文件列表:

Cable Tester\defs.inc (1198, 1996-11-21)
Cable Tester\Makefile (433, 1996-11-21)
Cable Tester\receiver.asm (7195, 1996-11-21)
Cable Tester\receiver.hex (926, 1996-11-21)
Cable Tester\sender1.asm (2194, 1996-11-21)
Cable Tester\sender1.hex (300, 1996-11-21)
Cable Tester\tester.fig (17350, 1996-11-21)
Cable Tester\tester.gif (8309, 1996-11-21)
Cable Tester (0, 2008-12-30)

This is the code for a simple cable tester for multipolar cables where the two ends are not in physical proximity; examples include network/phone cables etc. The tester is made of two modules: a sender, and a receiver, both based on a PIC. (C) 1996 Maurizio Fabbri, Fabio Raso, Luigi Rizzo Dipartimento di Ingegneria dell'Informazione via Diotisalvi 2 -- 56126 PISA (ITALY) email: luigi@iet.unipi.it PRINCIPLE OF OPERATION The tester uses N>=2 wires. In turn, each of the wires is used by the sender as a hot (H) wire, while the others are used as return wires. The sender module sweeps cyclically all the wires by sending a different code on each of them (a code is a bit pattern representing the wire index). The resulting pattern on each wire is made of a period of inactivity followed by the transmission of the code. The receiver scans all the wires, waiting for the idle period, and then trying to identify the code. Once all wires are processed, the output can be produced by displaying the connection between wires at the two ends. MORE DETAILS The current version of the tester uses just a PIC on each module, thus limiting to 8 wires. In order for the tester to work, it is necessary that at least two wires are connected in the cable (otherwise, the tester reports wires as disconnected). On the sender, wires are directly connected to the PIC's port B pins. The hot wire is configured as an output, whereas the return wires are configured as inputs and pulled up with an external resistor (about 1KOhm). On the receiver, wires go to port B pins through a current-limiting resistor (5 KOhm). This is to protect inputs and to avoid conflicts when portB is used to display results. The output is reported as a sequence of 2 digits: the first one reports the wire on the receiver, the second one the wire on the sender. For the latter, three special symbols are used to signal that the wire is stuck low, stuck high (or unconnected) or noisy. The testing process is quite fast (and could become faster). Each code is sent as an 8-bit pattern lasting 224us (28us/bit), so a full sweep takes 1.8ms. The receiver needs 1 sweep/wire to make a complete test, so test results are available in about 15ms. SCHEMATICS schematics are in the "tester.gif" file TODO + if wires are connected together, report all the wires in addition to the first one (requires a simple extension to the software - operating time remains the same). + if wires are connected to the receiver side only, report them as connected together (requires a simple extension to the software - operating time increases by a very little amount). + extend the tester to more than 8 wires (requires using external analog multiplexers, e.g. CD4051 1-to-8). The operating time is proportional to N*N, in the case of *** wires it is still about 0.5s + make the tester report results over an RS232 line. A tester for *** requires 1 PIC, eight 8-to-1 mux on each sender/receiver, plus 4 displays on the receiver.

近期下载者：

相关文件：

评论：[我要评论] [举报此文件]

收藏者：