Date:2010-11-03 14:30:34 (8 years 10 months ago)
Author:Werner Almesberger
Commit:c91658e1edad7ac97ef1a0a4edf1c16490d3603a
Message:cntr/README update: name clarification and bugs list.

- cntr/README: change the name from "Arbitrary-precision counter" to
"Arbitrary-precision frequency counter"
- cntr/README: added list of known hardware issues
Files: cntr/README (2 diffs)

Change Details

cntr/README
1Arbitrary-precision counter
2===========================
1Arbitrary-precision frequency counter
2=====================================
33
44Theory of operation
55-------------------
66
7The arbitrary-precision counter counts clock cycles of a frequency
8source that is assumed to be free from drift. It compares the count
9with the host's system clock. If the system clock is synchronized with
10an accurate NTP reference, measurements with arbitrarily high accuracy
11can be obtained.
7The arbitrary-precision frequency counter counts clock cycles of a
8frequency source that is assumed to be free from drift. It compares the
9count with the host's system clock. If the system clock is synchronized
10with an accurate NTP reference, measurements with arbitrarily high
11accuracy can be obtained.
1212
1313In practice, this is limited by the the frequency source's drift and
1414the time one is willing to wait. If NTP maintains the system time
...... 
6464
6565To update the firmware, run
6666cntr -r && sleep 1 && dfu-util -d 0x20b7:0xcb72 -D cntr.bin
67
68
69Known issues (hardware)
70-----------------------
71
72- the MMCX connector is hard to solder because of its large thermal
73  capacitance and surface
74- the lateral pads of the MMCX connector could be wider
75- manufacturing tolerances can push the USB connector a bit inside
76  the board, making its signal pins overshoot the pads
77- the ground fill under the LED causes a secondary cathode contact
78  (which is harmless on this case)

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