Turn USB power off/on with BeagleBone Black kernel >= 3.8 - usb

I need to:
turn off -> sleep some seconds -> turn on the USB power of beaglebone black
to be able to hardware-reset a device that is connected to USB (Huawei E220 Modem)
Already tried soft-reset (with unbind/bind and with authorize 0/1), but software reset is not enough to make the device to work well again; the device has some weird bug, that is triggered by a long-time usage (after a few days connected).
Many answers were found using /sys/debug/omap_mux, but this device does not exist anymore in new kernels.
Since this question took a pair of days to get a workable answer, I decided to post it here, with the answer, so it may be useful for others.

Thanks to my friend Cleiton Bueno http://cleitonbueno.wordpress.com/ that found this solution for me:
prerequisites:
apt-get install devmem2
Code that solved the problem:
devmem2 0x47401c60 b 0x00
sleep 1
echo "usb1" > /sys/bus/usb/drivers/usb/unbind
sleep 20
echo "usb1" > /sys/bus/usb/drivers/usb/bind
sleep 1
devmem2 0x47401c60 b 0x01
The "devmem2" command is responsible to direct access GPIO3_13 of the beaglebone, that controls the IC that powers on/off the USB port.
The "unbind/bind" commands are responsible to tell the usb driver to "rescan" the port after the power.

Related

Can I poll my USB HID device without first sending a command

I was able to make a working HID USB stack on my "StartUSB for PIC" board for the 18F2550 microcontroller. I based it on one of the MLA libraries, which was made for the 18F45K50 (MLA 2018_11_26, hid_custom, picdem_fs_usb_k50.x), but I converted it to work with the 18F2550 (there might have been easier ways, but only learned to work with PIC about 1 month ago). On the host side, I'm using LibUsbDotNet (also here, there might be easier ways - the documentation on this library really sucks) on a Windows 10 machine.
I'm using the HID class, full speed, and all seems to work. Although, I get some random errors on the host PC (see below), but doing one close/re-open cycle on the host side when getting the error is kind of solving it. Dirty, but it works. So I kind of ignore this now.
Win32Error:Win32Error:GetOverlappedResult Ep 0x01
995:The I/O operation has been aborted because of either a thread exit or an application request.
I'm not an expert on USB (yet). But all examples I'm seeing are based on 1) you send first a command to the device and 2) then you retrieve the answer from the device. I did some performance tests, and see that this indeed shows that I can do about 500 cycles/second. I think that is correct, because each cycle, sending command and retrieving answer, each takes 1 msec.
But do I really need to send a command? Can't I just keep reading endlessly, and when the device has somthing to say, it does send the data in an IN transaction, and when not it ignores which creates a timeout on the host side. That would mean that I can poll at 1000 cycles/second? Unfortunately, I have tried it by changing my implementation on the PIC, but I get very weird results. I think I have issues with suspend mode. That brings me to another question - how can I make the device get out of suspend mode (means that not the host, but the device should be triggering this event). I have searched the MLA library for command such as "wakeup", "resume", ... but couldn't find anything.
So, to summarize, 2 questions:
Conceptual: Can I send data from device to host without being requested for it by a command from the host?
For PIC experts: How can I have a device trigger for a wakeup from suspend mode?
And indeed, the answer is Yes on the first question.
In the meantime, I found another link on the web that contains a Visual Studio C# implementation of a USB library including all the source files.
If you're interested, this is the link
This C# host implementation works as a charm. Without sending a command to the device, I get notified immediately if a button is pressed. Great!
It also proofs that my earlier device implementation based on the original MicroChip MLA, is 100% correct. I stress tested the implementation by sending a "toggle LED command" as fast as I could, and I reach 1000 commands/second. Again great!
I think that LibUsbDotNet isn't that perfect after all. As I wrote above, I get rather unstable communication (Win32Error). But with this implementation, I don't get a single error, even after running for half an hour # 1000 commands/second.
So for me, case closed.

Not able to program STM32 MCU using JTAG interface

MCU : STM32L496
JFlash version: v6.32i
We are facing the "Connection to target under reset failed" issue, when we try to program the board with STM32 MCU.
We were programming the board before with no issues. This error started appearing suddenly and now we are not able to program the board. When we scoped the reset pin of the MCU, the reset pin is going low when we click the connect button in the JFlash and clearly the board is resetting (We can see the firmware functionality restarting).
We tried the following:
Tied the BOOT0 pin to VDD and tried booting to the system memory and then tried programming. But this doesn't made any difference.
Tried always pulling down the reset pin to GND while trying to flash.
We have ensured that there are no issues with the track leading to the JTAG interface of the MCU.
Could you please help to resolve this situation?
Is there any possibility that the firmware currently running in the MCU could prevent the flashing and lock the device?
STM32L4 has a feature called Read-out Protection (RDP). See section 1.1 of AN4758. If your firmware application sets (intentionally or accidentally) the RDP level to 1 or 2 in the "option bytes" memory area then the SWD/JTAG port is disabled from accessing flash memory (read, write, and erase).
If the RDP is level 0 or 1 then you should be able to read the option byte memory area. If RDP is level 1 then you should be able to set it back to level 0. The flash memory will be erased when setting RDP back to level 0 but the SWD/JTAG port will get re-enabled. If the RDP level is 2 then I believe there is no way to reset it.
This is a common problem with STM32 SWD interface. For successful programming you should not power your custom board/ other hardware with the ST link power, instead you should make the GND connection common and supply from external source. And if you are using ST link only for programming and not for debugging then you should use the STM32 bootloader(easier).

stm32f3 'USER USB' not detected

I'm working on stm32f3 discovery board. For my current project I planned on coding a simple UART program on the board, I happened to read somewhere on the internet that to use the board for UART communication with PC the 'USER USB' has to be used.
My questions are the following
Firstly when i connect my board to PC using the 'USER USB'. The PC refuses to recognize the board.(F.Y.I- OS used is windows 7 64bit). This problem persists even after I update the driver! How to resolve this?
Is the "Connecting USER USB" part correct? because I can't see any RS232 chip on board
Should I use an add on board?
P.S I've installed all the necessary drivers from ST website and works flawlessly while using 'ST-Link interface' part of the board
I started working with the STM32F3 disco a few weeks ago. The user USB thing is a bit tricky.
To get it clear: The board has 2 USB ports.
One mostly for programming and debugging. It connected to a second ST chip which works as programming adapter.
The seconds (called USER USB) is connected to the STM32F303 chips you program
So what you can do is to configure your STM32 to implement a CDC over USB. With the windows driver installed (automatic or from ST, depends on OS version) you should get a virtual com port in your device manager. If you don't have the driver, you also get a device labeled as virtual com port but with a yellow exclamation mark.
So if I get you question right, this is what you're trying to do? Then yes, "Connecting USER USB" is correct. No, you don't need an extension board.
How to resolve that? It depends:
Do you already see the device in your device manager as communication device or serial interface or something? Then only the CDC driver from ST is missing.
Or do you get an "Unknown Device" in your device manager? That is what I experienced.
In STM32CubeMX you need to enable the USB device (Peripehrals->USB)
In STM32CubeMX you need to select the USB stack (MiddleWares->USB_DEVICE->Communication Device Class)
Generate the code. If you are using HSI as clock source CubeMX will generate a error message you can ignore for now. For a real product you should use an external clock.
Note that there is a bug in CubeMX version 4.20. The code generator generates code which may not work if you select HSE as clock input source. Even if you go back to HSI, the error remains.
Compile an run the code. You maybe need to reset the board removing BOTH USB plugs
Windows should detect the board now.
Extra problem: The board is ... well. Tricky. If you only plug in the USER USB to your PC, it should work but Windows may also inform you that you have an UNKNOWN DEVICE because enumeration has failed.
Remove the plug again. Now, first plug in the other, ST-LINK USB to power on the board. Wait 1-2 seconds. Now plug in the USER USB. There seems to be a startup problem. Only using the USER USB for power supply and CDC seems to run in a race condition between boot and USB and USB enumeration fails. First powering the board and then plugging in removes this race condition (at least at my board)
Now Windows should enumerate the device and offer you a virtual com port. Actually you should get two of them: One "ST... STLink Virtual COM Port" and one "ST... Virtual COM Port". The seconds one is the one you are looking for.
I hope that was the answer on the question you had.
Thanks for the post, had the same issue, here is what I added
Approach: Turn-off USB lines programmatically by changing input to output, forcing it to zero and reenable them after around 1 second
Also used power-off and on from ST USB Libs
// Force Re-Enumeration by the USB Host
//
int aux_retrigger_usb()
{
GPIO_InitTypeDef GPIO_InitStructure;
// ST USB Function
PowerOff();
// Program Pin 12 USB_DP from Input to Output
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
// Set USB_DP to 0
GPIOA->BRR |= GPIO_Pin_12 ;
// Wait for for minimum 32* 50msec , 1,6 secs
while(tim3_cnt%32!=0) ; while(tim3_cnt%32!=31) ;
// ST USB Functions
PowerOn();
USB_Init();
Virtual_Com_Port_Reset() ;
// Program Pin 12 USB_DP from Output to input
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
return 1 ;
}
So basically to avoid the power on race condition, the ports may be programmed
first to outputs and then released after 1 second.
I'm also struggling with the STM32F302. The USB is not recognized by the HUB Down stream port, and therefore does not appear in a device manager on PC(HUB's upstream port is connected to PC).
So, I made a deep search after I checked all the HW and SW.
It appears that 1.5Kohm resistor should be added on a DP, as F302 does not have the embedded one.
My design does not have neither, so hopefully, it will solve the issue tomorrow, so I have a hope for tonight)
You can read AN4879 by ST - the place I found these directions.

Read Data Across USB Port

I'm playing around with an old Trackball I purchased from Sparkfun. My trackball powers on, but it doesn't actually work. All the lights flash, and it indicates that I've left and right clicked, but the mouse on my screen does nothing.
I want to monitor the input values of the trackball across a USB port so I can track down the problem. I've looked for code I can run on Netbeans, but came up empty handed.
Please advise
You didn't specified what OS are you using. You need dedicated driver for this device. In case of Linux you would need to write your own driver for the kernel. But first you need to have specification of protocol which this device is using over usb and also usb protocol itself. It is quite sophisticated task to do...
In case of Windows there are some programs for dumping transmission between usb host (PC) and device (trackball), but at the moment I can't give you any name of such program. In case of Linux you can dump the transmission using tcpdump or wireshark commands.

AT command sent to modem from microcontroller is ignored

Please help, I spent hours trying to rootcause the problem.
Setup: MSP430 (F5529 microcontroller), HW UART (USCI_A0) and modem connected (uBlox Leon G100). I am sure the USCI_A0 port works well because if I connect it via USB-to-RS232 to the PC I can see the correct traffic.
A simple
uart_puts(UART_MODEM, "AT+CPWROFF\r");
shall put AT+CPWROFF to the modem. And it probably does but modem does not power off. If I simply connect modem to PC and type "AT+CPWROFF" finished by Enter then the modem powers off.
I also confirmed on the PC console that the "\r" works well - it just returns the carriage, correctly. Tried "\n\r", does not work either. Checked in the modem settings for S3 character and it's 013 (CR or \r).
I have no idea what is wrong. PC-to-modem works well (I can power off the modem), MSP430-to-PC works ok (I can see that the microconroller really puts AT+CPWROFF\r on the UART), but MSP430-to-modem does not work.
I can determine if the modem is turned on or off by looking at the current consumed.
Please, any hints?
OK, issue solved. If you take a look at the detected baudrate on the links I sent, you will notice that with PC the exact baudrate was 9585 (which is 0.14% of sync difference) while with the MCU it is 7862 (which is 2.73% of sync difference). I switched to 4MHz crystal and now have approx 0.23% out of sync. It's really wondering that the DCO gives so unstable clock.