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| glossary:glossary_h [2019/09/05 19:14] – added text for Hexadecimal or Hex entry tgerbic | glossary:glossary_h [2019/11/12 01:47] – [Hexadecimal or Hex] Bob Vetterlein |
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| In information technology, telecommunications, and related fields, handshaking is an automated process of negotiation that dynamically sets parameters of a communications channel established between two entities before normal communication over the channel begins. It follows the physical establishment of the channel and precedes normal information transfer. | In information technology, telecommunications, and related fields, handshaking is an automated process of negotiation that dynamically sets parameters of a communications channel established between two entities before normal communication over the channel begins. It follows the physical establishment of the channel and precedes normal information transfer. |
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| | ===== Happening ===== |
| | A term devised, and introduced in the documentation for Universal CANMIO, for an event that is internal to the module to distinguish it from an external event (on the bus). |
| | For instance, say input 1 changes from high to low, in early modules of the CBUS range this would simply produce an ON event with EN (Event Number) of 1, in the Universal code for the CANMIO it produces a 'Happening' with a value that indicates input 1 ON. Through the configuration process this may be mapped to produce that same event or something entirely different. |
| ===== HASL ===== | ===== HASL ===== |
| [[https://en.wikipedia.org/wiki/Hot_air_solder_leveling|Hot Air Solder Leveling]]\\ HASL = hot air solder levelling - the bare copper of the etched PCB would soon oxidise and refuse to take solder, so a thin layer of "something" is added to make the shelf life longer. The standard HASL provided by Chinese manufacturers is leaded solder. More expensive options are lead free solder, organic solderable varnish stuff, nickel, or gold flash. | [[https://en.wikipedia.org/wiki/Hot_air_solder_leveling|Hot Air Solder Leveling]]\\ HASL = hot air solder levelling - the bare copper of the etched PCB would soon oxidise and refuse to take solder, so a thin layer of "something" is added to make the shelf life longer. The standard HASL provided by Chinese manufacturers is leaded solder. More expensive options are lead free solder, organic solderable varnish stuff, nickel, or gold flash. |
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| When a hex number is used in a program or written text, it is usually proceeded by some characters to identify which number system you are using. Consider the number 100. In decimal this is one hundred. In binary this is four. In hex it is two hundred fifty six (0001 0000 0000). If you mean 256 then some programmers and programs would put a letter combination such as '0x', '0h' or # before the number (0x100) or a letter such as H or h after (100h). In the MERG forum you will generally see hexadecimal 100 shown as 0x100. | When a hex number is used in a program or written text, it is usually proceeded by some characters to identify which number system you are using. Consider the number 100. In decimal this is one hundred. In binary this is four. In hex it is two hundred fifty six (0001 0000 0000). If you mean 256 then some programmers and programs would put a letter combination such as '0x', '0h' or # before the number (0x100) or a letter such as H or h after (100h). In the MERG forum you will generally see hexadecimal 100 shown as 0x100. |
| | =====ASCII Hex===== |
| | When sending numeric information over a serial link such as RS232 or RS485 it is not possible to send it as raw binary data as some of the possible 256 byte values have special meaning and are used to control the information flow, for an explanation of this see [[glossary_a#ascii|ASCII]]. Instead each data byte is split into two hexadecimal digits and transmitted as text. For example the value zero, which would be 8 zero bits is transmitted as '00' that is <0x30><0x30>, value 255 which would be 8 one bits becomes 'FF' that is <0x46><0x46>. |
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| ===== High ===== | ===== High ===== |
