tutorials an usb english

tinyurl.com/SanUSB 05/06/2011

SanUSB

The transfer application firmware for microcontrollers is usually accomplished through

a specific hardware programmer. Through the SanUSB tool, executable in Linux, Mac

OSX and Windows® operating systems, it is possible the discharge of application firmware

for microcontrollers directly via USB, as well as generating a virtual serial communication

port using the USB interface. The SanUSB tool allows to program application .hex into the

chip using the standard USB connectivity of PIC microcontrollers.

This tool is composed of software and a circuit based on the microcontroller with USB

interface for the development of embedded systems [1], i.e., systems that manipulate data

inside another larger system [2].

To facilitate the tool application, the software is free and available from the archives at

http://www.tinyurl.com/SanUSB [3]. Using this tool, students of IFCE were consecutively

three time champions of the IFCE Robotics Competition (2007, 2008 and 2009),

champions of the Brazilian Fair of Science and Engineering (FEBRACE09) in the

University of São Paulo in Engineering Category (2009), obtained the Innovation Award

for Technology Application at the 2009 Feria Explora Medellin in Colombia and became

Champions in the International Forum of Science and Engineering 2010 in Chile in the

Supranivel Category [4-8].

Using the SanUSB tool, it also is possible to suppress the following items in the

development of embedded systems:

(a) A specific device for microcontroller memory programming;

(b) TTL/RS-232 interface for bi-directional serial communication protocol emulated by

USB communication device class (CDC);

(c) Power supply, since the power source is derived from the PC USB channel;

(d) Externally analog-digital converter (ADC), because the microcontroller has

internally 10 ADC of 10 bits. Using externally ADC increases the cost of data acquisition

cards;

(e) Simulation software, whereas the simulation program and hardware can be made

quickly and effectively in their own development circuit.

Besides all these advantages, modern laptops and computers of today no longer have

parallel and serial EIA/RS-232 communication interfaces, only USB.


The SanUSB tool enables user-friendly programming and also real debugging directly

through the virtual serial emulation. This can be created quickly and effectively at the very

moment the microcontroller is connected directly to a PC, through the USB interface.

Figure 1 shows an illustration of the SanUSB tool programming process.

Figure 1. Illustration of the SanUSB tool programming process.

To enable all these features, compatible with Linux, Mac OSX and Windows®

operating systems, is necessary to burn previously only once an USB manager

gerenciador.hex file with a specific microcontroller hardware or with the simple

programming circuit described at the end of this tutorial.

The application firmware is sent directly from the PC to the USB microcontroller with

the programming interface. Initially, the microcontroller pin 1 must be connected to Gnd

via a push button while the USB cable is connected between PC and microcontroller, then

the compiled application firmware .hex file can be selected in Open button of the

programming interface shown in Figure 2 and the microcontroller is programmed by

pressing the Burn & Reset button.


Figure 2. SanUSB tool programming Interface.

It is possible to download this software tool at the following link:

http://www.4shared.com/file/sIZwBP4r/100727SanUSB.html

For application programs in C can be written to the microcontroller via USB, it is

necessary to compile and to turn them into machine language .hex. There are several

compilers that can be used by this tool, including the SDCC, the C18, Hi-Tech and CCS. At

the end of this tutorial there is firmware models to use the SanUSB tool with mentioned C

compilers.

The basic mounted SanUSB circuit on a breadboard with 28 and 40 pins

microcontroller are shown in Figures 3 and 4:


Figure 3. Basic SanUSB circuit with 28 pins microcontroller.



The basic circuit components are:

• a PIC microcontroller USB family (18F2550, 18F2455, 18F4550, etc.).

• a crystal of 20MHz;

• two 22pF capacitors;

• two 1uF capacitors;

• a 2k2 pull-up resistor and a button for programming at pin 1;

• a diode;

• and USB cable.

Note that this multi-platform can also be implemented in any development PIC

microcontroller board because it uses the reset button at pin 1 as the programming

button via USB. When you connect the USB cable with pin 1 on the Gnd (0V, the

microcontroller enters in programming state via USB (LED at pin B7 on) and after the

reset, with pin 1 on the Vcc (through the fixed 2K2 pull-up resistor), the microcontroller

comes into operation state of the application firmware that was compiled.

The figure 5 shows a photo of the SanUSB tool mounted on breadboard following

the previous circuit and also the position of each terminal on the USB connector to be

connected to the PC.


The figure 6 shows the PCB, available in the Archives of SanUSB Group, and the

circuit for this tool with input for external power supply.

.


Figure 6. Basic SanUSB PCB.

If you prefer to make the card, you can also print on glossy paper black PCB shown

in Figure 7 is already in full size, corrode, stick (brown spots) and solder the components.

More information available at: http://www.youtube.com/watch?v=8NhNsNw5BfU.

Figure 7. Basic SanUSB PCB circuit design.


During the C program development just insert at the beginning of the program in C,

the library SanUSB header (# include <SanUSB.h>) contained within the Examples and

Library CCS folder you should have added, along with the other libraries in this folder

within the Drivers located in the installed folder of the compiler (C: \ program Files \ PICC

\ Drivers). This library contains the instructions for the USB PIC operating system settings.

The program example 1 below contained in the folder Examples, switch a led

connected to pin B7 every 0.5 seconds.

#include <SanUSB.h>

void main()

clock_int_4MHz();//Function necessary to enable the dual clock (48MHz for USB and 4MHz for CPU)

while (1)

output_toggle(pin_B7); // comuta Led na função principal

delay_ms(500);

The program below blinks three 3 leds connected to pins B5, B6 and B7.

#include <SanUSB.h>

main()

clock_int_4MHz();//Função necessária para habilitar o dual clock (48MHz para USB e 4MHz para CPU)

while (1)

output_high(pin_B5); // Pisca Led na função principal

delay_ms(500);

output_low(pin_B5);

output_high(pin_B6);

delay_ms(500);

output_low(pin_B6);


delay_ms(500);

output_low(pin_B7);

The Compiled files. hex as well as the firmware source are available in the folder

Examples available at: http://www.4shared.com/file/sIZwBP4r/100727SanUSB.html

.


Serial Emulation

In this topic is shown a method of bi-directional serial communication channel

through the USB PIC18Fxx5x. One of the simplest ways is through the protocol

Communications Device Class (CDC), which is standard on Linux and Mac OSX and

emulates a virtual COM port RS-232 through the USB channel. Thus, it is possible to

communicate with ASCII characters via USB by software serial monitor RS-232 as the

Cutecom, minicom or other software with serial interface. The application firmware must

heve the CDC library (# include <usb_san_cdc.h>), responsible for this virtual RS-232 port

emulation via USB. The serial emulation is widely used also to debug by printing variables

via USB during actual program execution. Thus, the programmer can find possible errors in

the firmware programming.

For the compilation of a serial emulation application program, such as

exemplo_emulSerial.c. The CDC library (# include <usb_san_cdc.h>) should be in the

same folder as the firmware or installed into the folder of the compiler (C : \ program Files \

PICC \ Drivers). The firmware exemplo_emulSerial.c below commands the state of a led

on pin B7 with the L and D keys on the PC keyboard. The CDC functions most commonly

used for communication with virtual COM are:

• usb_cdc_putc () - microcontroller sends ASCII characters emulated via USB.

Example: printf (usb_cdc_putc, "\ r \ nEndereco to write:");

• usb_cdc_getc () - retains an emulated ASCII character via USB.

Ex: data = usb_cdc_getc () / / retains a character in data variable

• gethex_usb () - holds a hexadecimal number entered from the keyboard.

Example: value = gethex_usb ();// holds a hexadecimal in the value variable

• usb_cdc_kbhit () - Warn to TRUE (1) to get a new character in the USB PIC

receive buffer.


Example: if (usb_cdc_kbhit ()) data = usb_cdc_getc ();

#include <SanUSB.h>

#include <usb_san_cdc.h>

BYTE comando;

main()

clock_int_4MHz();

usb_cdc_init(); // Inicializa o protocolo CDC

usb_init(); // Inicializa o protocolo USB

usb_task();

while (TRUE)

if (usb_cdc_kbhit( ))

comando=usb_cdc_getc();

if (comando=='L') output_high(pin_b7); printf(usb_cdc_putc, "\r\nLed Ligado!\r\n");

if (comando=='D') output_low(pin_b7); printf(usb_cdc_putc, "\r\nLed Desigado!\r\n");


delay_ms(300);

output_low(pin_B6);

delay_ms(300);

More information can be also obtained from the video:

http://www.youtube.com/watch?v=cRW99T_qa7o .

Enjoy!

[email protected]

SIMPLE CIRCUIT TO gerenciador.hex PROGRAMMING

For serial microcontroller programming of the gerenciador.hex is necessary only

three resistors of 10 kΩ, a DB9 serial cable (RS-232) and an 5V external voltage supply,

which can be obtained from the USB port. The circuit and the photo below show the simple

connecting pins scheme.


This circuit seen from the PC DB9 COM port can be viewed in the figure below.

This circuit works with the programming software PICPGM (detected as JDM

Programmer) or WinPIC (detected as COM84 Programmer). The Winpic appears more

stable, because after the microcontroller detection, the microcontroller can be programmed,

even pointing “ERROR: Programming failed”, the file gerenciador.hex proved to be

programmed correctly in the microcontroller to manage programming via the USB port on

Windows ®, Linux and Mac OSX operating systems.

The software Winpic can be downloaded from www.qsl.net/dl4yhf/winpicpr.html or

http://www.4shared.com/get/1uP85Xru/winpicprCOM84.html.


After installation, run the program. In "Device, Config" select the microcontroller.

Once the microcontroller is connected to RS-232 PC COM port, go to "Interface", select

"COM84 programmer for serial port", and press "Initialize." If the software indicated that

the boot was "Success", then the program is prepared to program the gerenciador.hex in

microcontroller. For the programming, select File and then “Load & Program Device” and

then select the file gerenciador.hex. As previously mentioned, even after the programming

and verification appear "Programmed Failed", it is likely that the gerenciador.hex has been

programmed correctly.


Firmware Header file for CCS C Compiler

SanUSB.h header File:

#include <18F4550.h> //This library 18F4550.h is valid for the whole family USB PIC18Fx5xx

#device ADC=10

#fuses HSPLL,PLL5, USBDIV,CPUDIV1,VREGEN,NOWDT,NOPROTECT,NOLVP,NODEBUG

#byte OSCCON=0XFD3

#use delay(clock=48000000)// USB standard frequency (cpu and timers 12 MIPS = 4/48MHz)

//#use delay(clock=4000000) // internal Oscillator Clock of 4MHz

#use rs232(baud=9600, xmit=pin_c6, rcv=pin_c7)

//SanUSB program memory allocation

#define CODE_START 0x1000

#build(reset=CODE_START, interrupt=CODE_START+0x08)

#org 0, CODE_START-1

void clock_int_4MHz(void)

//OSCCON=0B01100110; //with dual clock -> cpu and timers #use delay(clock=4000000)

while(read_eeprom(0xfd));


Firmware Modification for Microchip C18 compiler

/* www.tinyurl.com/SanUSB */

#include "p18F4550.h"

void low_isr(void);

void high_isr(void);

#pragma code low_vector=0x1018

void interrupt_at_low_vector(void)

_asm GOTO low_isr _endasm

#pragma code

#pragma code high_vector=0x1008

void interrupt_at_high_vector(void)

_asm GOTO high_isr _endasm

#pragma code

#pragma interruptlow low_isr


void low_isr (void)

return;

#pragma interrupt high_isr

void high_isr (void)

return;

void main( void )

...;

Firmware Modification for SDCC

Example Format


#include <pic18f4550.h>

#pragma code _reset 0x001000

void _reset( void ) __naked


__asm

EXTERN __startup

goto __startup

__endasm;

#pragma code _high_ISR 0x001008

void _high_ISR( void ) __naked

__asm

retfie

__endasm;

#pragma code _low_ISR 0x001018

void _low_ISR( void ) __naked

__asm

retfie

__endasm;

void main()


Firmware Modification for MikroC

Example Format for Bootloader


#pragma orgall 0x1000

void interrupt(void) org 0x1008

;

void interrupt_low(void) org 0x1018

;

void main()

......;

Hi-Tech C Compiler

step1:goto Build option

step2:linker tap

step3:set offset : 1000


Firmware Modification for Microchip ASM compiler


processor PIC18F4550

#include"p18f4550.inc"

org 0x1000

goto init

org 0x1020

goto int_isr

init

... ; initialization

loop

... ; code

goto loop

int_isr

... ; interrupt code

retfie

end

REFERENCES

Grupo SanUSB (2011). Arquivos do Grupo SanUSB. Retirado em 05/01/11, no World

Wide Web: www.tinyurl.com/SanUSB/.


Jornal O Povo (2011). Da escola pública para o mundo. Retirado em 05/01/11, no World

Wide Web:

http://www.opovo.com.br/app/opovo/cienciaesaude/2011/01/08/noticiacienciaesaudejor

nal,2086691/da-escola-publica-para-o-mundo.shtml.

Jucá, S. et al.(2011). A low cost concept for data acquisition systems applied to

decentralized renewable energy plants. Retirado em 05/01/11, no World Wide Web:

http://www.mdpi.com/1424-8220/11/1/743 .

Jucá, S. et al.(2011). Gravação de microcontroladores PIC via USB pelo terminal do

Linux. Retirado em 05/03/11, no World Wide Web:

http://www.vivaolinux.com.br/artigo/Gravacao-de-microcontroladores-PIC-via-USB-

pelo-terminal-do-Linux/.

Jornal O Povo (2010). De Maracanaú para Eslováquia. Retirado em 05/01/11, no World

Wide Web: http://publica.hom.opovo.com.br/page,489,109.html?i=2051467 .

Diário do Nordeste (2010). Robô cearense. Retirado em 05/01/11, no World Wide Web:

http://diariodonordeste.globo.com/materia.asp?codigo=861891.

TV Diário (2010). Feira do Empreendedorismo SEBRAE. Retirado em 05/01/11, no World

Wide Web: http://www.youtube.com/watch?v=8Y7gOPd_zN4.

TV Verdes Mares (2009). Estudantes competem com robôs. Retirado em 05/01/11, no

World Wide Web: http://tvverdesmares.com.br/bomdiaceara/estudantes-competem-com-

robos/.

TV Cidade (2009). Projetos Comsolid/Setapi IFCE. Retirado em 05/01/11, no World Wide

Web: http://www.youtube.com/watch?v=i_waT0_201o.

Jucá, S. et al.(2009). SanUSB: software educacional para o ensino da tecnologia de

microcontroladores. Retirado em 05/01/11, no World Wide Web:

http://www.cienciasecognicao.org/pdf/v14_3/m254.pdf .

Diário do Nordeste (2007). Alunos estimulados a construir robôs. Retirado em 05/01/11, no

World Wide Web: http://diariodonordeste.globo.com/materia.asp?codigo=491710.

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