Communication
with a PS/2 mouse You are the visitor n.
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Communication
with a PS/2 mouse You are the visitor n.
Best view with 1024x768 |
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As explained in the article Host - PS/2 mouse hardware communication on this site, to test the protocol needed to communicate with a PS/2 mouse I have interfaced it with a properly programmed PIC 16F84. Pay attention: PS/2 devices are different from serial mice, concerning both communication protocol and electrical levels; in PS/2 mice levels used for supply and data exchange are 0 and +5V, in serial mice we instead find the RS-232 levels, +12V and -12V. This article is concerning a PS/2 mouse. The PIC too must receive a +5V supply. In particular, common (or ground) pins of PIC and PS/2 mouse must be connected together; the same for +5V pins. To connect the mouse and the microcontroller together I suggest a flying PS/2 plug, to which you can connect the four needed wires. Such wires can then be carried to a prototype board and connected on it to the wires coming from the proper PIC's pins. To operate the PIC I have used the version previous to the one described in the article PIC 16F84 F.F. Evaluation Board on this site. For connections refer to the article about Host - PS/2 mouse hardware communication, to the PS/2 connector pin-out and to the first lines of the assembler list below. If in this way the mouse shouldn't show any sign of life, connect two pull-up resistors between data and clock and +5V supply (that, I repeat, must be the same for the microcontroller and the mouse). Proper values are around 3-10 KOhm. Take care to connections, to avoid unpleasant damages to devices! Instead of damaging a PIC or a mouse, if you are not really sure of acting correctly you can write me. This page has been moved to the new site If you wish please click on this link
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