Differences

This shows you the differences between two versions of the page.

--- pic32mx270f256b [2019/04/25 11:46]
sausage created
+++ pic32mx270f256b [2021/12/14 12:07] (current)
sausage Updated missing details. New code.
@@ Line 1: / Line 1: @@
 ====== Minimum setup for a PIC32MX270F256B on a Breadboard + PICkit3 ======
-After discovering that my PIC32MX170F256B did not sport a USB module, I then purchased a PIC32MX270F256B which did have one.
+My first experiments with PIC Microcontrollers was on the PIC32MX170F256B. But after discovering that there was no USB module on that controller, I then purchased a PIC32MX270F256B which did have one.
 This article serves as a reminder for the minimum setup for this microcontroller.
@@ Line 10: / Line 10: @@
 {{ :pic32mx270f256b-pins.png?nolink |}}
+Here is the overall layout on the breadboard:
+{{ :pic32mx270f256b-breadboard-pickit3-overview.jpg?direct&400 |}}
 Note the following pins on the Microcontroller:
@@ Line 24: / Line 28: @@
   * Pin 2 (RA0) to the positive side of an LED. Negative side of the LED to a 10 Ohm resistor. Then to GND.
   * Pin 3 (RA1) to the positive side of an LED. Negative side of the LED to a 10 Ohm resistor. Then to GND.
 On both the Power and Ground rails on the breadboard, add a 0.1uf capacitor each.
-Also between Pin 20 (CAP) and Pin 9 (VSS) add a 0.01uf capacitor.
+Also between Pin 20 (CAP) and Pin 19 (VSS) add a 0.01uf capacitor.
-Add a 10k pull up? resistor from Pin 1 (MCLR) to Power. MCLR is Master Clear or Reset.
+Add a 10k pull up resistor from Pin 1 (MCLR) to Power. MCLR is Master Clear or Reset.
-That should be the minimum required to test the Microcontroller.
+That should be the minimum required to test the microcontroller.
-You can also get a diagram of the recommended setup on page 28 of the PIC32MX270F256B Datasheet, Figure 2-1.
+{{ :pic32mx270f256b-breadboard-components.jpg?nolink |}}
+You can also get a diagram of the recommended setup on [[https://docs-apac.rs-online.com/webdocs/1385/0900766b8138548d.pdf#G3.1116201|page 28 of the PIC32MX270F256B Datasheet]], Figure 2-1.
@@ Line 42: / Line 47: @@
 Attach a USB cable between the PICkit3 and the computer's USB port.
-Load MPLABX IPE and go to Advanced Settings.
+  - Load MPLABX IPE and go to Advanced Settings.
-Choose Family: 32-bit MCUs
+  - Choose Family: 32-bit MCUs
-Choose Device: PIC32MX270F256B
+  - Choose Device: PIC32MX270F256B
-Under Power: Ensure 3.3V is chosen.
+  - Under Power: Ensure 3.3V is chosen.
-ICSP Options: Check the "Power Target Circuit from Tool"
+  - ICSP Options: Check the "Power Target Circuit from Tool"
-Back in Operate, click on "Read" to see if PICkit3 can find the microcontroller.
+  - Back in Operate, click on ''Read'' to see if PICkit3 can find the microcontroller.
 The Output should result in:
+<code>
 Programmer to target power is enabled - VDD = 3.300000 volts.
 Target device PIC32MX270F256B found.
+</code>
-A simple first test is to light an LED from RA1 which is pin 3 on the microcontroller.
+A simple first test is to light an LED from ''RA1'' which is pin 3 on the microcontroller.
-In the MPLABX IDE, create a new C project and in the main.c file, add the following before the while loop:
+In the MPLABX IDE, create a new C project by doing the following:
-TRISA = 0b00000000; //all PortA pins are output
+<code ini>
-PORTA = 0b00000010; //set pin 3 (RA1) to on. (supply 3.3 volts)
+New Project > Microchip Embedded > Standalone Project
+Next >
-while(1)
+Family: 32-bit MCUs (PIC32)
-{
+Device: PIC32MX270F256B
+Select Tool: PICkit3
+Next >
+Select Compiler: XC32 Compiler
+Project Name: MyTestProject (or anything really)
+(keep all defaults)
+Finish
+Under ''Source Files'':
+	New > C Main File
+Finish
+</code>
+Click the Build Spanner icon to test the project build. Should build successfully.
+Change the whole c file to contain:
+<code c>
+#ifdef __XC32
+    #include <xc.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+int main(int argc, char** argv) {
+    TRISA = 0b00000000; //all PortA pins are output
+    PORTA = 0b00000010; //set pin 3 (RA1) to on. (supply 3.3 volts)
+    return (EXIT_SUCCESS);
 }
+</code>
+The ''#include <xc.h>'' line includes defined variables like ''PORTA'' and ''TRISA''.
-A nice simple test. TRISA means all the A pins (RA0, RA1, RA2 etc). Setting each bit to 0 in this way means that every pin will be set as an output pin. This means that voltage can be output from the pin to power something.
+A nice simple test. ''TRISA'' means all the A pins (RA0, RA1, RA2 etc). Setting each bit to 0 in this way means that every pin will be set as an output pin. This means that voltage can be output from the pin to power something.
-PORTA is the way of turning on or off that voltage. So in the above code, only pin 3 (RA1) will be supplied with 3.3 volts. All the other pins will be 0 volts.
+''PORTA'' is the way of turning on or off that voltage. So in the above code, only pin 3 (RA1) will be supplied with 3.3 volts. All the other pins will be 0 volts.
-As we did earlier on the breadboard, you have a wire from RA1, to a 100Ohm resistor, to an LED and then to ground.
+As we did earlier on the breadboard, you have a wire from ''RA1'', to a 100Ohm resistor, to an LED and then to ground.
 Compile the code. A hex file will be created at:
-project\dist\PIC32MX270F256B-cpp\production\myfile.hex
+  project\dist\<my project name>\production\myfile.hex
-Switch back to the MPLABX IPE and browse for your hex file. Program it to the chip by clicking the Program button.
+Switch back to the MPLABX IPE and browse for your hex file. Program it to the chip by clicking the ''Program'' button.
 The LED should light up. Good stuff. Your development flow is complete.
-[]
-Add flash with internal oscillator
 ===== Programming two blinking LEDs =====
+To blink back and forth between the two leds, change the code to:
+<code c>
+#ifdef __XC32
+    #include <xc.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <plib.h>
+int main(int argc, char** argv) {
+    TRISA = 0b00000000; //all PortA pins are output
+    PORTA = 0b00000001; //set pin 3 (RA1) to on. (supply 3.3 volts)
+    int count = 0;
+    while(1)
+    {
+        if (count >= 500000){
+            mPORTAToggleBits(BIT_0);
+            mPORTAToggleBits(BIT_1);
+            count = 0;
+        }
+        count++;
+    }
+    return (EXIT_SUCCESS);
+}
+</code>
+Notice ''plib.h'' is included. This supports defines like ''mPORTAToggleBits''. All this changes in later versions. This document will be updated at some point.
+And that gives a basic project that will alternate between flashing LEDs.
 ===== What happens if? =====
@@ Line 91: / Line 170: @@
 The following shows what happens, or what could happen if part of the minimum set up is not complete. This is only what I have noticed, the effects could be greater for others.
+^ Component      ^ During Programming       ^ For Execution          ^
-Table of effects
+| Not using a pull up on MCLR to Positive    | No effects     | Could cause random resets on the PIC if the pin is floating. |
-----------------
+| Pull up on MCLR to Negative    | Cannot program     | - |
-Component									For Programming		For Execution
+| No 0.1uf bypass capacitors    | Unstable effects    |No noticeable effect on basic test|
-Not using a pull up on MCLR to Positive		No effects			Safety to keep a floating pin from random resets on the PIC.
+| No External Oscillator  | Not required     | Internal can be used  |
-.1uf bypass capacitors on each side +/-	Unstable effects	No noticeable effect on basic test
+|No AVDD on Pin 28|PIC can't be found|?|
-External Oscillator							Not required		Internal can be used
+|No AVSS on Pin 27|PIC can't be found|Executes normally|
-No AVDD on Pin 28												PIC can't be found
+|No Cap between VCAP on 20 to 21 to GND	|?|Executes normally|
-No AVSS on Pin 27												Executes normally
+|No VDD on Pin 13| ? |Executes normally|
-No Cap between VCAP on 20 to 21 to GND							Executes normally
+|No VSS on Pin 8| ? |Executes normally|
-No VDD on Pin 13												Executes normally
+|No PGEC1 connected | Cannot connect to target device | ? |
-No VSS on Pin 8													Executes normally
+|No PGED1 connected | Cannot connect to target device | ? |
-No PGEC1 connected												Cannot connect to target device
-No PGED1 connected												Cannot connect to target device

User Tools

Site Tools

Differences

Page Tools