKETBOOT) disappears on Windows. This can be caused by installation of the Arduino software which has an old, conflicting driver from 2007. More information on Adafruit: Circuit Playground Express: Troubleshooting.
A very rare case is a mis-seated USB connector. In my case the power was ok but the data wasn't for a good quality cable which had previously worked fine. Unplugging the USB cable at the host end and re-inserting it solved the problem.
Related
I have an Orange Pi + 2 single board computer with the ability to connect an external hard drive via SATA.
Armbian is installed on the hard disk, the bootloader is in the onboard memory of the board.
Any command to turn off the device leads to the same result: the indicators on the board go out, it is no longer available via SSH, but the hard disk, any devices connected via USB continue to work, and the image via HDMI is also displayed on the screen.
How to completely turn off the device so that the hard drive stops correctly?
I believe that if you are capable of powering the device off using the operating system's menu, then it should be safe to cut the power off from the device itself. I have a raspberry pi 4 and have a little USB-C adapter that has a simple power switch which makes this concept very convenient for me. Cutting power to a turned-on, working device is very dangerous as it can damage critical files that could be being written. For this reason, it is probably smart to back up the device and also make sure that you are powering the device off through the operating system so that it can finish editing core files in case it needs to.
I am working with a simple PIC18F2550 and I'm wondering about how to get a bootloader working on it. It's a very simple device with a USB port and CDC firmware. When I download Tiny Bootloader onto the pic, my PC doesn't recognize the device. Do I NEED to have a USB controller in my circuit in order for it to work? Such as the MAX232?
Would the same apply to the PIC32MX795F512L?
Thanks!
It is clear from the Tiny PIC boot loader documentation that it expects a UART connection rather than USB (that is what the MAX232 is for - it is an RS232 line driver).
You could simply do that and use an external serial to USB converter thus saving the code space required by the USB-CDC stack. Otherwise you will have to modify the boot loader code to use the CDC driver rather than the UART.
You will have to link the USB code with the boot loader, which will no doubt significantly increase its size. You may need therefore also to move the application start address to accommodate the boot loader. Furthermore, if the application needs USB comms, you may need a separate copy of the code in the application unless you provide a method of accessing the bootloader code from the application; which is possible, but not necessarily straightforward.
All that said, note the part at the end of the end of the page about extending the bootloader; On the face of it it seems unsuited to extension. Without looking at the code and its memory map, it is not clear why it has this constraint.
The PIC18F2550 has a USB interface built into it. It is called the "USB SIE" and there is a large section in the datasheet that documents it. If you make the right electrical connections, you should be able to connect your PIC18F2550 directly to a USB port without any active electronics between them. There is no reason you would need extra USB hardware just because you want to run a bootloader.
If you want to troubleshoot your problems with the bootloader, you should probably post another question with more details. It could be a problem with the PIC's configuration bits or something like that. I recommend trying to modify the bootloader to get it to blink an LED as a basic first step just so you can verify that you were able to get its code to run at all.
I am a physicist, and I had a revelation a few weeks ago about how I might be able to use my personal computer to get much finer control over laboratory experiments than is typically the case. Before I ran off to try this out though, I wanted to check the feasibility with people who have more expertise than myself in such matters.
The idea is to use the i/o ports---VGA, ethernet, speaker jacks, etc.---on the computer to talk directly to the sensors and actuators in the experimental setup. E.g. cut open one side of an ethernet cable (with the other end attached to the computer) and send each line to a different device. I knew a postdoc who did something very similar using a BeagleBone. He wrote some assembly code that let him sync everything with the internal clock and used the GPIO pins to effectively give him a hybrid signal generator/scope that was completely programmable. It seems like the same thing should be possible with a laptop, and this would have the additional benefit that you can do data analysis from the same device.
The main potential difficulty that I foresee is that the hardware on a BeagleBone is designed with this sort of i/o in mind, whereas I expect the hardware on a laptop will probably be harder to control directly. I know for example (from some preliminary investigation, http://ask.metafilter.com/125812/Simple-USB-control-how-to-blink-an-LED-via-code) that USB ports will be difficult to access this way, and VGA is (according to VGA 15 pin port data read and write using Matlab) impossible. I haven't found anything about using other ports like ethernet or speaker jacks, though.
So the main question is: will this idea be feasible (without investing many months for each new variation of the hardware), and if so what type of i/o (ethernet, speaker jacks, etc.) is likely to be the best bet?
Auxiliary questions are:
Where can I find material to learn how I might go about executing this plan? I'm not even sure what keywords to plug in on Google.
Will the ease with which I can do this depend strongly on operating system or hardware brand?
The only cable I can think of for a pc that can get close to this would be a parallel printer cable which is pretty much gone away. It's a 25 wire cable that data is spread across so that it can send more data at the same time. I'm just not sure if you can target a specific line or if it's more of a left to right fill as data is sent.
To use one on a laptop today would definitely be difficult. You won't find any laptops with parallel ports. There are usb to parallel cables and serial to parallel cables but I would guess that the only control you would have it to the usb or serial interface and not the parallel.
As for Ethernet, you have 4 twisted pair with only 2 pair in use and 2 pair that are extra.
There's some hardware that available called Zwave that you might want to look into. Zwave will allow you to build a network of devices that communicate in a mesh. I'm not sure what kind of response time you need.
I actually just thought of something that might be a good solution. Check out security equipment. There's a lot of equipment available for pc's that monitor doors, windows, sensors, etc. That industry might what your looking for.
I think the easiest way would be to use the USB port as a Human Interface Device (HID) and using a custom built PIC program and a PIC that includes the USB functionality to encode the data to be sent to the computer and in that way be able to program it independently from the OS due to the fact that all mayor OS have the HID USB functionality.
Anyways if you used your MIC/VGA/HDMI whatever other port you still need a device to encode the data or transmit it, and another program inside the computer to decode that data being sent.
And remember that different hardware has different software (drivers) that might decode the raw data in other odd ways rendering your IO hardware dependent.
Hope this helps, but thats why the USB was invented in the first place to make it hardware and os independent.
I have a device that came with an AC power adapter where the connector is a mini USB plug. The device however doesn't seem to power itself from a computer's USB port (using a standard USB-mini USB cable) unless a specific driver is installed. The driver is only available for Windows. I would like to charge the device from USB plugs on different platforms.
My question is: why isn't power getting to the device without the driver? Is a driver always required for a USB port to start giving power? Or is it this device that's specifically made not to take a charge unless some software routine triggers it to do so?
I guess my question can be summarized as: Is power not present on the USB cable or is it present but the device ignoring it. If the answer is the former, I'll be trying to figure out how to write software that will enable the voltage to always be present.
Thanks
Why isn't power getting to the device without the driver?
USB ports are always powered when the computer is on and the USB control software hasn't detected current overdraw.
Is a driver always required for a USB port to start giving power?
No, the USB port is always required to start off providing power to the device, otherwise the device could never initiate a connection.
Or is it this device that's specifically made not to take a charge unless some software routine triggers it to do so?
This can be complex. To meet the USB spec a device cannot pull more than a few mA until it's registered with the computer.
However, nearly every computer allows the USB port to pull the full 500mA (and more) before it'll shut the power off.
The device you're charging is being nice by not pulling any significant power until the computer gives permission.
Writing software won't help, the device has to register with the USB bus, which will best be done with the driver.
However, the plug in charger doesn't do that. It likely has shorted the two data lines of the USB plug together, which signals the USB device that it's not connected to a computer and can pull the full 500mA without waiting.
Take a USB extension cable, cut off the jacket, and short the data lines (green and yellow, sometimes) together on the end going to the USB device, and leave them cut without touching anything on the end going to the PC, and leave the read and black power wires connected through.
It might work. If not, take the wall charger apart and find out what it's doing with each of the four USB wires, and see if you can duplicate that.
This might be helpful if you are targeting a linux system.
This seems to be platform-specific. In Linux, USB ports are always energized, while on Windows they don't. Thumbdrives with LEDs turn off when unmounted in windows, but in Linux they stay lit. My cellphone's manual says that it can't be charged by a PC, but I regularly do on my linux machine, I guess that's because they don't have a driver and windows won't power up without one.
Have you tried plugging it into a 'dumb' USB port - like the one on a car charger? Those ports are pure power and don't create a USB network. I think.
Unless you have the hardware specs from the manufacturer, I think you are out of luck. You could try reverse engineering the driver to see what it does, but I'd expect it would be cheaper and easier just to buy one with cross platform drivers or charges without the driver.
I have been tasked to write a device driver for an embedded device which will communicate with the micro controller via the SPI interface. Eventually, the USB interface will be used to download updated code externally and used during the verification phase.
My question is, does anyone know of a good reference design or documentation or online tutorial which covers the implementation/design of the USB protocol stack/device driver within an embedded system? I am just starting out and reading through the 650 page USB v2.0 spec is a little daunting at the moment.
Just as a FYI, the micro controller that I am using is a Freescale 9S12.
Mark
Based upon goldenmean's (-AD) comments I wanted to add the following info:
1) The embedded device uses a custom executive and makes no use of a COTS or RTOS.
2) The device will use interrupts to indicate data is ready to be retrieved from the device.
3) I have read through some of the docs regarding Linux, but since I am not at all familiar with Linux it isn't very helpful at the moment (though I am hoping it will be very quickly).
4) The design approach, for now at least, it to write a device driver for the USB device then a USB protocol layer (I/O) would reside on top of the device driver to interpret the data. I would assume this would be the best approach, though I could be wrong.
Edit - A year later
I just wanted to share a few items before they vanish from my mind in case I never work on a USB device again. I ran into a few obstacles when developing code and getting it up and running for the first.
The first problem I ran into was that when the USB device was connected to the Host (Windows in my case) was the host issues a Reset request. The USB device would reset and clear the interrupt enable flags. I didn't read the literature enough to know this was happening, thus I was never receiving the Set-Up Request Interrupt. It took me quite a while to figure this out.
The second problem I ran into was not handling the Set-Up Request for Set_Configuration properly. I was handling it, but I was not processing the request correctly in that the USB device was not sending an ACK when this Set-Up Request came in. I eventually found this out by using a hardware USB protocol analyzer.
There were other issues that I ran into, but these were the two biggest ones that took me quite a while to figure out. The other issue I had to worry about is big-endian and little-endian, Freescale 9S12 vs USB data format (Intel), respectively.
I ended up building the USB device driver similar to UART device drivers I had done in the past. I have posted the code to this at the following URL.
http://lordhog.wordpress.com/2010/12/13/usb-drive
I tend to use structures a lot, so people may not like them since they are not as portal as using #defines (e.g., MAX3420_SETUP_DATA_AVAIL_INT_REQR 0x20), but I like them since it makes the code more readable for me. If anyone has questions regarding it please feel free to e-mail and I can try to give some insight to it. The book "USB Complete: The Developer's Guide" was helpful, so long as you knew what areas to concentrate on. This was a simple application and only used low-speed USB.
While writing a device driver for any interface (USB, Parallel port, etc...) the code needed to be developed would depend upon whether there is any Operating System(OS), RTOS running on that Processor/Micro controller.
e.g. if thats going to run say WinCE - It will have its own Driver development Kit , and steps to be followed in the device driver development. Same for any other OS like Linux, symbian.
If its going to be a plain firmware code(No OS) which is going to control the processor/microcontroller, then it's a different situation altogether.
So based on either of the above situation u are in, one needs to read & understand:-
1.) The Hardware Specification of the processor/micro controller development board - Register files, ports, memory layout, etc.
2.) USB spec
3.) Couple of pointers i found quickly. Google shud be ur friend!
http://www.lrr.in.tum.de/Par/arch/usb/usbdoc/ - Linux USB device driver
http://www.microsoft.com/technet/archive/wce/support/usbce.mspx
-AD
I've used an earlier edition of USB Complete by Jan Axelson. Indeed very complete.
From the editorial review:
Now in its fourth edition, this developer's guide to the Universal Serial Bus (USB) interface covers all aspects of project development, such as hardware design, device firmware, and host application software.
I'm curious, why did you pick the 9S12? I used it at a previous job, and was not pleased.
It had lousy gcc support so we used Metrowerks
which may have been okay for C, but often generated buggy C++
had a lousy IDE with binary project files!
The 9s12 was also slow, a lot of instructions executed in 5 cycles.
Not very power efficient, either.
no barrel shifter, made operations that are common in embedded code slow
not that cheap.
About the only thing I dislike more is an 8051. I'm using an ARM CortexM3 at my current job, it's better than a 9S12 in every way (faster clock, more work done per clock, less power consumption, cheaper, good gcc support, 32-bit vs. 16-bit).
I don't know which hardware you're planning to use but assuming that's flexible, STMicro offers a line of microcontrollers with USB/SPI support and a library of C-code that can be used with their parts. -- I've used their ARM7 series micros for years with great success.
Here is an excellent site maintained by Jonathan Valvano, a professor at the University of Texas. He teaches four courses over there (three undergraduate, one graduate), all are about using a 9S12 microcontroller. His site contains all the lecture notes, lab manuals, and more importantly, starter files, that he uses for all his classes.
The website looks like it's from the 90's, but just dig around a bit and you should find everything you need.
users.ece.utexas.edu/~valvano/
Consider AVR for your next MCU project because of it's wonderful LUFA and V-USB libraries.
I'm working on a project using the Atmel V71. The processor is very powerful and among lot's of high end connectivity offered on chip is a USB engine that will do device or host modes for 480 Mhz or 48Mhz (not USB 3.0). The tools are free and come with a number of host and device USB example projects with all the USB stack code right there. It supports 10 end points and all the transfers are done via DMA so you have most of the processor horsepower available for other tasks. The Atmel USB stack works without needing an RTOS