Downloaded @KurtE's latest SPI changes and running Buddabrot and graphicsTest.ino while I had a scope on pin 13:
Code:
@600Mhz
w/60Mhz clock ---- scope showed 57.14Mhz
w/40Mhz clock ----- scope showed 40mhz
w/80Mhz clock ----- FAILED
Note: This test was run on a board with a tri-state buffer chip on the MISO line. Tested at 816Mhz CPU and got same results.
Repeated 80Mhz SPI Clock on a board with no-MISO tri-state buffer on MISO:
Code:
80Mhz ---- PASSED: scope 83Mhz
Probes are really rated to go higher:
@90 Mhz
Code:
Benchmark Time (microseconds)
Screen fill 77323
Text 5744
Lines 36367
Horiz/Vert Lines 6837
Rectangles (outline) 4471
Rectangles (filled) 159244
Circles (filled) 31817
Circles (outline) 32787
Triangles (outline) 8354
Triangles (filled) 59390
Rounded rects (outline) 12918
Rounded rects (filled) 179058
Hit key to continue
Done!
Rectangles (filled) FB 19006
Hit key to continue
Done!
Rounded rects (filled) FB 21046
Hit key to continue
Done!
@110Mhz
Code:
Benchmark Time (microseconds)
Screen fill 77323
Text 5744
Lines 36368
Horiz/Vert Lines 6837
Rectangles (outline) 4472
Rectangles (filled) 159246
Circles (filled) 31817
Circles (outline) 32766
Triangles (outline) 8354
Triangles (filled) 59390
Rounded rects (outline) 12921
Rounded rects (filled) 179055
Hit key to continue
Done!
Rectangles (filled) FB 19024
Hit key to continue
Done!
Rounded rects (filled) FB 21051
Hit key to continue
Done!