LeafLabs Garden » Topic: Serial Stream ... Hexadecimal to Digital

LeafLabs Garden » Topic: Serial Stream ... Hexadecimal to Digital http://forums.leaflabs.com/topic.php?id=74377 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:13:55 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://forums.leaflabs.com/search.php gbulmer on "Serial Stream ... Hexadecimal to Digital" http://forums.leaflabs.com/topic.php?id=74377#post-105536 Thu, 09 Oct 2014 05:27:55 +0000 gbulmer 105536@http://forums.leaflabs.com/ There are easier ways. The first point is the number can't be completely converted until it is known that all of the number has arrived. A common way to do this is to receive a character that isn't part of the number. For the serial monitor that is newline or carriage return. So parsing character by character doesn't gain much. Secondly it is straightforward to write code which converts from characters to a binary number without assuming much about the number (other than it will fit into an int). Third, it is easier to debug if the whole line of text is collected into an array, and then 'decoded'. It is easy to add a print statement which echos the value read so far, and print statements which show the processing steps. FInally, the character codes for '0' to '9', 'A' to 'F', or 'a' to 'f', are not conveniently arranged to be the value 0 to 9, and 10 to 15. They are ASCII (or the first 127 of UTF-8) codes, and so they need to be converted to the correct binary value. This hasn't been tested, and isn't exactly the way I would do it, however, it might help you: <pre><code>// forum topic 74377 #include <string.h> #include <ctype.h> int inByte; char line[20]; int linePos = 0; const char prefix[] = "PRS "; // End of String, i.e. the 0 byte. const char EOS = 0; // The forum software consumes '\ followed by 0' which breaks code // So this kludge reduces that problem. int hexValue; int nibble; void setup() { Serial1.begin(57600); } void loop() { if (Serial1.available()) { inByte = Serial1.read(); SerialUSB.print(inByte, BYTE); } if (inByte == '\n' || inByte == '\r') { // got a line? line[linePos] = EOS; // reducing horriblness of forum S/W if (strncmp(prefix, line, sizeof(prefix)) == 0) { // matches prefix? linePos = strlen(prefix); // skip over prefix hexValue = 0; while (isxdigit(line[linePos])) { // 0-9, A-Z, a-z? if ('A' <= line[linePos] && line[linePos] <= 'F') { nibble = (line[linePos]-'A')+10; } else if ('a' <= line[linePos] && line[linePos] <= 'z') { nibble = (line[linePos]-'a')+10; } else if ('0' <= line[linePos] && line[linePos] <= '9') { nibble = (line[linePos]-'0'); // Edit: deleted "+10" } hexValue = (hexValue << 4) + nibble; } SerialUSB.print("value of line='"); SerialUSB.print(line); SerialUSB.print("' value of number="); SerialUSB.print(hexValue); SerialUSB.print(" in hex="); SerialUSB.println(hexValue, HEX); } linePos = 0; // get ready for another line } else if (linePos < sizeof(line)-1) { // append to line line[linePos] = inByte; linePos++; } }</code></pre> WARNING: This has been compiled but not tested. ABSimon on "Serial Stream ... Hexadecimal to Digital" http://forums.leaflabs.com/topic.php?id=74377#post-105533 Wed, 08 Oct 2014 10:28:30 +0000 ABSimon 105533@http://forums.leaflabs.com/ Hello, thank you very mutch, but with UART I geht the string character by character, for examlple "1" and "8" and "B" and "3" and "9" and I want to parse it in realtime. I am looking for a function like this int inByte; // Byte read from Serial1 int start; int pressure; void setup() { // Initialize Serial1 Serial1.begin(57600); start = 0; } void loop() { // Read from Serial1, send over USB: if (Serial1.available()) { inByte = Serial1.read(); if (inByte == "P" || inByte == "R" || inByte == "S") { start = 0; } if (start) { if (start == 1) { pressure = inByte * 10000; } if (start == 2) { pressure += inByte * 1000; } if (start == 3) { pressure += inByte * 100; } if (start == 4) { pressure += inByte * 10; } if (start == 4) { pressure += inByte; SerialUSB.println(pressure, DEC); } start++; } if (inByte == " ") { start = 1; } } } Or is there an easyer was to do it? Thank you. Simon nmillan1 on "Serial Stream ... Hexadecimal to Digital" http://forums.leaflabs.com/topic.php?id=74377#post-105531 Mon, 06 Oct 2014 12:43:50 +0000 nmillan1 105531@http://forums.leaflabs.com/ You need to separate the data into two strings before printing it to screen. It seems like each line always starts with a "PRS " (4 characters) so you can experiment with using "string.h" functions such as strcpy() and strtok() to parse it. Save the data before the blank space to one string and the data after to the other. ABSimon on "Serial Stream ... Hexadecimal to Digital" http://forums.leaflabs.com/topic.php?id=74377#post-105530 Mon, 06 Oct 2014 12:34:04 +0000 ABSimon 105530@http://forums.leaflabs.com/ Hello, I have a very simple Script <pre><code>int inByte; void setup() { Serial1.begin(57600); } void loop() { if (Serial1.available()) { inByte = Serial1.read(); SerialUSB.print(inByte, BYTE); } }</code></pre> an now try to parse this result. PRS 18B41 PRS 18B40 PRS 18B41 PRS 18B40 PRS 18B3F PRS 18B42 PRS 18B40 PRS 18B43 PRS 18B3F PRS 18B3C PRS 18B3F PRS 18B3D PRS 18B40 PRS 18B3E PRS 18B3F PRS 18B3D PRS 18B39 PRS 18B3D PRS 18B3E PRS 18B3C PRS 18B3B PRS 18B3C PRS 18B3D PRS 18B3B PRS 18B3A PRS 18B3B PRS 18B3B PRS 18B3D PRS 18B3A PRS 18B39 I need the secound hexadecimal number as a digital number. I think with "inByte = Serial1.read();" I can check each byte, so after "PRS " I have to build a digital number. I have realy no idea... Thank you very Mutch Simon