Lightweight 8051 compatible CPU
Djnz_dir seems not working. I my case, i load register B with decimal 10 value and do a loop:
mov B,#10 loop: djnz b,loop
First djnz put B register to decimal 255 value and jump ? Same loop with R0 instead of B works fine.
Best Regards.
Type your text here
Bug found in state djnz_dir_0: signal 'direct_addressing' is not asserted.
As a consequence, the IRAM/SFR bus timing is enough for the IRAM access but not for the SFR access.
As of revision 14 the logic for decoding signal 'direct_addressing' has been fixed and the changes have been tested in the simulation test bench and on the DE-1 board with the dhrystone demo.
This bug slipped past the test bench: 'DJNZ dir' was only tested with an IRAM address. The test bench has been fixed too and now tries DJNZ with an SFR too (SFR B).