I need to send an receive a maximum of 26 Bytes and at any one time @ 2400Baud but many multiple operations in a session. The Rx side will only ever be used in response to the Tx transmissions (response and data). Data put in to a volatile Array.
Question 1 Due to such low speeds would Tx Interrupts be the way to go or polling. I do need to do other things so I'm leaning towards ISRs.
Question 2 If I used Tx ISR's what is the best way to disable the Interrupt when not used - I'm thinking that playing with the UCSRnB register bits. Is this the preferred technique .
Question 3 - I need to write this data to FRAM over SPI (at 8MHz). I don't need specific code for SPI just help on the structure/technique for implementing this in my program. Would the SPI stuff be a separate routine or within main(), do I need to implement this in a ISR, how would I use a standard public C routine etc.
A bit of background I have most of what I need working (apart from 1& 2 above) but not combined or optimised in a program they don't teach you this on YT or in books.