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AlphaParticle
Joined: 10 Jun 2012
Posts: 5
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| USB problems... |
 Posted: Sun Jun 10, 2012 4:23 am |
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Hello everyone,
I am trying to leave the old (but lovely) 232 for the new (but ugly) USB. The main reason for this is that it’s almost impossible to see a PC with classical serial ports nowadays. Unfortunately, any attempt I had tried to make the USB stack work has failed. I have copied the code from an example but as I didn’t have all the components I had to adapt it to ones I had. My PIC is a 18F4455 and I’m using a 16 MHz crystal with a couple of 33 pF capacitors. I have used a couple of 95K resistors for the connection sense pin (which is B2), and I have attached a led with a serial resistance to B7 just to check that the core is running at the right speed (the idea is to see a blink for a second) and also, to see it bright continuously when the USB is working. Here’s the code:
| Code: |
#include <18F4455.h>
#device adc=10
#FUSES NOWDT //No Watch Dog Timer
#FUSES WDT128 //Watch Dog Timer uses 1:128 Postscale
#FUSES HS //Crystal osc > 4mhz for PCM/PCH , 3mhz to 10 mhz for PCD
#FUSES NOPROTECT //Code not protected from reading
#FUSES NOBROWNOUT //No brownout reset
#FUSES BORV21 //Brownout reset at 2.1V
#FUSES NOPUT //No Power Up Timer
#FUSES NOCPD //No EE protection
#FUSES STVREN //Stack full/underflow will cause reset
#FUSES NODEBUG //No Debug mode for ICD
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOWRT //Program memory not write protected
#FUSES NOWRTD //Data EEPROM not write protected
#FUSES IESO //Internal External Switch Over mode enabled
#FUSES FCMEN //Fail-safe clock monitor enabled
#FUSES PBADEN //PORTB pins are configured as analog input channels on RESET
#FUSES NOWRTC //configuration not registers write protected
#FUSES NOWRTB //Boot block not write protected
#FUSES NOEBTR //Memory not protected from table reads
#FUSES NOEBTRB //Boot block not protected from table reads
#FUSES NOCPB //No Boot Block code protection
#FUSES LPT1OSC //Timer1 configured for low-power operation
#FUSES MCLR //Master Clear pin enabled
#FUSES NOXINST //Extended set extension and Indexed Addressing mode disabled (Legacy mode)
#FUSES PLL4 //PLL PreScaler divided by 4
#FUSES CPUDIV1 //No System Clock Postscaler
#FUSES USBDIV //USB clock source comes from PLL divide by 2
#FUSES VREGEN //USB voltage regulator enabled
#FUSES ICPRT //ICPRT enabled
#use delay(clock=16000000)
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The code is supposed to transfer through USB the readings from the ADC channel 0..
| Code: |
#include "C:\Trabajos\Proyectos PIC\Prueba_USB\main.h"
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <float.h>
#include <limits.h>
#include <locale.h>
#include <math.h>
#include <setjmp.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdlibm.h>
#include <string.h>
#define USB_CON_SENSE_PIN PIN_B2
#include <usb_cdc.h>
void main()
{
int16 q, q1;
float p;
q1=0;
setup_adc_ports(AN0|VSS_VDD);
setup_adc(ADC_CLOCK_INTERNAL|ADC_TAD_MUL_0);
setup_psp(PSP_DISABLED);
setup_spi(SPI_SS_DISABLED);
setup_wdt(WDT_OFF);
setup_timer_0(RTCC_INTERNAL);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
setup_timer_3(T3_DISABLED|T3_DIV_BY_1);
setup_comparator(NC_NC_NC_NC);
setup_vref(FALSE);
set_adc_channel(0);
set_tris_b(0x0F);
//Blink...
output_low(PIN_B7);
delay_ms(500);
output_high(PIN_B7);
delay_ms(1000);
output_low(PIN_B7);
usb_cdc_init();
usb_init();
do{
usb_task();
if(usb_enumerated()){
output_high(PIN_B7);
q = read_adc();
if(q!=q1){
p = 5.0 * q/1024.0;
printf(usb_cdc_putc, "\n\r Voltaje = %01.2fV",p);
}
q1 = q;
delay_ms(500);
}
}while(TRUE);
}
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When I turn on the PIC, I can see that the B7 led blinks for a second.. so then I connect it to the PC (Windows 7) and the OS shows me that it is an “unknown device” (code 43)..
Please If you have any ideas, would be very welcome |
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Douglas Kennedy
Joined: 07 Sep 2003
Posts: 755
Location: Florida
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| Posted: Sun Jun 10, 2012 5:35 am |
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I case you didn't know you need a cap on the vusb pin it isn't that critical for the value 0.22uf is recommended but even 1uf will work.
Next check the wiring, win7 I believe will report a 43 error if the D- and D+ are reversed.
My fuses are
| Code: |
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NODEBUG,USBDIV,PLL4,CPUDIV2,VREGEN
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Below is some documentation for a 2455 usb to can bus project
| Code: | /////// 18F2455
/// +-----------+
//// mclr_|1 28|_B7 PCD
// | |
// A0_|2 27|_B6 PGC
// | |
/// Green Led A1_|3 26|_B5
// | |
// A2_|4 25|_B4---- 100k-->5v
// | |
//// Red LED A3_|5 24|_B3 Debugger
// | |
// A4_|6 23|_B2 INT of MCP2515 Pin 12
// | |
/// MCP2515 Reset <---- A5_|7 22|_B1 SCK -->SPIclk to MCP2515 Pin13
// | |
// Vss Gnd_|8 21|_B0 SDI--->SO MCP2515 Pin15
// | |
//// +---|15pf|--+-____--- Osc1_|9 20|_5v Vdd
// Gnd-| 16Mhz Xtal | |
// +---|15pf|--+-------- Osc2_|10 19|_Gnd Vss
// | |
/// C0_|11 18|_C7 SDO--->SI MCP2515 Pin14
// | |
// C1_|12 17|_C6
// | |
/// CS to MCP2515 <----C2_|13 16|_C5 D+ USB green
// | |
// Gnd--------|0.47uf|----Vusb_|14 15|_C4 D- USB white
// data sheet is 0.22uf | |
// use polyester +-----------+
// Note we are using 1uf polyester
/////////////////////////////////////////////
///
/// 5v ----/\/\/\--+--__\__---- GND
/// 100k | NO switch
/// |
/// B4 -------------
///
/// Vusb ------| |----- GND
////
////
/////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
///
/// usb connector
/// ___________ _______
/// | 4 3 2 1 | / \
/// |=========| | 1 2 |
/// |_________| | 4 3 |
// |_______|
///
/// 1 Red wire VCC 5v
/// 2 White D-
/// 3 Green D+
/// 4 Black Gnd
////////////////////////////////////////////////////////////////////////// |
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AlphaParticle
Joined: 10 Jun 2012
Posts: 5
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| Posted: Sun Jun 10, 2012 7:09 am |
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Hey Douglas! Thank you SOOOOOOOOOOOOOOOOO MUCH!!  It was the capacitor!! I simply can’t believe I have spent all these days just for a capacitor!  It has worked perfectly as it was supposed to work! Thanks!! |
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