The dsPic33 and FLEX board

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The dsPic33 and FLEX board

Paolo Pagano

Corso di Sistemi in Tempo Reale Laurea in Ingegneria

dell‘Automazione a.a. 2008-2009

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Course Outline (1/2)

• Second day (24

^th

)

• FSM implementation in C (slides by prof. Di Natale)

• A case study

• Real Hardware demonstration

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Outline

• Introduction to the FLEX board

• A FSM instantiation on the FLEX

• Visit the web site:

http://feanor.sssup.it/~pagano/personalWEB/courses.htm

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FLEX

idea:

cheap, small, easy-to-use evaluation boards

Typical applications:

• industrial sensing and control

• small robots

• wireless sensor networks

• demo boards for university labs

embedded boards

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Flex

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board layout

Main processing board add-on boards

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add-on boards

1 - 2.54mm pattern 2 - 2.54mm alternate

pattern

(RJ45 / RS232 connectors) 3 - 1.27mm pattern

(SMD components) 4 - 5.08mm pattern

(clamps)

breadboard

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add-on boards

1 - Serial port 2

(RS232 / RS422 / RS485 / TP-UART)

2 - Serial port 1

(RS232 / RS422 / RS485)

3 - CAN port 1 4 - CAN port 2 5 - I2C port 6 - SPI port

7 - 10Mbit Ethernet 8 - RJ45 Ethernet

multibus

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Our test device

• It is an extended basic flex board;

• We connected the dsPic33 core to:

• Set of buttons (input);

• Set of leds (output);

• LCD display (status display).

• We have in mind to simulate an elevator controller:

• its implementation starts from FSM modeling;

• the model is validated by OTS tools (Uppaal);

• the code generation is done by hand.

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How to program our device

• Our FLEX board should run a specific program (firmware);

• We need a compiler to translate from C to

machine code;

• We need a linker command file that allows the test

code to be targeted to the dsPIC33;

• We need a tool to transfer the firmware from the PC to the MCU flash memory.

MPLAB_C30

gld script

Microchip ICD2

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COFF file structure

http://delorie.com/djgpp/doc/coff/

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Peripheral Mapping

• Expansion Board PIN I/O:

• Leds -> PortD (output)

• But’s -> PortG (input)

• LCD -> PortA (output)

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MCU I/O

• A port is a set of analog/digital enabled pins.

• A port can be configured to catch analog or digital inputs. Digital signals can have a duration (like those generated by pushing buttons) or can be “levels” (latch mode).

• of course finite signals must be caught while high.

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How to configure ports

• dsPic has 7 ports defined in the included header:

• #include "p33FJ256MC710.h"

• Configuring a port for OUTPUT

void initLeds (void) {

TRISDbits.TRISD0 = 0;

}:

• Configuring a port for INPUT:

void initButtons (void) {

TRISGbits.TRISG6 = 1;

} 16 pels

of the LCD

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How to read/write ports

• Writing OUTPUT:

void setLed ( int led, int on_off ){

switch (led){

case 0:

LATDbits.LATD0 = on_off;

break;

case 1:

break;

case 2:

break;

• Reading INPUT:

int getButton ( int j ){

switch (j){

case 0:

return !PORTGbits.RG6;

case 1:

case 2:

case 3:

} }

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the end

Questions ?

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HOWTO initialize and transit

static enum State {

IDLE, S0, S1, S2, S3 };

static enum Signal {

ABSENT, GO_TO_S0, GO_TO_S1, GO_TO_S2, GO_TO_S3

};

void FSMInit(FSM *me){

me->state_ = IDLE;

}

void FSMTran_(FSM *me, unsigned int dest)

{

me->state_ = dest;

}

enum Signal FSMGetSignals(FSM *me){

if (b0)

return GO_TO_S0;

else if (b1)

return GO_TO_S1;

else if (b2)

return GO_TO_S2;

else if (b3)

return GO_TO_S3;

return ABSENT;

}