124 lines
3.2 KiB
C
124 lines
3.2 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define bool int
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#define byte unsigned char
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#define numChars 32
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// Here we are using global variables simply to be compatible with the Arduino program structure
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// This is REALLY bad practice so please don't do it otherwise!
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long int count = 0;
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long int error = 0;
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enum states {state1=1, state2, state3, state4};
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bool channelAState=0;
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bool channelBState=0;
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enum states state;
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char receivedChars[numChars]="00"; // an array to store the received data
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void initialiseEncoderStateMachine();
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void updateEncoderStateMachine();
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enum states get_state();
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int main()
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{
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// Replicates the setup in Arduino
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printf("Enter a pair of characters representing initial states of channels A and B\n");
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scanf("%s",receivedChars);
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channelAState = receivedChars[0]!='0';
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channelBState = receivedChars[1]!='0';
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initialiseEncoderStateMachine();
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printf("State %d, count %ld, error %ld\n", state, count, error);
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printf("Enter a pair of characters representing channels A and B, enter 99 to end\n");
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// Replicates the loop in Arduino
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do
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{
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scanf("%s",receivedChars);
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if (strcmp(receivedChars, "99")==0)
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{
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break;
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}
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channelAState = receivedChars[0]!='0';
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channelBState = receivedChars[1]!='0';
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updateEncoderStateMachine();
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printf("State %d, count %ld, error %ld\n", state, count, error);
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}
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while(1);
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return 0;
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}
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// Could be implemented as a C macro, which would be faster
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// but I've forgotten how to define C macros
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enum states get_state()
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{
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/* If A is 0 and B is 0, system is in State 1
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If A is 1 and B is 0, system is in State 2
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If A is 1 and B is 1, system is in State 3
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If A is 0 and B is 1, system is in State 4 */
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if (channelAState && channelBState) return state3;
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if (channelAState && (!channelBState)) return state2;
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if ((!channelAState) && channelBState) return state4;
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if ((!channelAState) && (!channelBState)) return state1;
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return state1; // silences clang-diagnostic-return-type warning
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}
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void initialiseEncoderStateMachine()
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{
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state = get_state();
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}
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void updateEncoderStateMachine()
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{
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enum states new_state = get_state(); // get new state, don't update state yet so states can be compared
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switch (state)
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{
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case state1:
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// check new state is valid, coming from state1, increment error count if not
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// adjust count as appropriate if new state is valid
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switch (new_state) {
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case state1: break;
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case state2: count++; break;
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case state3: error++; break;
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case state4: count--; break;
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}
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break;
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case state2:
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switch (new_state) {
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case state1: count--; break;
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case state2: break;
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case state3: count++; break;
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case state4: error++; break;
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}
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break;
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case state3:
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switch (new_state) {
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case state1: error++; break;
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case state2: count--; break;
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case state3: break;
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case state4: count++; break;
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}
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break;
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case state4:
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switch (new_state) {
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case state1: count++; break;
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case state2: error++; break;
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case state3: count--; break;
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case state4: break;
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}
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break;
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}
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state = new_state; // set new state
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}
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