qi-hardware/ben-wpan
1
0
Fork 0
mirror of git://projects.qi-hardware.com/ben-wpan.git synced 2024-12-23 18:36:47 +02:00
Code

prod/doc/analysis.html: added borders to tables; use −

Browse Source
This commit is contained in:
Werner Almesberger 2011-05-19 14:46:53 -03:00
parent 926ed26188
commit f52fbe1f6f
1 changed files with 11 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
prod/doc/analysis.html
View File

@ -29,7 +29,7 @@ Voltages should be tested in the following order: USB, then I/O, then
digital, and finally analog. The table below gives the permissible digital, and finally analog. The table below gives the permissible
ranges. Any voltages outside of these ranges indicate a problem. ranges. Any voltages outside of these ranges indicate a problem.
<P> <P>
<TABLE> <TABLE frame="border" cellpadding="2">
<TR><TH>Domain<TH>Nominal<TH>Minimum<TH>Maximum <TR><TH>Domain<TH>Nominal<TH>Minimum<TH>Maximum
<TR><TD>USB<TD>5.0 V<TD>4.5 V<TD>5.25 V <TR><TD>USB<TD>5.0 V<TD>4.5 V<TD>5.25 V
<TR><TD>I/O<TD>3.3 V<TD>3.0 V<TD>3.6 V <TR><TD>I/O<TD>3.3 V<TD>3.0 V<TD>3.6 V
@ -90,12 +90,12 @@ operation. Anomalies are easy to detect with even a low-cost oscilloscope
and pinpoint specific problems and help to select further analysis steps. and pinpoint specific problems and help to select further analysis steps.
<P> <P>
The crystal used in <B>atben</B> and <B>atusb</B> has a nominal tolerance The crystal used in <B>atben</B> and <B>atusb</B> has a nominal tolerance
of +/- 15 ppm at 22-28 C. Low-cost oscilloscopes typically have a timing of +/&minus; 15 ppm at 22-28 C. Low-cost oscilloscopes typically have a timing
accuracy of accuracy of
+/- 100 ppm, which means that only major excursions can be detected by +/&minus; 100 ppm, which means that only major excursions can be detected by
measuring the clock output with such an instrument. Full-speed USB only measuring the clock output with such an instrument. Full-speed USB only
requires an accuracy of +/- 2500 ppm. requires an accuracy of +/&minus; 2500 ppm.
We can therefore consider all results within a range of +/- 1000 ppm as We can therefore consider all results within a range of +/&minus; 1000 ppm as
sufficient, and perform more precise measurements by other means. This sufficient, and perform more precise measurements by other means. This
applies to <B>atben</B> as well as to <B>atusb</B>. applies to <B>atben</B> as well as to <B>atusb</B>.
<P> <P>
@ -114,7 +114,7 @@ atrf-txrx -d net:ben -C 1
This configures <B>atben</B> as a promiscuous receiver. The reception This configures <B>atben</B> as a promiscuous receiver. The reception
of any IEEE 802.15.4 frame or pressing Ctrl-C will terminate the command. of any IEEE 802.15.4 frame or pressing Ctrl-C will terminate the command.
<P> <P>
<TABLE> <TABLE frame="border" cellpadding="2">
<TR><TH align="left">Clock<TH align="left">Action <TR><TH align="left">Clock<TH align="left">Action
<TR><TD>0 Hz<TD>Check voltages; check that the clock is enabled; <TR><TD>0 Hz<TD>Check voltages; check that the clock is enabled;
check for shorts around crystal; check connectivity of crystal check for shorts around crystal; check connectivity of crystal
@ -136,7 +136,7 @@ the transceiver generates a 1 MHz clock. When the microcontrolled comes out
of reset, it raises the transceiver's clock output to 8 MHz and then of reset, it raises the transceiver's clock output to 8 MHz and then
enables USB. enables USB.
<P> <P>
<TABLE> <TABLE frame="border" cellpadding="2">
<TR><TH align="left">Clock<TH align="left">Action <TR><TH align="left">Clock<TH align="left">Action
<TR><TD>0 Hz<TD>Check voltages; check for shorts around crystal; check <TR><TD>0 Hz<TD>Check voltages; check for shorts around crystal; check
connectivity of crystal connectivity of crystal
@ -154,7 +154,7 @@ enables USB.
<H3>Precision measurements</H3> <H3>Precision measurements</H3>
The clock frequency of <B>atben</B> can be measured with an accuracy The clock frequency of <B>atben</B> can be measured with an accuracy
of about +/- 100 ppm using the program <B>atrf-xtal</B>. <B>atrf-xtal</B> of about +/&minus; 100 ppm using the program <B>atrf-xtal</B>. <B>atrf-xtal</B>
runs directly on the Ben and measures the duration of packet transmissions. runs directly on the Ben and measures the duration of packet transmissions.
The transmission time depends on the bit clock which is in turn derived The transmission time depends on the bit clock which is in turn derived
from the oscillator. from the oscillator.
@ -169,10 +169,10 @@ The number reported is the number of poll loops the CPU counted. This
value should be compared to a reference count obtained with a known to value should be compared to a reference count obtained with a known to
be good <B>atben</B> board and the same Ben at a comparable temperature. be good <B>atben</B> board and the same Ben at a comparable temperature.
<P> <P>
<TABLE> <TABLE frame="border" cellpadding="2">
<TR><TH align="left">Difference<TH align="left">Action <TR><TH align="left">Difference<TH align="left">Action
<TR><TD>&gt; +/- 50 ppm<TD>Correct operation <TR><TD>&gt; +/&minus; 50 ppm<TD>Correct operation
<TR><TD>&lt; -80 ppm<TD>Check soldering of capacitors; <TR><TD>&lt; &minus;80 ppm<TD>Check soldering of capacitors;
check for contamination around crystal check for contamination around crystal
<TR><TD>&gt; +120 ppm<TD>idem <TR><TD>&gt; +120 ppm<TD>idem
<TR><TD>Other<TD>Divergence can be compensated by adjusting trim value <TR><TD>Other<TD>Divergence can be compensated by adjusting trim value