bcd7d57c11
Instead of OOCD_SERIAL triggering an attempt to use a specific ftdi based adapter, introduce common target/interface pairs, OOCD_INTERFACE and OOCD_TARGET, and an override via OOCD_FILE allowing full control. Further, attempt to connect to a running openocd instance to flash if possible. This _will not_ work well if you have multiple openocd instances open at once, but that's a rare use case. Examples: OOCD_INTERFACE=stlink-v2 OOCD_TARGET=stm32f0x --> openocd ... -f interface/stlink-v2.cfg -f target/stm32f0x.cfg) OOCD_FILE=board/ek-lm4f120xl.cfg --> openocd ... -f $(OOCD_FILE) (ie, the variable is passed untouched) As part of implementing this, correct variables that were always wrong, and update the openocd flashing commands to use current commands.
README
This example demonstrates the following:
- Using the USB controller
- Setting up a simple usb to serial converter (CDCACM)
File list:
usb_cdcacm.c- implementation of the CDCACM subclassuart.c- implementation of UART peripheralusb_to_serial_cdcacm.c- glue logic between UART and CDCACM deviceusb_to_serial_cdcacm.h- common definitions
Implements a USB-to-serial adapter, compliant to the CDCACM subclass. UART1 is used for the TX/RX lines. Although UART1 also has lines for flow control, they are not used. Instead, the control lines are implemented in software via GPIOA.
The following pinout is used: Tx <- PB1 Rx -> PB0 DCD -> PA2 DSR -> PA3 RI -> PA4 CTS -> PA5 (UNUSED) DTR <- PA6 RTS <- PA7
Note that the CTS pin is unused. The CDCACM specification does not define a way to control this pin, nor does it define a way to switch between flow control mechanisms.
The glue logic in usb_to_serial_cdcacm.c receives requests from both the UART
and CDCACM interface, and forward them to their destination, while also
controlling the LEDs
The green LED is lit as long as either DTR or RTS are high. The red LED is lit while the UART is sending data. The blue LED is lit while data is read from the UART. The red and blue LEDs will only be lit for very short periods of time, thus they may be difficult to notice.
Windows Quirks
On openening the CDCACM port Windows send a SET_LINE_CODING request with the
desired baud rate but without valid databits. To run this example CDDACM device
under Windows you have to return always 1 when a SET_LINE_CODING request is
received. The following code should work:
File: usb_cdcacm.c
Function: cdcacm_control_request()
case USB_CDC_REQ_SET_LINE_CODING:{
struct usb_cdc_line_coding *coding;
if (*len < sizeof(struct usb_cdc_line_coding))
{
return 0;
}
coding = (struct usb_cdc_line_coding *)*buf;
glue_set_line_coding_cb(coding->dwDTERate,
coding->bDataBits,
coding->bParityType,
coding->bCharFormat);
return 1;