I don't know about the authentic Black Pill from Arduino. But I use one from WeAct and finally got it working with USB wireless keyboard, so I am sharing interesting things I found out here.
Blackpill's USB port was designed for USB device only. It probably has a diode connected to USB's VCC to prevent the device to overload the board's power. If you would like to connect a device, you have to provide power to the device yourself. In my case, I modify a USB cable to add power to the VCC line to feed the device with external 5V.
I connected the USB keyboard like this
Blackpill<==>USB-OTG cable (USB-C to USB-A) <==> my modified cable <==> USB keyboard.
Alternatively, you might build your own USB interface and connect that way so you can correctly feed 5V supply to the device.
==================================================
Additional notes.
==================================================
*You don't have to enable VBUS or SOF in STM32CubeIDE. However the IDE requires you to assign a pin to act as VBUS enable so you just assign a GPIO pin as Output (push-pull) and assign Drive_VBUS_FS as GPIO:Output (under USB_HOST/Platform Settings)
*USB host requires MX_USB_HOST_Process() to be called frequently to get data from USB. If your main loop takes a long time and just to get a USB keyboard working, you might consider adding polling commands into your own keyboard input function. For example:
unit8_t kBin,kBout,kBuffer[16];
In my case, I wrote a simple keyboard buffer input within USBD_HID_EventCallback()
void USBH_HID_EventCallback(USBH_HandleTypeDef *phost){
if(USBH_HID_GetDeviceType(phost) == HID_KEYBOARD){
HID_KEYBD_Info_TypeDef *Keyboard_Info;
Keyboard_Info = USBH_HID_GetKeybdInfo(phost);
uint8_t key = USBH_HID_GetASCIICode(Keyboard_Info);
if(key==0)return;
if(((kBin+1)&0xf)==kBout)return;
kBuffer[kBin]=key;
kBin=(kBin+1)&0xf;
}
}
and I wrote a simple getch() like this:
extern uint8_t getch(char *ch){
for(int i=0;i<10;i++){
MX_USB_HOST_Process();
HAL_Delay(2);
}
if(kBin==kBout) return 0;
*ch = kBuffer[kBout];
kBout = (kBout+1)&0xf;
return 1;
}
In the program, I used:
int ch;
if(getch(&ch)){
...to do...
}
So MX_USB_HOST_Process() will be called when needed, which in this case, waiting for a keystroke.
