revise delay timing #34
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
some LGT8x instructions are faster than original AVR's. especially PUSH/POP/RET/LD/LDD/ST/STD/RJMP take 1 clock, it needs re-calculate delay value. _delay_loop_2() and tunedDelay() added always_inline attribute. This is disadvantage for memory usage but no need to worry about calculating CALL/RET clock cycle. under my brief testing, the result of previous code was 230400bps Rx failed @ 8MHz, TRx failed @ 4MHz 115200bps Rx failed @ 4MHz but now 230400bps TRx failed @ 8MHz, Rx failed @ 4MHz 115200bps TRx failed @ 4MHz anyway 115200bps and higher transfer rate is not recommended for 8MHz and under CPU clock.
there is a bit difference among gcc-7.3.0, gcc-5.4.0 and gcc-4.9.2 but almost same on receiving. so _rx_delay_xxyyzz does not depend by compiler version. on the other hand, _tx_delay value is prepared for gcc-7.0 (and later), and previous compiler.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
for details see (closed) pull request #29
base repository is changed from new-software-serial-timings to master