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Commit Graph

17 Commits

Author SHA1 Message Date
Werner Almesberger
f862a82a2d ubb-la/ubb-la.c: new option -F freq_MHz to select "unsafe" frequencies 2013-01-28 21:06:00 -03:00
Werner Almesberger
85bda4c41d ubb-la/ubb-la.c (frequency): adapt use of mmcclk for API change 2013-01-28 21:05:01 -03:00
Werner Almesberger
14b7a9cdee ubb-la/ubb-la.c (xfers): instead of waiting for event, use hand-optimized delay loop
The gap is just as long as when waiting for an event but the "start bit"
on DAT0 has vanished completely:

1       3       gap     2       0       1       3
------- ------- ------- ------- ------- ------- -------
53              77                      16      146
66              79                      1       146
81              79                              132
96              79                              117
2013-01-28 16:43:29 -03:00
Werner Almesberger
18a822b845 ubb-la/ubb-la.c (xfers): wait for END_CMD_RES instead of DATA_FIFO_EMPTY
This seems to make no difference for the gap but the "start bit" (DAT0
pulled low) seem to get 1-2 samples shorter:

1       3       gap     2       0       1       3
------- ------- ------- ------- ------- ------- -------
146             77      9                       60
147     13      79      9                       45
145     28      79      10                      29
146     43      79      9                       15
2013-01-28 16:43:23 -03:00
Werner Almesberger
4ffd61093b ubb-la/ubb-la.c (do_bufs): don't skip 122 nibbled (for evaluation)
A series of measurements of

A# ./ubb-patgen  -f 41kHz 1
A# ./ubb-patgen  -f 41kHz -c
B# ./ubb-la -f 12 -n 10

yielded these results:

1       3       gap     2       0       1       3
------- ------- ------- ------- ------- ------- -------
106             77      11                      98
120             78      11                      83
134             79      11                      68
        3       79      11                      53
        18      78      11                      39
        33      78      11                      24
        47      79      11                      9
        62      79      5       6       140     147
        77      79              11      125     147

Where for example the last entry corresponds to

...1{146}3{77}
0{11}1{125}3{147}...

Since this looks as if DAT1 was 1 for 77 samples before the first capture
ended, was 0 throughout the pulling low of DAT0 (11 cycles), stayed low
for another 125 cycles, and then went high for the 146.29 nominal
half-period, we thus get a gap length of 2*146-77-11-125 = 79
2013-01-27 18:23:38 -03:00
Werner Almesberger
37a219b0b9 ubb-la/ubb-la.c: option -n N to enter experimental multi-buffer mode (WIP) 2013-01-26 23:25:17 -03:00
Werner Almesberger
13f34170de ubb-la/ubb-la.c (do_buf): physmem_xlat doesn't need a cast
We inherited the cast from ubb-patgen where the buffer was "const" and thus
had to be cast for the the non-const argument of physmem_xlat. We never
needed a cast in ubb-la, though.

Since physmem_xlat now uses "const" as well, the cast is even doubly
superfluous.
2013-01-26 20:49:09 -03:00
Werner Almesberger
8316bc0070 ubb-la/ubb-la.c (do_buf): move pretty-printing to new function print_samples 2013-01-26 20:01:32 -03:00
Werner Almesberger
4ceee66c79 ubb-la/ubb-la.c (INITIAL_SKIP): describe how the value was obtained 2013-01-26 19:55:44 -03:00
Werner Almesberger
09de2454ef ubb-la/Makefile (CFLAGS): use more specific -O9 -fno-tree-cselim
Third time lucky, I hope. -fno-tree-cselim is much more specific than
disabling all optimization and results in a considerably less severe
performance reduction (about 30-40% of -O0).
2013-01-25 19:49:20 -03:00
Werner Almesberger
07026753de ubb-la/README: brief description of ubb-la 2013-01-24 20:04:40 -03:00
Werner Almesberger
4ce6866767 ubb-la/ubb-la.c (do_buf): skip over the first 122 samples
They are from the setup process and therefore invalid (DAT0) and/or out
of sync (DAT0-3) with the rest of the samples.
2013-01-24 20:00:59 -03:00
Werner Almesberger
62284fb78e ubb-la/ubb-la.c: add command-line options, keyboard abort 2013-01-24 18:26:34 -03:00
Werner Almesberger
bac21bf8cb ubb-la/Makefile (CFLAGS): even -O1 isn't safe; use -O0 instead
While -O1 gets rid of the unexpected read in the simple code of a synthetic
test, it's still there in the more complex environment we have in ubb-la.c
Turning off optimization completely seems to do the trick.
2013-01-24 17:35:52 -03:00
Werner Almesberger
e1eea4fa86 ubb-la/Makefile (CFLAGS): -O9 is currently unsafe; use -O1
Higher optimizations can cause the generation of code that unexpectedly
does the equivalent of  PDFUNS = PDFUNS;

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56098
2013-01-24 15:31:59 -03:00
Werner Almesberger
2c5b3625a7 ubb-la/: data capture via UBB and MSC+DMA (WIP) 2013-01-23 11:54:23 -03:00
Werner Almesberger
d4c1f5666c ubb-la/hw/: proof-of-concept passive LA adapter board
Note that the pull-ups on DAT1 through DAT3 and the pull-whichever-way on
DAT0 are likely to get in the way of any real-life use. But it's good enough
for exploring the system's characteristics and limitations.
2013-01-23 11:52:11 -03:00