PIC32MX: Encoder Motor Control - Revision history

Andrew Long: /* Associated Circuitry */

2010-04-16T04:44:05Z

Associated Circuitry

Andrew Long: /* Quadrature Encoder Example */

2010-04-16T04:43:40Z

Quadrature Encoder Example

Andrew Long: /* Available Pins */

2010-04-16T04:39:50Z

Available Pins

Andrew Long: /* Associated Circuitry */

2009-08-13T17:15:14Z

Associated Circuitry

Andrew Long: /* Associated Circuitry */

2009-08-13T16:36:29Z

Associated Circuitry

Andrew Long at 16:10, 13 August 2009

2009-08-13T16:10:23Z

Andrew Long: /* Sample Code */

2009-08-13T16:09:16Z

Sample Code

Andrew Long: New page: ==Available Pins== The PIC32MX460F512L has 5 available external timer / counter pins denoted TXCK on the pin list, where x is from 1 to 5. Unfortunately, the PIC32MX440F512H has only 1 av...

2009-08-13T16:08:53Z

New page: ==Available Pins== The PIC32MX460F512L has 5 available external timer / counter pins denoted TXCK on the pin list, where x is from 1 to 5. Unfortunately, the PIC32MX440F512H has only 1 av...

New page

==Available Pins==
The PIC32MX460F512L has 5 available external timer / counter pins denoted TXCK on the pin list, where x is from 1 to 5.
Unfortunately, the PIC32MX440F512H has only 1 available external counter (T1CK), so this cannot be used for quadrature encoder.
<br><br>

==Quadrature Encoder Example==
This section details how to set up quadrature encoder with the PIC32MX460F512L and the LS7083.

===Sample Code===

First include header files with definitions for generic type definitions, compiler, and for specific PIC. Also include the plib header file.

#include "GenericTypeDefs.h"
#include "Compiler.h"
#include "HardwareProfile.h"
#include <plib.h>

NOTE THAT BECAUSE WE USE THE BOOTLOADER, NO CONFIGURATION IS NECESSARY. THE BOOTLOADER PROJECT ACTUALLY CONTROLS ALL OF OUR CONFIG BITS.

Define the system frequency
#define SYS_FREQ (80000000L)

Define global variables for counting
signed int bigcount = 0; // set encoder value initially to zero, it can go + or -
// 32 bit number
short count0, count1; // 16 bit number
short last0 = 0, last1 = 0; // 16 bit number

Begin main function
int main(void)
{

Configure the proper PB frequency and the number of wait states
SYSTEMConfigPerformance(SYS_FREQ);

Initialize Timer1 and Timer2 as external clocks and periods (PR1, PR2)
OpenTimer1( T1_ON | T1_PS_1_1 | T1_SOURCE_EXT, 0xFFFF);
OpenTimer2( T2_ON | T2_PS_1_1 | T2_SOURCE_EXT, 0xFFFF);

main loop
while (1)
{
count0 = ReadTimer1(); // in your routine this must be done at least every 32000
// encoder counts to avoid rollover ambiguity
count1 = ReadTimer2();

bigcount += count0 - last0; // add on the recent up-counts, since the last time

if (count0 < last0)
{
bigcount += 65536; // count0 only increments, so if it got lower
//it must have rolled over
}

last0 = count0;

bigcount -= count1 - last1; // we're not worrying about rollover of the 32 bit bigcount total

if (count1 < last1)
{
bigcount -= 65536;
}

last1 = count1;

Put Code to Display Here
I put the above code in the Communicate Via USB Code and added the following lines:

sprintf (USB_Out_Buffer, "Encoder Count = %d!\r\n", bigcount);
if(mUSBUSARTIsTxTrfReady())
{
putrsUSBUSART(USB_Out_Buffer);
}

end the main function
return 0;
}

@@ Line 80: / Line 80: @@
 This Circuit is based off the HEDS5500 encoder, LS7083 quadrature, and PIC32MX460F512L.
+[[Media:Quad_Encoder_PIC32_Circuit.pdf]]
-[[Image:Quad_Encoder_PIC32.jpg]]

← Older revision		Revision as of 17:15, 13 August 2009
Line 80:		Line 80:

	This Circuit is based off the HEDS5500 encoder, LS7083 quadrature, and PIC32MX460F512L.		This Circuit is based off the HEDS5500 encoder, LS7083 quadrature, and PIC32MX460F512L.

			[[Image:Quad_Encoder_PIC32.jpg]]

← Older revision		Revision as of 16:36, 13 August 2009
Line 78:		Line 78:

	==Associated Circuitry==		==Associated Circuitry==

			This Circuit is based off the HEDS5500 encoder, LS7083 quadrature, and PIC32MX460F512L.

@@ Line 76: / Line 76: @@
    return 0;
    }
+==Associated Circuitry==

@@ Line 9: / Line 9: @@
 ===Sample Code===
+ /*
-First include header files with definitions for generic type definitions, compiler, and for specific PIC. Also include the plib header file.
+ QuadratureHard.c
-   #include "GenericTypeDefs.h"
+ The PIC32MX460F512L has 5 available external timer / counter pins denoted TXCK on the pin list,
-   #include "Compiler.h"
+ where x is from 1 to 5. Unfortunately, the PIC32MX440F512H has only 1 available external counter (T1CK),
-   #include "HardwareProfile.h"
+ so this PIC cannot be used for quadrature encoder. The NU32 board uses PIC32MX460F512L.
-   #include <plib.h>
+ This code is based on the QuadratureHard.c for the 8-bit PICS.
-NOTE THAT BECAUSE WE USE THE BOOTLOADER, NO CONFIGURATION IS NECESSARY. THE BOOTLOADER PROJECT ACTUALLY CONTROLS ALL OF OUR CONFIG BITS.
+ Quadrature based on Hardware requires two timers to count up-counts and down-counts.
-Define the system frequency
+ PWM uses Timer 2 or Timer 3, therefore, we are going to use Timer 4 and Timer 5 for this code.
-   #define SYS_FREQ 				(80000000L)
+ Timer 4 is T4CK/RC3 and Timer 5 is SDI1/T5CK/RC4.
-Define global variables for counting
+ LS7083 chip decodes quadrature A&B signals into up&down pulses for these two timers
-    signed int bigcount = 0; 	// set encoder value initially to zero, it can go + or -
+ The software version doesn't use up timers but this hardware version is arbitrarily fast
-                                // 32 bit number
+ */
-    short count0, count1; 		// 16 bit number
-    short last0 = 0, last1 = 0; // 16 bit number
+  #include "HardwareProfile.h"
-Begin main function
+  signed int bigcount = 0; 	// set encoder value initially to zero, it can go + or -
-   int main(void)
+  						 	// 32 bit number
-   {
+  short count0, count1; 		// 16 bit number
+  short last0 = 0, last1 = 0; // 16 bit number
-Configure the proper PB frequency and the number of wait states
-   SYSTEMConfigPerformance(SYS_FREQ);
+  int main(void) {
-Initialize Timer1 and Timer2 as external clocks and periods (PR1, PR2)
+  	// Configure the system performance
-   OpenTimer1( T1_ON | T1_PS_1_1 | T1_SOURCE_EXT, 0xFFFF);
+ 	SYSTEMConfigPerformance(SYS_FREQ);
-   OpenTimer2( T2_ON | T2_PS_1_1 | T2_SOURCE_EXT, 0xFFFF);
+ 	mInitAllLEDs();
-main loop
-   while (1)
-   {
+ 	// Must enable glocal interrupts - in this case, we are using multi-vector mode
-      count0 = ReadTimer1();  // in your routine this must be done at least every 32000
+     INTEnableSystemMultiVectoredInt();
-                              // encoder counts to avoid rollover ambiguity
-      count1 = ReadTimer2();
+      // init Timer4 and Timer5 mode and periods (PR4, PR5)
+ 	OpenTimer4( T4_ON | T4_PS_1_1 | T4_SOURCE_EXT, 0xFFFF);
-      bigcount += count0 - last0; // add on the recent up-counts, since the last time
+ 	OpenTimer5( T5_ON | T5_PS_1_1 | T5_SOURCE_EXT, 0xFFFF);
-      if (count0 < last0)
+ 	while (1) {
-      {
+ 		count0 = ReadTimer4();  // in your routine this must be done at least every 32000
-         bigcount += 65536; 		// count0 only increments, so if it got lower
+ 								// encoder counts to avoid rollover ambiguity
-                                        //it must have rolled over
+ 		count1 = ReadTimer5();
-      }
+ 		bigcount += count0 - last0; // add on the recent up-counts, since the last time
-      last0 = count0;
+ 		if (count0 < last0)
-      bigcount -= count1 - last1; // we're not worrying about rollover of the 32 bit bigcount total
+ 		{
+ 			bigcount += 65536; 		// count0 only increments, so if it got lower
-      if (count1 < last1)
+ 	 					   		//it must have rolled over
-      {
+ 		}
-          bigcount -= 65536;
-      }
+ 		last0 = count0;
-      last1 = count1;
+ 		bigcount -= count1 - last1; // we're not worrying about rollover of the 32 bit bigcount total
-Put Code to Display Here.
+ 		if (count1 < last1)
-I put the above code in the Communicate Via USB Code and added the following lines:
+ 		{
+ 			bigcount -= 65536;
-   sprintf (USB_Out_Buffer, "Encoder Count = %d!\r\n", bigcount);
+ 		}
-   if(mUSBUSARTIsTxTrfReady())
-   {
+ 		last1 = count1;
-   putrsUSBUSART(USB_Out_Buffer);
-   }
+                 // Put other code here to display (RS232 works nice)
+ 		}
-end the main function
+ }
-   return 0;
-   }
 ==Associated Circuitry==

@@ Line 1: / Line 1: @@
 ==Available Pins==
 The PIC32MX460F512L has 5 available external timer / counter pins denoted TXCK on the pin list, where x is from 1 to 5.
-Unfortunately, the PIC32MX440F512H has only 1 available external counter (T1CK), so this cannot be used for quadrature encoder.
+Unfortunately, the PIC32MX440F512H has only 1 available external counter (T1CK), so this cannot be used for quadrature encoder using the external counter pins.
 <br><br>