I am after an low level non-HAL USB implementation for an STM32F407 controller

[Pauldg123]

I am after USB OTG CDC (Virtual com port) implementation for STM32F407 controller. The USB device generated via MxCube is working with a set of newer HAL/LL libraries. Unfortunately all the application code is written with older Low Level libraries so the possible solutions are:

A. Appln with older libraries combined with USB running on new libraries (lazy way, short cut. The way I have been working...)
B. Port Appln to newer libraries so everything works together (that's the way you do it but I have limited time)
C. Port USB to older libraries so all works together (that's a fall back and hard to debug plus workarounds)

I have been trying plan A with importing the USB files into the Appln framework and the other way around ( Importing the Appln code into the USB framework (produced by CubeMx application) to avoid spending too much time).

That took a full day with no luck (still 2700 errors), so should I could move on to plan B since that is clearly the way to do it? However I have limited time and resources to do so.
Does any one has a working low level USB implementation for the STM32F4 or any suggestions/ideas?

[Jeroen3]

A. won't work. There are naming conflicts. Tried it, failed.
It might work if one part is compiled to a library. But that will have other problems.

B. Perhaps. Until they change library version again.

C. No.

D. Pull USB into bare metal, remove hal completely.
https://github.com/fcayci/stm32f4-bare-metal/tree/master/projects/usb-vcp-libopencm

[Pauldg123]

Thank you so much, this is really helpful   (Dank je wel!)

Indeed, I tried A for two days and waste all my time because of the myriad of naming collisions.

Fortunately you have (hopefully) a working bare metal USB VCP driver that I was after. Well done and I will try it out first thing tomorrow.

[Jeroen3]

Not mine  . i just googled "stm32f4 usb bare metal". There are some more choices.

[newbrain]

What Jeroen3 said.

But I'd propose also A.2: Use CubeMX with the old libraries.


In the package manager you can still install old Cube SW, and then select it by pointing the code generation to the right place.

[mark03]

I can recommend dmitrystu's libusb_stm32 stack:  https://github.com/dmitrystu/libusb_stm32
Works great.

[newbrain]

The only problem I see is that mixing libraries might become an irreducible mess - OP's project is already built upon the HAL (for good or bad).
E.g.: ISR and Systick handling, as the HAL relies on a 1ms Systick.

I would check if the used HAL version is still available in CubeMX and go from there...

[zzattack]

I've successfully combined this library STM32_XPD with CubeMX/HAL.

[Pauldg123]

hi all, thanks for giving me some leads.

I have looked at a Github repo that does a low level implementation:
https://github.com/RdMaxes/stm32f4_USB_VCP

It does compile with my appln code, so far so good and the appln works as usual.

However when I add the initialize USB driver to my main.c routine,

 

Code: [Select]

USBD_Init(&USB_OTG_dev,USB_OTG_FS_CORE_ID,&USR_desc,&USBD_CDC_cb,&USR_cb);
 I got a compiler error related to instantiation of the USB object.

Code: [Select]

Error[Pe020]: identifier "USB_OTG_dev" is undefined D:\grbl_f405_3\grbl_f405_3\source\main.c 32
In my vector.c interrupt routine, I have stated the object but clearly something is wrong.

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//-----------------------------------------------------------------------------

typedef void (*intfunc)(void);

typedef union
{
  intfunc __fun;
  void* __ptr;
} intvec_elem;
//-----------------------------------------------------------------------------

#ifdef __cplusplus
  extern "C" {
#endif
//-----------------------------------------------------------------------------

extern u32 __intvec_start__;
//-----------------------------------------------------------------------------
// Added for USB driver by Paul
extern USB_OTG_CORE_HANDLE       USB_OTG_dev;
extern uint32_t USBD_OTG_ISR_Handler (USB_OTG_CORE_HANDLE *pdev);
//-----------------------------------------------------------------------------
// Forward declarations
void __iar_program_start(void); // IAR startup code
//-----------------------------------------------------------------------------

#pragma optimize=none
//-----------------------------------------------------------------------------

void reset_handler(void)
{
  SystemInit();

  // Execute IAR startup code and start main()
  __iar_program_start();
}
... etc
//-----------------------------------------------------------------------------
void hardfault_handler(void) etc...

Further down the vector settings...

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  .....
  {default_handler}, // 82 CAN2_SCE
  {OTG_FS_IRQHandler}, // 83 OTG_FS // Added for USB driver Paul OTG_FS_IRQHandler
  {default_handler}, // 84 DMA2_Stream5
  {default_handler}, // 85 DMA2_Stream6 SD-Card
  {default_handler}, // 86 DMA2_Stream7 UART6 Downlink Tx DMA Stream
  {USART6_IRQHandler}, // 87 USART6 UART6 Downlink Rx  USART6_IRQHandler
  .... etc

I believe that USB_OTG_dev need to be assigned with an unique handle id or number so the interrupt can be married to the USB Object... if I make any sense...

Okay any help would be appreciated since I am so close but still not out of the woods. Of course I can still try other repos but with 1 error to solve it might be just a tiny jump to success.

Thx!

[newbrain]

 

Code: [Select]

USBD_Init(&USB_OTG_dev,USB_OTG_FS_CORE_ID,&USR_desc,&USBD_CDC_cb,&USR_cb);
 I got a compiler error related to instantiation of the USB object.

Code: [Select]

Error[Pe020]: identifier "USB_OTG_dev" is undefined D:\grbl_f405_3\grbl_f405_3\source\main.c 32

Well, I think you should believe your compiler.
USB_OTG_dev is never defined, at least in the code you posted.
In the example, I see its declaration as:

Code: [Select]

__ALIGN_BEGIN USB_OTG_CORE_HANDLE  USB_OTG_dev __ALIGN_END;

[Pauldg123]

Hi, it's declaration is in the vector.c code,

Code: [Select]

---

 #ifdef __cplusplus
  extern "C" {
 #endif
//-----------------------------------------------------------------------------

extern u32 __intvec_start__;
//-----------------------------------------------------------------------------
// Added for USB driver by Paul
extern USB_OTG_CORE_HANDLE       USB_OTG_dev;
extern uint32_t USBD_OTG_ISR_Handler (USB_OTG_CORE_HANDLE *pdev);
//----------------------------------------------------------------------------
But that seems not to work properly. I tried to declare it in main too s=with the same result so it must be the syntax

extern USB_OTG_CORE_HANDLE       USB_OTG_dev;

maybe I need to create the handle: USB_OTG_CORE_HANDLE usbdevice_handle;  ?

[newbrain]

I don't exactly know how your code is organized, but it still seems that you are lacking a definition of that variable (= something telling to reserve the space for the variable, and possibly initialize it).
Your

Code: [Select]

extern USB_OTG_CORE_HANDLE       USB_OTG_dev;is only a declaration, the extern storage-class specifier simply tells the compiler that some translation unit (= source file + its includes) in this program must contain a definition of this identifier.

The line I suggested to add to main.c does just that.
If we ignore the "magic" alignment macros (of no interest for this issue):

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USB_OTG_CORE_HANDLE       USB_OTG_dev;is just what is needed for a (tentative) external object definition.

A common practice is to have the declarations in an include file, and the definitions in only one source.

inc.h:

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extern int myvar; /* declaration, makes sure that myvar has external linkage */
src1.c:

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#include "inc.h"
int myvar = 42; /* External object definition, not tentative, as we have also an initializer */

src2.c:

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#include "inc.h"

void func(void)
{
    myvar++;  /* refers to myvar defined in src1.c */
}

References in the C99 standard (draft):

• Chapter 6.2.2: Linkage of identifiers
  tells you that extern declaration will refer to the same object in different translation units.
• Chapter 6.7.1: Storage-class specifiers
  describe how to use extern.
• Chapter 6.9.2: External object definitions
  explains the that one external definition is needed (exactly one if not tentative), and the allowed syntax.

[Pauldg123]

After a rebuild all it simply compiled so I must have had some files not being compiled...

After running the code, the USB port does appear on the device manager but the usb descriptors are missing. I will do some more hunting. Thanks all.