diff options
Diffstat (limited to 'usb-serial-rs485/README')
| -rw-r--r-- | usb-serial-rs485/README | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/usb-serial-rs485/README b/usb-serial-rs485/README new file mode 100644 index 0000000..0e5b2cd --- /dev/null +++ b/usb-serial-rs485/README @@ -0,0 +1,33 @@ +------------------------------------------------------------------------------ +README +------------------------------------------------------------------------------ + +current status: +f1: frootloop3 gets corrupt data in rx path, _after_ serial rx, +but the usb in packets (wireshark) show the corruption. (LA on serial lines is clean) +f4: frootloop3 tests clean +=> suspect libopecm3 usb bug? + +frootloop3: github.com/karlp/frootloop3 + + + +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. + + +KARL - check https://github.com/dhylands/libopencm3-usb-serial/blob/master/usb.c to see if it passes the same tests or not |