├── README.md
├── mcs-12085.cpp
└── mcs-12085.h


/README.md:
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1 | Arduino interface to MCS-12085/12086 Optical Mouse Sensor
2 | 
3 | Connect SDIO/SCLK to pins defined in mcs-12085.cpp and then call
4 | mcs12085_dx() and mcs12085_dy() to read distance mouse has moved since
5 | last call.


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/mcs-12085.cpp:
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  1 | // mcs-12085.cpp
  2 | //
  3 | // Copyright (c) 2012 John Graham-Cumming
  4 | //
  5 | // Code to interface to MCS-12085 Optical Mouse Chip
  6 | 
  7 | #include "mcs-12085.h"
  8 | 
  9 | // The digital pins that are connected to SCLK and SDIO on the sensor
 10 | 
 11 | int clk_pin = 4;
 12 | int dat_pin = 7;
 13 | 
 14 | // The time of a clock pulse. This will be used twice to make the clock
 15 | // signal: cycle us low and then cycle us high
 16 | int cycle = 25;
 17 | 
 18 | // mcs12085_init: set up the pins for the clock and data
 19 | void mcs12085_init() 
 20 | {
 21 |   // When not being clocked the clock pin needs to be high
 22 |   
 23 |   pinMode(clk_pin, OUTPUT);
 24 |   digitalWrite(clk_pin, HIGH);
 25 | 
 26 |   pinMode(dat_pin, OUTPUT);
 27 |   digitalWrite(dat_pin, LOW);
 28 | }
 29 | 
 30 | // mcs12085_tick: perform a single clock tick of 25us low
 31 | void mcs12085_tick()
 32 | {
 33 |   digitalWrite(clk_pin, LOW);
 34 |   delayMicroseconds(cycle);
 35 |   digitalWrite(clk_pin, HIGH);  
 36 | }
 37 | 
 38 | // mcs12085_tock: finish the clock pulse by waiting during the high period
 39 | void mcs12085_tock()
 40 | {
 41 |   delayMicroseconds(cycle);
 42 | }
 43 | 
 44 | // mcs12085_read_bit: read a single bit from the chip by creating a clock
 45 | // pulse and reading the value returned
 46 | int mcs12085_read_bit()
 47 | {
 48 |   mcs12085_tick();
 49 |   
 50 |   int r = (digitalRead(dat_pin) == HIGH);
 51 |   
 52 |   mcs12085_tock();
 53 |   return r;
 54 | }
 55 | 
 56 | // mcs12085_read_byte: Reads 8 bits from the sensor MSB first
 57 | byte mcs12085_read_byte()
 58 | {
 59 |   int bits = 8;
 60 |   byte value = 0x80;
 61 |   byte b = 0;
 62 |   
 63 |   while (bits > 0) {
 64 |     if ( mcs12085_read_bit() ) {
 65 |       b |= value;
 66 |     }
 67 |     
 68 |     value >>= 1;
 69 |     --bits;
 70 |   }
 71 |   
 72 |   pinMode(dat_pin, OUTPUT);
 73 |   digitalWrite(dat_pin, LOW);
 74 |   
 75 |   return b;
 76 | }  
 77 |                        
 78 | // mcs12085_write_bit: write a single bit to the chip by creating a clock
 79 | // pulse and writing the value
 80 | void mcs12085_write_bit(byte b)    // 1 or 0
 81 | {
 82 |   // Set the data pin value ready for the write and then clock
 83 |   
 84 |   if ( b ) {
 85 |     digitalWrite(dat_pin, HIGH);
 86 |   } else {
 87 |     digitalWrite(dat_pin, LOW);
 88 |   }
 89 |   
 90 |   mcs12085_tick();
 91 |   mcs12085_tock();
 92 |   digitalWrite(dat_pin, LOW);
 93 | }
 94 | 
 95 | // mcs12086_write_byte: write a byte to the sensor MSB first
 96 | void mcs12085_write_byte(byte w)      // Number to get the bits from
 97 | {  
 98 |   int bits = 8;
 99 |   
100 |   while ( bits > 0 ) {
101 |     mcs12085_write_bit(w & 0x80);
102 |     w <<= 1;
103 |     --bits;
104 |   }
105 |   
106 |   pinMode(dat_pin, INPUT);
107 | }
108 | 
109 | // mcs12085_wr_pause: pause between a write and a read to the sensor
110 | void mcs12085_wr_pause()
111 | {
112 |   delayMicroseconds(100);
113 | }
114 | 
115 | // mcs12085_rw_pause: pause between a read and a write to the sensor
116 | void mcs12085_rw_pause()
117 | {
118 |   delayMicroseconds(250);
119 | }
120 | 
121 | // mcs12085_convert: converts a byte into a signed 8-bit int
122 | int mcs12085_convert(byte b) 
123 | {
124 |   if ( b < 128 ) {
125 |      return int(b);
126 |   } else {
127 |      return -(int(b ^ 0xFF) + 1);
128 |   }
129 | }
130 | 
131 | // mcs12085_dx: read the change in X position since last read
132 | int mcs12085_dx() 
133 | {
134 |   mcs12085_write_byte(0x02); // 0x02 = Read DX Register
135 |   mcs12085_wr_pause();
136 |   int i = mcs12085_convert(mcs12085_read_byte());
137 |   mcs12085_rw_pause();
138 |   return i;
139 | }
140 | 
141 | // mcs12085_dy: read the change in Y position since last read
142 | int mcs12085_dy()
143 | {
144 |   mcs12085_write_byte(0x03); // 0x03 = Read DY Register
145 |   mcs12085_wr_pause();
146 |   int i = mcs12085_convert(mcs12085_read_byte());
147 |   mcs12085_rw_pause();
148 |   return i;
149 | }
150 | 
151 | 
152 | 
153 | 
154 | 
155 | 
156 | 


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/mcs-12085.h:
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 1 | // Turtley - Logo Turtle controller
 2 | //
 3 | // Copyright (c) 2012 John Graham-Cumming
 4 | //
 5 | // Code to interface to MCS-12085 Optical Mouse Chip
 6 | 
 7 | #ifndef INCLUDED_MCS12085
 8 | #define INCLUDED_MCS12085 1
 9 | 
10 | #include <Arduino.h>
11 | 
12 | void mcs12085_init();
13 | int mcs12085_dx();
14 | int mcs12085_dy();
15 | 
16 | #endif // INCLUDED_MCS12085
17 | 
18 | 
19 | 
20 | 
21 | 
22 | 


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