rbsexton / stm32l073

Application framework for Forth on STM32L073

stm32l073

Application framework for Forth on STM32L073

Appendices

Useful STM Documentation

• UM1749 User Manual Description of STM32L0 HAL and Low Layer drivers ( dm00113898-description-of-stm32l0-hal-and-low-layer-drivers-stmicroelectronics)
• UM1734 STM32Cube(TM) USB device library ( dm00108129-stm32cube-usb-device-library-stmicroelectronics )

USB Notes.

USB Device IP has to operate independently of software support.

OUT/Host to Device Flow

• Host sends OUT Packet, Plus a data packet.
• Device ACKs the Packet if its expecting it and has room.
• Device accepts the data.
• Stack does the callback to CDC_Itf_Receive()
• Firmware calls HAL_PCD_EP_Receive() to set up the next transfer.

IN/Device to Host Flow

• Host sends IN Packet
• Device Sends data if it has it.
• USB Stack calls
• Firmware calls HAL_PCD_EP_Receive() to set up the next transfer.

USBD_CDC_ReceivePacket() is the fn that you call to tell the USB stack that the device can accept more data.

Memory Usage

Baseline after first compile

text	   data	    bss	    dec	    hex	filename
22836	   1464	   8268	  32568	   7f38	exe/supervisor.out

After Ripping out USART code

text	   data	    bss	    dec	    hex	filename
18172	   1464	   8068	  27704	   6c38	exe/supervisor.out