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Olufola
Joined: 19 May 2009
Posts: 21
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| Sensor Network with I2C |
 Posted: Tue May 19, 2009 1:44 pm |
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I am currently working on a project involving sensor network. Eleven PICs are to be used in the network. I have been trying to use I2C to implement the network in such a way that I have ten slaves and one master. The whole idea is to have ten discrete sensors (slaves) communicating with central base station (master).
Addressing the slaves has been a big problem. I can only broadcast on the network. I cannot uniquely request for data from individual slaves. I saw somewhere that no one has ever successfully implemented correct addressing with the CCS compiler. I do not know if this is true or not.
Assembly code was said to have worked. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue May 19, 2009 2:18 pm |
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| Quote: | | Addressing the slaves has been a big problem. |
1. Post the PIC that you are using for the slaves.
2. Post the #use i2c() statement for a few of the slaves, so we can see
the addresses that you are using.
3. Post your compiler version. |
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Olufola
Joined: 19 May 2009
Posts: 21
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| Posted: Tue May 19, 2009 2:37 pm |
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Thanks,
1. I am using PIC18F4520 for all the slaves and the master.
2. #use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=104)
3. I am using PCW.
I will soon post the full slave and master code.
Once again, Thanks |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue May 19, 2009 2:56 pm |
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| Quote: | | 2. #use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=104) |
Post several of the #use i2c() statements for your slaves, so I can see
the slave address on each one. |
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Olufola
Joined: 19 May 2009
Posts: 21
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| Posted: Tue May 19, 2009 3:51 pm |
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I mistakenly posted a reply without logging in. My last reply was attributed to a guest. Some of the slave #use are:
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=97)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=98)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=99)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=100)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=101)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=102)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=103)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=104) |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue May 19, 2009 3:55 pm |
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| Quote: | #use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=97)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=98)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=99)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=100)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=101)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=102)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=103)
#use i2c(Slave,Slow,sda=PIN_C4,scl=PIN_C3,force_hw,address=104) |
The slave addresses shown in bold are not correct. The slave addresses
must be an even number. |
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Olufola
Joined: 19 May 2009
Posts: 21
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| Slave address |
| Posted: Wed May 20, 2009 2:16 am |
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I tried using two slave PICs just to ensure that the addressing problem is solved before using ten. The following is the Master code that I wrote. The problem with this is that data is received from the first slave after with the nothing else happens (as if the program hangs). These were the first codes I used and the crap that I posted yesterday were the ones that I resorted to when this one that I originally expected to work did not ( I have not joined this forum then anyway)
I will be glad anyone can help me scrutinize this code for any errors. I might be biased.
| Code: |
#include <18F4520.h>
#device adc=8
byte stad,gook;
#FUSES NOWDT //No Watch Dog Timer
#FUSES WDT128 //Watch Dog Timer uses 1:128 Postscale
#FUSES HS //High speed Osc (> 4mhz)
#FUSES NOPROTECT //Code not protected from reading
#FUSES NOBROWNOUT //No brownout reset
#FUSES BORV25 //Brownout reset at 2.5V
#FUSES NOPUT //No Power Up Timer
#FUSES NOCPD //No EE protection
#FUSES NOSTVREN //Stack full/underflow will not 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 NOIESO //Internal External Switch Over mode disabled
#FUSES NOFCMEN //Fail-safe clock monitor disabled
#FUSES NOPBADEN //PORTB pins are configured as digital I/O 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)
#use delay(clock=20000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
#use i2c(Master,fast,sda=PIN_C4,scl=PIN_C3,force_hw)
void main()
{
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF|ADC_TAD_MUL_0);
setup_psp(PSP_DISABLED);
setup_wdt(WDT_OFF);
setup_timer_0(RTCC_INTERNAL);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
setup_comparator(NC_NC_NC_NC);
setup_vref(FALSE);
//Setup_Oscillator parameter not selected from Intr Oscillotar Config tab
// TODO: USER CODE!!
i2c_start();
delay_ms(5);
i2c_write(0xc1);
delay_ms(5);
while(true)
{
i2c_start();
delay_ms(5);
stad = i2c_isr_state();
if(stad==0 ||stad==0x80){ printf("Address Match Received From Slave 1 \n\r"); }
gook = i2c_read();
delay_ms(5);
printf("Received Data from slave 1 is %3u\n\r",gook);
output_high(pin_d6);
delay_ms(50);
output_low(pin_d6);
delay_ms(50);
delay_ms(100);
//------------------------
i2c_start();
delay_ms(5);
i2c_write(0xd1);
delay_ms(5);
stad = i2c_isr_state();
if(stad==0 || stad ==0x80)
{ printf("Address Match Received From Slave 2 \n\r"); }
gook = i2c_read();
delay_ms(5);
printf("Received Data from slave 2 is %3u\n\r",gook);
output_high(pin_d4);
delay_ms(50);
output_low(pin_d4);
delay_ms(50);
//--------------------
}
i2c_stop();
delay_ms(10);
} |
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Ttelmah
Guest
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| Posted: Wed May 20, 2009 10:04 am |
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The obvious thing is that you never 'stop' the first transaction.
A repeated 'start', is legitimate on a single I2C device, normally used as a way of switching bus direction, but a repeated start, with a device already selected?....
I2C, needs care on a number of things.
Make sure you ack/nack as required on data transfers. Failing to switch for the last byte, is a common error.
Stop, when you have finished.
Best Wishes |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed May 20, 2009 11:16 am |
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This is supposed to be the i2c Master program, but it's full of code
for the slave program. It has calls to i2c_isr_state(), but that routine
is supposed to be called inside a slave interrupt routine.
I suggest that you start over. Try to make small Master and Slave
test programs. Get those programs working. Then expand the code.
Here is how to do it:
Use the CCS example file code, Ex_Slave.c, for the Slave PIC.
It's in this directory:
Quote:
c:\Program Files\picc\Examples\Ex_Slave.c
Use the code in this post for the Master PIC:
http://www.ccsinfo.com/forum/viewtopic.php?t=32368&start=3
See if you can make that test work. |
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