https://sourceforge.net/p/ut61/wiki/protocol/Recent changes to protocolenThu, 10 Oct 2013 21:17:32 -0000https://sourceforge.net/p/ut61/wiki/protocol/<div class="markdown_content"><pre>--- v1 +++ v2 @@ -47,7 +47,7 @@ Message format -------------- -0: [+-] +0: +/- 1-4: Digits (but see below) 5: Space 6: Precision </pre> </div>Örjan WennbomThu, 10 Oct 2013 21:17:32 -0000https://sourceforge.netddd513ceec0859c53f04dc7d5096d75dde71228fhttps://sourceforge.net/p/ut61/wiki/protocol/<div class="markdown_content"><h1 id="analysis-of-ut61-communications">Analysis of UT61 communications</h1> <p>Everything described in this document is implemented in m_ut61.h, so<br /> that file can be referred to as a working example.</p> <h2 id="usb-cable">USB cable</h2> <p>Start logging:<br /> (This is a HID Set Report request)<br /> CT 21 09 00 03 00 00 00 00</p> <p>To read from the device listen to interrupt transfers from endpoint 82.<br /> There you'll find 8-byte blobs roughly every 10 ms. I have identified two<br /> types (They are likely described in the USB HID spec), identified by their<br /> first byte:</p> <p>f0 - No data available, the rest of the bytes are 0<br /> f1 - Here, have a character! Second byte is the character.</p> <p>If you assemble all the contiguos characters, you will end up with a<br /> 14-character message as described below.</p> <h2 id="rs232-cable">RS232 cable</h2> <p>The RS232 cable uses 2400 baud with 8 bit characters, no parity and 1<br /> stop bit. To activate it, the RTS line needs to be cleared and the DTR<br /> line set.</p> <p>As the data packets all end with CRLF, you can use line-oriented reading<br /> from the port.</p> <p>This is how the Windows application sets things up:<br /> SET_BAUD_RATE 2400<br /> CLR_RTS<br /> SET_DTR<br /> SET_LINE_CONTROL 8n1<br /> SET_CHAR EOF:0 ERR:0 BRK:0 EVT:0 XON:11 XOFF:13<br /> SET_HANDFLOW Shake:1 Replace:0 XonLimit:512 XoffLimit:1<br /> PURGE TXABORT RXABORT TXCLEAR RXCLEAR<br /> SET_QUEUE_SIZE InSize: 2048 OutSize: 2048<br /> SET_TIMEOUTS RI:1 RM:0 RC:1 WM:0 WC:0</p> <h2 id="message-format">Message format</h2> <p>0: <span>[+-]</span><br /> 1-4: Digits (but see below)<br /> 5: Space<br /> 6: Precision<br /> 7-8: Flags<br /> 9: Prefix and special flags<br /> 10: Unit<br /> 11: Relative measurement integer<br /> 12-13: CRLF</p> <p>The four digits are the measured value with the decimal point removed.<br /> However, if the meter is overloading, the value "?0:?" is reported.</p> <p>The precision is a single ASCII digit with the following meaning:<br /> 0: There is no decimal point<br /> 4: There is one decimal digit<br /> 1: There are three decimal digits<br /> 2: There are two decimal digits</p> <p>The seventh and eighth bytes are a bit field. I have observed these bits:<br /> 0x0001 Bar graph visibility<br /> 0x0002 Data hold<br /> 0x0004 Rel<br /> 0x0008 AC<br /> 0x0010 DC<br /> 0x0020 Autorange<br /> 0x0200 Nano prefix<br /> 0x1000 Min<br /> 0x2000 Max</p> <p>Byte 9 consists of two 4-bit fields, prefix and special flags.<br /> The prefix has the following meaning:<br /> 0x00 No prefix (or nano prefix, as per above)<br /> 0x10 Mega (M)<br /> 0x20 Kilo (k)<br /> 0x40 Milli (m)<br /> 0x80 Micro (µ)</p> <p>The special flags are:<br /> 0x00 Nothing special<br /> 0x02 %<br /> 0x04 Diode<br /> 0x08 Buzzer</p> <p>The unit byte reads as follows:<br /> 0x00 Percent<br /> 0x04 Fahrad<br /> 0x08 Hz<br /> 0x20 Ohm<br /> 0x40 Ampere<br /> 0x80 Volt</p> <p>Byte 11 contains a 7-bit signed integer corresponding to the measured<br /> value in 64ths of the current range.</p></div>Örjan WennbomThu, 10 Oct 2013 21:16:51 -0000https://sourceforge.neta82fa2a637d85704f742a118be0b3d9f48ed0bc1