With version 0.2 we made the first public release in binary form of the
firmware. This comes together with the merge of the ATUSB driver to the
mainline linux kernel.
DFU files need to have a valid DFU suffix which provides information about the
USB vendor and product ID it should be used for as well as same basic CRC file
integrity checking. The dfu-suffix tool can add this and got added to dfu-utils
in 0.7.
With the Makefile changes we take the original atusb-bin file, make a copy and
add the DFU suffix it before flashing.
This decreases the retrieval time for a frame of 102 bytes from
660 us to 384 us, corresponding to a speed change from about
1.26 Mbps to 2.17 Mbps (102 bytes plus 2 bytes overhead).
queued_rx held a frame in the transceiver's receive buffer until we could
transfer it. This may cause frame loss if a new reception begins.
We now retrieve frames from the transceiver immediately and buffer them
in the MCU.
- mac.c (queued_tx_ack, rx_done, handle_irq): on TX completion, send a
a zero byte on EP 1
- mac.c (handle_irq): don't receive zero-sized frames (they're
malformed anyway), so that size zero can be used to signal TX
completion
This function set isn't really usable for real communication. Its main
purpose is to help with testing the firmware.
- tools/lib/driver.h (struct atrf_driver): added driver functions for
HardMAC access
- tools/include/atrf.h (atrf_rx_mode, atrf_rx, atrf_tx),
tools/lib/atrf.c: functions to enable/disable HardMAC mode and to
send/receive frames
At an interrupt barrier, the host must be able to ensure that no
interrupt generated before reaching the barrier is still pending and
will be delivered after crossing the barrier.
For this, we introduce the following concept:
- interrupts have a serial number. This number is sent to the host
on EP 1 (currently bulk) to signal the interrupt, instead of the
zero byte we used previously.
- the new request ATUSB_SPI_WRITE2_SYNC returns the interrupt
serial number from after the register write (the register write
itself is the interrupt barrier).
- the host can now check if the serial indicated from bulk and the
serial from ATUSB_SPI_WRITE2_SYNC are the same. If yes, interrupts
are synchronized. If not, it has to wait for the interrupt to be
signaled on EP 1.
We should also consider the case that the interrupt serial has gotten
ahead of ATUSB_SPI_WRITE2_SYNC. But that seems to happen rarely. In
any case, it's something for the host driver to worry about, not for
the firmware.
- board.h (irq_serial), board_app.c (irq_serial, INT0_vect): count
the interrupt serial number and return it when signaling the
interrupt
- include/atusb/ep0.h (ATUSB_SPI_WRITE2_SYNC), ep0.c (my_setup):
new request ATUSB_SPI_WRITE2_SYNC that does a register write, then
returns the interrupt serial
