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Converting Mouse RS232 (PC/2) into Kempston Mouse
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First of all, you need to make sure that the optocouplers of the given
The mouse is working properly by connecting it to the PC. If that's not the case then
It is possible that the modification will be somewhat more difficult than
previously assumed.
Now you need to carefully remove the microcircuit from the board,
marking the power paths connected to it (8th ground, 16th
+5v), quartz, capacitor, unnecessary resistors. Let's just leave
buttons, optocouplers, LEDs with resistors in their circuit.
Let's check which power pole the common wire is connected to
buttons Let's say it connects to the plus. Then the microcircuit
Place DD1 (TL1) with the 7th foot in the hole where there was
The 13th leg of the removed MC, therefore the 14th leg falls into
8th. We will then insert one of the re-
resistors. Actually, after removing everything unnecessary, we should have
be enough holes to install all the necessary
details.Example of a mouse board after replacing the MC (top view):
+----------------------------------+
| |
| _______ _______ _______|
| |
| . . . . . . . . |
| ____________1 |
| ____DD1______ |
| . . . . . . . . |
| 1. |
| 1 2 3+---+ +-+. |
| . . .| +--------------+2.| | |
| +---+ | | |. |
| +---+ |3.| | |
| . . | +--+ +--+
+------+
Let's remove one of the resistors in the LED circuit and replace it
for the one we need, the second one usually does not need to be deleted - it has
very small resistance that can be neglected, but
It’s better to put a jumper instead. Let's cut everything off
tracks from optocouplers and MC (exceptpower circuits, if they coincide
with our circuit), and connect them according to the new circuit (see below).
+5v +5v
| | R1...R4 - 5...bkom
| +------------+ R5 - 100...150
| | ||+---+ | DD1 1561 TL1
| | 3|||1 | |
| | +---+ | | +-+
-VD1| | Y | | +13| |
V | +---+ | +12| +11---PHASE Y
- | | +-|
| +-__---__------1| |
| R1 | R3 +-2| +3----COUNT Y
| +-----| +-|
| R2 | R4 +-6| |
| +-__---__------5| +4----PHASE X
- | | +-|
V | +---+ | +-8| |
-VD2| | X | | +-9| +10---COUNT X
| | +---+ | | +-+
| | 3|||1 | | S1/
| | ||+---+ | +---/ -----LEFT_R5 +-----------+ | S2/
| | +---/ -----MID
| +5v | S3/
| +---/ -----RIGHT
--- |
---
Pinout of a standard Kempston Mouse connector:
1. +5v
2.COUNT Y
3.PHASE Y
4.COUNT X
5.PHASE X
6. LEFT button
7. MIDDLE button
8. RIGHT button
9.Gnd
P.S. The main thing is not to be afraid: “What if it doesn’t work? =8-()”. I
Many times I just mixed up a couple of other wires ;)
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