Software » Canbridge

h1. Modes

h2. Unrelated Stubborn

* Send CAN messages as Broadcast messages; fire and forget
* Good enough for sensor values
* Robust code, not much that can fail
* Not good enough for e.g. Flashing firmware on remote device or even scanning nodes.

h2. Related Guaranteed

* Each package need an acknowledge
* Retransmitts are send if acknowledge is missing
* Heavy traffic if nodes are blocking each other.
* Complex code, but ok
* Order may not be guearanteed / optional

h1. Related

h2. Retransmits

* In starting phase there is an auto-tune which requires traffic
* There are at least some CRC errors

h2. h1. Send package

* ringTransmitted.canPush()?
* store essage there
* Send it via RFM69

h2. Receive package

* If type is "Acknowledge"
** find corresponding message
** mark slot as acked/nacked

* If regular message/resend
** If resend: is the package older than the last?, drop it
** is it not last+1? send NACK via RFM69
** fill it in the receive buffer
** directly send acknowledge via RFM69

h2. Loop

* iterate Slots
* If WAITing: is message is older than ??ms, perform an resend
* If ACKed, pop it from the ring. Not the first non-ACKed? Error
* If NACKed, resend it, if there is no WAITing before

h2. Open points

* Acknowledge gets lost; retransmit started
** last-id for every net. Drop message if it matches

* RFM-Class receives messages in ISR as fast as possible. Sending acknowledge is done in the loop.
** Order should be preserved.
** Makes things super slow