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Diffstat (limited to 'tests/usb-serial-rs485/README')
| -rw-r--r-- | tests/usb-serial-rs485/README | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/tests/usb-serial-rs485/README b/tests/usb-serial-rs485/README new file mode 100644 index 0000000..e3d4948 --- /dev/null +++ b/tests/usb-serial-rs485/README @@ -0,0 +1,21 @@ +------------------------------------------------------------------------------ +README +------------------------------------------------------------------------------ + +This implements a USB CDC-ACM device, connected to USART2 (PA2-tx/PA3-rx) +An interrupt driven tx ring buffer is used for usb->serial, and a similar +interrupt driven rx ring buffer is used for serial->usb. +Baud rates from 2400-460800 are tested with zmodem transfers in both directions. + +Parity not yet finished, and baudrates below 1200 need fiddling with clock prescalers. +When it's finished, rs485 support should be available via the TC interrupt. + +A GPIO is toggled around USART transmissions to control an RS485 line +transceiver, following ST's app note. The RS485 driver enable line is, +by default, just the onboard red LEDs. + +The orange/blue LEDs indicate tx/rx activity, but especially for the rx line, +you won't really see it without heavy data rates. + +This example is heavily based on the existing usb_cdcacm and usart demos. + |