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prod/doc/analysis.html: more material on checking the supply voltages

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Werner Almesberger 2011-05-19 13:55:03 -03:00
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<H2>Supply voltages</H2> <H2>Supply voltages</H2>
The transceiver has three voltage domains:
<UL>
<LI>The supply and I/O voltage, which is nominally 3.3 V in
<B>atben</B> and <B>atusb</B>,
<LI>the digital (core) supply, which is nominally 1.8 V, and
<LI>the analog (RF) supply, which is nominally 1.8 V.
</UL>
<BR>
On <B>atusb</B>, there is also the USB voltage domain at nominally 5.0 V.
<P>
Voltages should be tested in the following order: USB, then I/O, then
digital, and finally analog. The table below gives the permissible
ranges. Any voltages outside of these ranges indicate a problem.
<P>
<TABLE>
<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>I/O<TD>3.3 V<TD>3.0 V<TD>3.6 V
<TR><TD>Digital<TD>1.8 V<TD>1.7 V<TD>1.9 V
<TR><TD>Analog<TD>1.8 V<TD>1.7 V<TD>1.9 V
</TABLE>
<P>
<H3>Measurement setup</H3>
The measurements should be performed either with a digital multimeter.
To enable all voltage domains, put the transceiver in receive mode:
<PRE>
atrf-txrx
</PRE>
or
<PRE>
atrf-txrx -d net:ben
</PRE>
Exit with Ctrl-C.
<P>
To produce periodic transmissions in addition to enabling all voltage
domains, use
<PRE>
atrf-txrx -p 3 -E 0
</PRE>
or
<PRE>
atrf-txrx -d net:ben -p 3 -E 0
</PRE>
Again, exit with Ctrl-C. Note that the transmissions may disturb nearby
equipment operating in the 2.4 GHz band, such as 802.11 networks. This
can be prevented by shorting the antenna to ground.
<P>
In case the board does not accept commands, only the USB and I/O voltage
can be checked. If they are correct, proceed with checking the clock.
<!-- ---------------------------------------------------------------------- -->
<H3>Measurement points on atben</H3>
<!-- ---------------------------------------------------------------------- -->
<H3>Measurement points on atusb</H3>
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