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PICoHolic
Joined: 04 Jan 2005
Posts: 224
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| I2C Master Slave (18F4550) once again!? [FINALLY RESOLVED] |
 Posted: Fri Apr 27, 2007 12:30 am |
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My goal is to connect 18F4550 I2C master to 18F4550 I2C slave.
I2C master is by software (it works fine with other slaves)
I2C slave is by hardware (Code taken from the example provided by CCS)
Below are the two codes.
The problem is that the master is always reading 0xFF
Master Code
| Code: |
#include <18F4550.h>
#device adc=8
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NOBROWNOUT,NODEBUG,USBDIV,PLL5,CPUDIV1,VREGEN, NOPBADEN, ICPRT
#use delay(clock=48000000)
#use i2c(Master,Slow=100000,sda=PIN_C0,scl=PIN_C1)
#use rs232(baud=115200,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
#byte PORTA = 0xF80
#byte PORTB = 0xF81
#byte PORTC = 0xF82
#byte PORTD = 0xF83
#byte PORTE = 0xF84
#byte TRISE = 0xF96
#include "MDIO.h"
///////////////////////////////////////////////////////////////////////////////
// USB
#include <usb_cdc.h>
///////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////
#use delay(clock=48000000)
///////////////////////////////////////////////////////////////////////////////
void main()
{
unsigned int8 Buff[16];
unsigned int8 BuffPointer=0;
int16 Val;
int8 i2cVal;
MDIOPacket MDIO_P;
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
setup_spi(FALSE);
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);
setup_low_volt_detect(FALSE);
setup_oscillator(False);
delay_ms(1000);
//////////////////////////////////////////////////////////////
Init_MDIO(&MDIO_P);
//////////////////////////////////////////////////////////////
usb_cdc_init();
usb_init();
while(!usb_cdc_connected()) {}
while (TRUE)
{
usb_task();
if (usb_enumerated())
{
Buff[BuffPointer] = usb_cdc_getc();
if (++BuffPointer == 5)
{
BuffPointer = 0;
switch (Buff[0])
{
case 0xF0: // Register Data
MDIO_P.OP = OP_REG;
MDIO_P.PRTAD = Buff[1];
MDIO_P.DEVAD = Buff[2];
MDIO_P.DATA_ADDR = Buff[4];
MDIO_P.DATA_ADDR <<= 8;
MDIO_P.DATA_ADDR |= Buff[3];
write_MDIO(MDIO_P);
break;
case 0xF1: // Write Data
MDIO_P.OP = OP_WR;
MDIO_P.PRTAD = Buff[1];
MDIO_P.DEVAD = Buff[2];
MDIO_P.DATA_ADDR = Buff[4];
MDIO_P.DATA_ADDR <<= 8;
MDIO_P.DATA_ADDR |= Buff[3];
write_MDIO(MDIO_P);
break;
case 0xF2: // Read Data
MDIO_P.OP = OP_RD;
MDIO_P.PRTAD = Buff[1];
MDIO_P.DEVAD = Buff[2];
Val = read_MDIO(MDIO_P);
usb_cdc_putc( Val & 0x00FF );
usb_cdc_putc( Val >> 8 );
break;
case 0xF3: // Post Read data + increment
MDIO_P.OP = OP_RDI;
MDIO_P.PRTAD = Buff[1];
MDIO_P.DEVAD = Buff[2];
Val = read_MDIO(MDIO_P);
usb_cdc_putc( Val & 0x00FF );
usb_cdc_putc( Val >> 8 );
break;
case 0xF4: //// I2C TEST ///////////
i2c_start();
i2c_write(0xE0);
i2c_write(0x00);
i2c_start();
i2c_write(0xE1);
i2cVal = i2c_read(0);
i2c_stop();
usb_cdc_putc(i2cVal);
break;
}
}
}
}
}
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Slave Code
| Code: |
#include <18F4550.h>
#device adc=8
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NOBROWNOUT,NODEBUG,USBDIV,PLL5,CPUDIV1,VREGEN, NOPBADEN, ICPRT
#use delay(clock=48000000)
#use i2c(SLAVE, SDA=PIN_B0, SCL=PIN_B1, address=0xE0)
///////////////////////////////////////////////////////////////////////////////
// USB
#include <usb_cdc.h>
///////////////////////////////////////////////////////////////////////////////
#byte SSPCON1 = 0xFC6
#bit SSPOV = SSPCON1.6
///////////////////////////////////////////////////////////////////////////////
BYTE address, buffer[0x10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8' };
//////////////////////////////////////////////////////////////////////////////
#INT_SSP
void ssp_interupt ()
{
BYTE incoming, state;
state = i2c_isr_state();
if(state < 0x80) //Master is sending data
{
incoming = i2c_read();
if(state == 1) //First received byte is address
address = incoming;
if(state == 2) //Second received byte is data
buffer[address] = incoming;
}
if(state == 0x80) //Master is requesting data
{
i2c_write(buffer[address]);
}
SSPOV = 0;
}
///////////////////////////////////////////////////////////////////////////////
#use delay(clock=48000000)
///////////////////////////////////////////////////////////////////////////////
void main()
{
unsigned int8 Buff[16];
unsigned int8 BuffPointer=0;
int16 Val;
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
setup_spi(FALSE);
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);
//setup_low_volt_detect(FALSE);
//setup_oscillator(False);
enable_interrupts(INT_SSP);
clear_interrupt(INT_SSP);
enable_interrupts(GLOBAL);
//////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////
while (TRUE)
{
}
}
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Compiler version 4.029 Silicon revision A3 
Mater is reading 0xFF instead of 0x30 ('0'). Somtimes it stalls unless i remove one of the I2C lines (obvious).
Any suggestions? I need to make it work.. It's critical
Note: I've already read all the previous posts related to I2C slave!!
Last edited by PICoHolic on Thu May 03, 2007 2:51 am; edited 5 times in total |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Apr 27, 2007 1:32 am |
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You shouldn't address this post to me. You shouldn't assume that
I know the answer. Please edit the title so it's not addressed to me.
Then you might get help from other people. |
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PICoHolic
Joined: 04 Jan 2005
Posts: 224
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| Posted: Fri Apr 27, 2007 1:48 am |
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Sorry PCM Programmer. Maybe i shouldnt do it. I removed it.
Sorry once again but i really need to make it happen.
Thank you. |
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PICoHolic
Joined: 04 Jan 2005
Posts: 224
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| Posted: Fri Apr 27, 2007 7:19 am |
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Any one?
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Apr 27, 2007 11:36 am |
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You have a combined "USB/i2c Master-Slave" project. I have never
done a PIC USB project. I can only help with the i2c Master-Slave
part, and then, only if it's kept simple.
If you want me to help, you need to post new test programs, with all
the USB code removed. Make it only be i2c Master-Slave code.
Cut out anything (including switch-case statements) that has anything
to do with the USB. Then test it, prove that it fails, and post it. |
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PICoHolic
Joined: 04 Jan 2005
Posts: 224
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| Posted: Sat Apr 28, 2007 1:52 pm |
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Thank you PCM programmer.
I will get back with you on monday. (Because of the weekend)
I will post much simple codes. In fact i dont care about having and I2C mater with USB (it's already working) all i need is an I2C slave with USB. as you've mentioned i'll remove the USB code but i need to keep the USB configuration bits.
Thank you once again |
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PICoHolic
Joined: 04 Jan 2005
Posts: 224
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| Posted: Mon Apr 30, 2007 6:09 am |
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here it is
Slave
| Code: |
#include <18F4550.h>
#device adc=8
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NOBROWNOUT,NODEBUG,USBDIV,PLL5,CPUDIV1,VREGEN, NOPBADEN, ICPRT
#use delay(clock=48000000)
#use i2c(SLAVE, SDA=PIN_B0, SCL=PIN_B1, address=0xE0, FORCE_HW)
#use rs232(baud=115200,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8, errors)
#byte PORTA = 0xF80
#byte PORTB = 0xF81
#byte PORTC = 0xF82
#byte PORTD = 0xF83
#byte PORTE = 0xF84
#byte TRISE = 0xF96
#byte LATB = 0xF8A
#byte TRISB =0xF83
#byte SSPADD = 0xFC8
#byte SSPCON1 = 0xFC6
#byte SSPCON1 = 0xFC6
#bit SSPOV = SSPCON1.6
///////////////////////////////////////////////////////////////////////////////
BYTE address, buffer[0x10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8' };
//////////////////////////////////////////////////////////////////////////////
int8 States[32][2];
int8 statespointer = 0;
//////////////////////////////////////////////////////////////////////////////
#INT_SSP
void ssp_interupt()
{
BYTE incoming, state;
state = i2c_isr_state();
states[statespointer++][0] = state;
states[statespointer-1][1] = 0xAA;
//putc(state);
if(state < 0x80) //Master is sending data
{
incoming = i2c_read();
//putc(incoming);
states[statespointer++][0] = state;
states[statespointer-1][1] = incoming;
if(state == 1) //First received byte is address
{
address = incoming;
//putc('a');
}
if(state == 2) //Second received byte is data
{
buffer[address] = incoming;
//putc('d');
}
}
if(state == 0x80) //Master is requesting data
{
i2c_write(buffer[address]);
//putc('W');
}
SSPOV = 0;
}
///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////
void main()
{
unsigned int8 Buff[16];
unsigned int8 BuffPointer=0;
int16 Val;
int i;
////////// PROCESS ERRATA //////////////
TRISB = 0x00;
LATB = 0x00;
TRISB = 0xFF;
#ASM
MOVF 0xFC9,W
MOVFF 0x40,0xFC9
BSF 0xFC6.4
BCF 0xF9E.3
Lp: BTFSC 0xFC7.0
BRA Lp
MOVLW 0xE0
MOVWF SSPADD
MOVLW 0x36
MOVWF SSPCON1
#ENDASM
/////////////////////////////
setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
//setup_spi(FALSE);
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);
//setup_low_volt_detect(FALSE);
//setup_oscillator(False);
//printf("Hello World\n\r");
enable_interrupts(INT_SSP);
clear_interrupt(INT_SSP);
enable_interrupts(GLOBAL);
//////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////
while (1)
{
if (statespointer == 2)
{
disable_interrupts(INT_SSP);
for (i=0;i<statespointer;i++)
printf("\n\rState:%X Incom:%X",states[i][0], states[i][1]);
statespointer = 0;
clear_interrupt(INT_SSP);
enable_interrupts(INT_SSP);
}
}
}
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Master
| Code: |
#include <18F4550.h>
#device adc=8
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NOBROWNOUT,NODEBUG,USBDIV,PLL5,CPUDIV1,VREGEN, NOPBADEN, ICPRT
#use delay(clock=48000000)
#use i2c(Master, SDA=PIN_C0, SCL=PIN_C1, slow=100000)
#byte PORTA = 0xF80
#byte PORTB = 0xF81
#byte PORTC = 0xF82
#byte PORTD = 0xF83
#byte PORTE = 0xF84
#byte TRISE = 0xF96
void main()
{
int8 i2cVal;
set_tris_b(0x00);
PORTB = 0xFF;
setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
setup_spi(FALSE);
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);
//setup_low_volt_detect(FALSE);
//setup_oscillator(False);
//////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////
delay_ms(1000);
output_low(PIN_B7);
i2c_start();
delay_ms(10);
i2c_write(0xE0);
delay_ms(10);
i2c_write(0x00);
delay_ms(10);
i2c_write('A');
delay_ms(10);
i2c_stop();
delay_ms(10);
/*
i2c_start();
delay_ms(10);
i2c_write(0xE1);
i2cVal = i2c_read(0);
delay_ms(10);
i2c_stop();
delay_ms(10);
if (i2cVal == 0x30)
output_high(PIN_B7);
else
output_low(PIN_B5);
*/
output_high(PIN_B7);
while (1)
{
}
}
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The slave is responding to master writes. but the state value seems to be wrong. the output taken from hyperterminal shows:
State:00 Incom:AA
State:00 Incom:00
State:01 Incom:AA
State:01 Incom:41
State 2 never shows up!
right?
Also the slave is not responding to mater reads. The master stalls.
Thank you |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Apr 30, 2007 12:11 pm |
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Your master code to read a byte from the slave doesn't look correct.
See this post. This shows how to write a byte to the Ex_Slave.c code,
and how to read it back. You should do your 'read' code in the same
way:
http://www.ccsinfo.com/forum/viewtopic.php?t=28097&start=9
Then the read code should start working. (Change the i2c addresses
to the ones that you're using).
---------
Also, you have some code where you do a post-increment on an
array index and then in the next access, you subtract one from it.
Example:
| Quote: |
states[statespointer++][0] = 0x55;
states[statespointer-1][1] = 0xAA;
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Suppose the index (statespointer) is initially 0. The 0x55 will be
written to states[0][0]. Then the index is incremented and becomes 1.
Then in your next access, you decrement it back to 0. The 0xAA is
written to states[0][1].
So your code is the same as the following:
| Code: | states[statespointer][0] = 0x55;
states[statespointer][1] = 0xAA; |
You don't need the "post-increment and then subtract 1" stuff.
It doesn't do anything. |
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PICoHolic
Joined: 04 Jan 2005
Posts: 224
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| Posted: Tue May 01, 2007 1:29 pm |
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Thank you PCM Programmer
| Quote: | | Your master code to read a byte from the slave doesn't look correct. |
it is correct. the read code is commented. i was just writing. If you take a look on the i2c code (master + USB) posted previously, it exactly matches your suggested code. And it was not working.
| Code: |
case 0xF4: //// I2C TEST ///////////
i2c_start();
i2c_write(0xE0);
i2c_write(0x00);
i2c_start();
i2c_write(0xE1);
i2cVal = i2c_read(0);
i2c_stop();
usb_cdc_putc(i2cVal);
break;
|
Also
| Quote: | Also, you have some code where you do a post-increment on an
array index and then in the next access, you subtract one from it.
Suppose the index (statespointer) is initially 0. The 0x55 will be
written to states[0][0]. Then the index is incremented and becomes 1.
Then in your next access, you decrement it back to 0. The 0xAA is
written to states[0][1]. |
This code is intented for troubleshooting and it's working as intended: states[i][0] has the state and states[i][1] has the incoming byte or 0xAA (used as a flag)
As a synthesis:
State:00 --> incoming: 00 (internal address)
State 01 --> incoming: 41 ('A' data)
I've been dealing with i2c master long time ago but it's my first time in i2c slave.
In i2c slave when state = 1 it means it's first byte, if state = 2 it means the 2nd. BUT when troubleshooting i found that state=0 is frst byte and so on...
Anyway the slave is responding to master writes but not to master reads.
Thank you. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue May 01, 2007 1:38 pm |
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All I know is, make a test where the slave PIC is running the Ex_Slave.c
code. Then put the code from the following post into the Master PIC.
http://www.ccsinfo.com/forum/viewtopic.php?t=28097&start=9
Modify the #include, and #use statements so it's correct for your PICs.
That will prove if your Master-to-Slave hardware connections are correct
(including pull-up resistors on SDA and SCL, and a ground connection
between the two boards), and it will prove if your compiler version is
able to generate correct code for i2c Master and Slave.
You need to get down to basics and prove that everything works at a
low level, before you start adding your application code.
That's the reason for my suggestion of doing this test. |
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PICoHolic
Joined: 04 Jan 2005
Posts: 224
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| Posted: Wed May 02, 2007 3:41 am |
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OK here it is:
Master:
| Code: |
#include <18F4550.h>
#device adc=8
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NOBROWNOUT,NODEBUG,USBDIV,PLL5,CPUDIV1,VREGEN, NOPBADEN, ICPRT
#use delay(clock=48000000)
#use i2c(Master, SDA=PIN_C0, SCL=PIN_C1, slow=100000)
#byte PORTA = 0xF80
#byte PORTB = 0xF81
#byte PORTC = 0xF82
#byte PORTD = 0xF83
#byte PORTE = 0xF84
#byte TRISE = 0xF96
/////////////////////////////////////////////
void main()
{
int8 i2cVal;
set_tris_b(0x00);
PORTB = 0xFF;
setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
setup_spi(FALSE);
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);
//setup_low_volt_detect(FALSE);
//setup_oscillator(False);
//////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////
delay_ms(1000);
output_low(PIN_B7);
output_low(PIN_B5);
// Write the letter 'B' to the slave board.
i2c_start();
i2c_write(0xE0);
i2c_write(0x00);
i2c_write('B');
i2c_stop();
// Read from the slave board and display the data.
i2c_start();
i2c_write(0xE0);
i2c_write(0x00);
i2c_start();
i2c_write(0xE1);
i2cVal = i2c_read(0);
i2c_stop();
if (i2cVal == 'B')
output_high(PIN_B5); //read value correct
output_high(PIN_B7); // no stalls
while (1)
{
}
}
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Slave:
| Code: |
#include <18F4550.h>
#device adc=8
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NOBROWNOUT,NODEBUG,USBDIV,PLL5,CPUDIV1,VREGEN, NOPBADEN, ICPRT
#use delay(clock=48000000)
#use i2c(SLAVE, SDA=PIN_B0, SCL=PIN_B1, address=0xE0, FORCE_HW)
#use rs232(baud=115200,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8, errors)
#byte PORTA = 0xF80
#byte PORTB = 0xF81
#byte PORTC = 0xF82
#byte PORTD = 0xF83
#byte PORTE = 0xF84
#byte TRISE = 0xF96
#byte LATB = 0xF8A
#byte TRISB =0xF83
#byte SSPADD = 0xFC8
#byte SSPCON1 = 0xFC6
#byte SSPCON1 = 0xFC6
#bit SSPOV = SSPCON1.6
///////////////////////////////////////////////////////////////////////////////
BYTE address, buffer[0x10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8' };
//////////////////////////////////////////////////////////////////////////////
#INT_SSP
void ssp_interupt()
{
BYTE incoming, state;
state = i2c_isr_state();
if(state < 0x80) //Master is sending data
{
incoming = i2c_read();
if(state == 1) //First received byte is address
{
address = incoming;
}
if(state == 2) //Second received byte is data
{
buffer[address] = incoming;
}
}
if(state == 0x80) //Master is requesting data
{
i2c_write(buffer[address]);
}
SSPOV = 0;
}
//////////////////////////////////////////////////////////
void main()
{
unsigned int8 Buff[16];
unsigned int8 BuffPointer=0;
int16 Val;
int i;
////////// PROCESS ERRATA //////////////
TRISB = 0x00;
LATB = 0x00;
TRISB = 0xFF;
#ASM
MOVF 0xFC9,W
MOVFF 0x40,0xFC9
BSF 0xFC6.4
BCF 0xF9E.3
Lp: BTFSC 0xFC7.0
BRA Lp
MOVLW 0xE0
MOVWF SSPADD
MOVLW 0x36
MOVWF SSPCON1
#ENDASM
/////////////////////////////
setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
//setup_spi(FALSE);
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);
//setup_low_volt_detect(FALSE);
//setup_oscillator(False);
//printf("Hello World\n\r");
enable_interrupts(INT_SSP);
clear_interrupt(INT_SSP);
enable_interrupts(GLOBAL);
//////////////////////////////////////////////////////////////
while (1)
{
}
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Common GND is present + 2 pullups on SDA & SCL
B7 and B5 remain low on the master side!
PCM Programmer, thank you for your help once again. To make things easier, the slave is responding to master [writes] with an offset in the state variable i.e. first byte comes when state=0, 2nd byte comes when state=1 and so on. Also the slave address (E0/E1) is considered as incoming byte when a restart condition is initialted 
Anyway, i'm not able to read from the slave yet.
Thank you |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed May 02, 2007 1:00 pm |
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I've worked on it a little here. I setup two PicDem2-Plus boards --
the master with an 18F452 and the slave with an 18F4550.
I went through some testing, and changed the Slave to a 18F452 and
it worked OK with that setup. The problem is in the 18F4550 as a
Slave. (There may be a problem with it as a Master as well, but
I'm only testing it as a Slave currently).
I tested the Slave 18F4550 with both vs. 3.249 and 4.033 and it fails
on both. The failure mode is that the Master locks up during reading.
It never returns from the i2c code.
I'm running a straight 20 MHz crystal in HS mode. I'm not trying
anything fancy such as running a PLL at this moment. Also, I got rid
of most of your code. I'm using totally striped down test programs.
I also have the rev. A3 silicon on the 18F4550. There are erratas
on the i2c slave operation. I don't think your code fixed those erratas.
I'll have to look at it later, and see if I can add the work-around code.
Maybe then it will work.
If you need to get your project running in the meantime, I would ditch
the 18F4550's. Get something that works. |
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PICoHolic
Joined: 04 Jan 2005
Posts: 224
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| Posted: Thu May 03, 2007 12:18 am |
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Thank you PCM Programmer. I appreciate it.
You're right there are erratas in the A3 revision. i tried to work around using the following code.
| Code: |
TRISB = 0x00;
LATB = 0x00;
TRISB = 0xFF;
#ASM
MOVF 0xFC9,W
MOVFF 0x40,0xFC9
BSF 0xFC6.4
BCF 0xF9E.3
Lp: BTFSC 0xFC7.0
BRA Lp
MOVLW 0xE0
MOVWF SSPADD
MOVLW 0x36
MOVWF SSPCON1
#ENDASM
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in fact the first three ststements need to be placed before the i2c initialization, but i dont know how to do it since CCS is generating i2c init on power up!
It's not working as you just mentioned
I'll keep trying and if there's really something wrong with the 18F4550 i think we should contact microchip to find a solution because it should work! right? I mean 18F4550 has i2c and USB and they should work (both or each alone)
Thank you anyway |
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PICoHolic
Joined: 04 Jan 2005
Posts: 224
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| Posted: Thu May 03, 2007 1:42 am |
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Hello PCM Programmer
Finaaaaaaaalllllllyyyyyyy
It's working
Output | Code: |
state = SSPSTAT & 0B00101101;
State Incoming
09 E0 (expected)
29 00 (expected)
29 42 ('B') (expected)
09 E0 (expected)
29 00 (expected)
0D E1 (here is the unexpected state 0D it should be 0C !!)
2C FF (master reads) (expected)
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Thank you once again.
I feel better now!  |
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Tim Bobbins
Guest
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| final answer |
| Posted: Sun Sep 02, 2007 1:12 am |
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Am I to understand that you got the I2C working by replacing:
state = i2c_isr_state () ;
with:
state = SSPSTAT & 0B00101101;
Can you please post your working code. I am having similar troubles. I have revision A1 of the 18F4420 |
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