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Tiva™ ARM® C Series Microcontrollers Forum
When and why should I use LM4F CAN Tx FIFOs?
The LM4F CAN Tx FIFO example just sets up eight messages and sends them out all at once. Are Tx FIFOs only for the special case of wanting a series of messages to be transmitted in a given order. What if the message addresses have random values so that bus priority is in question? Does the FIFO over ride the standard bus priority? Is a Tx FIFO useful in handling random sets of messages being sent from different program functions such that messages are not lost?
I am writing a CAN driver that uses a barrel queue in front of the hardware. The user asks for a message to be sent, it is put on the barrel queue and timers pop messages off of the barrel queus such that the bus avoids 100% utization - something that can foul a system. I have found it almost impossible to overdrive just a single MOB. So using multiple MOBs is really a plan B for heavy Tx traffic. I assume some user will come up with code that will over drive the CAN driver.
So is a Tx FIFO useful/applicable in this case? -or-
Should I just allocate, say 8, MOBs for Tx messages. Then when I pop a message off of the barrel queue, I just search from the bottom up through the Tx MOBs and place in the first free MOB?
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