28f92cce2b
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. Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
43 lines
1.5 KiB
Plaintext
43 lines
1.5 KiB
Plaintext
------------------------------------------------------------------------------
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README
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------------------------------------------------------------------------------
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This example demonstrates the following:
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* Using the USB controller
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* Setting up a simple usb to serial converter (CDCACM)
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File list:
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* usb_cdcacm.c - implementation of the CDCACM subclass
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* uart.c - implementation of UART peripheral
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* usb_to_serial_cdcacm.c - glue logic between UART and CDCACM device
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* usb_to_serial_cdcacm.h - common definitions
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Implements a USB-to-serial adapter, compliant to the CDCACM subclass. UART1 is
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used for the TX/RX lines. Although UART1 also has lines for flow control, they
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are not used. Instead, the control lines are implemented in software via GPIOA.
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The following pinout is used:
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Tx <- PB1
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Rx -> PB0
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DCD -> PA2
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DSR -> PA3
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RI -> PA4
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CTS -> PA5 (UNUSED)
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DTR <- PA6
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RTS <- PA7
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Note that the CTS pin is unused. The CDCACM specification does not define a way
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to control this pin, nor does it define a way to switch between flow control
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mechanisms.
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The glue logic in usb_to_serial_cdcacm.c receives requests from both the UART
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and CDCACM interface, and forward them to their destination, while also
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controlling the LEDs
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The green LED is lit as long as either DTR or RTS are high.
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The red LED is lit while the UART is sending data.
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The blue LED is lit while data is read from the UART.
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The red and blue LEDs will only be lit for very short periods of time, thus they
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may be difficult to notice.
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