TM4C129XNCZAD: Bit band uDMA

Hi Charles,

As the poster suggests - "bit-banding" appears to offer an, "eased & high speed means" to toggle one (or several) GPIO.

Yet - as w/most considerations w/in tech - are you aware of any "weaknesses/trade-offs" which arise w/"use of bit-band?" (kindly exclude the set-up/config. code) I recall a past client being "excited" by bit-band - and later, "not so much" - and cannot (yet) find the detail.

Thank you Charles - both for the effort you put in here - and for any detail you may provide re: bit-band "trade-off."

Hi cb1,
I can think of some weaknesses. One is a lot of wasted buffer space. Let's say the 8-bit bitstream is to be transmitted. Since each peripheral bit is mapped to a 32-bit address, this will mean the source memory needs to be configured for 32-bit size. The source buffer to hold the bit stream will have 31 out 32 bits wasted since only one bit will be used. The second thing is the control of the baudrate of the bitstream. Perhaps a timer can be use to control the baudrate. But the bitstream can still be interrupted by other higher priority channels. This needs to be taken into account in the application. Is some type of checksum or parity bits to be part of the bitstream? I agree this is not as simple as it sounds. It needs to be finely tune to make it work. The poster did not give detail as to the external component receiving the bitstream and what is the protocol envisioned between the two.

Excellent Charles - thank you - much appreciated.

Perhaps the "lesson learned" is, "Beware - when (only) the advantages of methods are listed - and (only) the passage of time will (or may) reveal (grave) weaknesses!

Caveat (user)