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oni305
Joined: 12 Oct 2010
Posts: 1
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| SPI on 18lf46j11 |
 Posted: Tue Oct 12, 2010 11:27 am |
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Help me please, I have some big trouble using the SPI...
I have a system composed by 1 Master and 2 Slave (all 18lf46j11), a transmission protocol composed of 2 byte (address + value) and separate SlaveSelect.
There is 2 problems:
1) every 2 transmission of the master the slave will freeze until the next transmission (ex: M_tx_indirizzo, M_tx_dato , Slave_works, M_tx_indirizzo, M_tx_dato , Slave_FREEZE, M_tx_indirizzo, M_tx_dato , Slave_works, ecc...)
2) I can't read the data from SLAVE1 
MASTER:
| Code: | #use delay(clock=8000000)
#define SPI_CLK PIN_C3
#define SPI_DI PIN_C4
#define SPI_DO PIN_C5
#use rs232(baud=9600,parity=N,xmit=PIN_B7,rcv=PIN_B6,bits=8)
...
setup_spi(SPI_MASTER|SPI_L_TO_H|SPI_CLK_DIV_4);
...
setup_oscillator(OSC_8MHZ|OSC_INTRC|OSC_31250|OSC_PLL_OFF);
...
output_high(PIN_B0);// SS for slave0
output_high(PIN_B1);// SS for slave1
LOOP:
printf("START (Y,N)? ");
do {
answer=getch();
}
while (answer!='Y'&&answer!='N');
if (risposta=='Y'){
printf("\r\nVado.... \r\n");
//
output_low(PIN_B0);
delay_ms(10);
spi_write(0);
spi_write(vel);
output_high(PIN_B0);
printf("SPEED=%u\r\n",vel);
vel=vel+20;
printf("READ");
output_low(PIN_B1);
delay_ms(10);
spi_write(4);
temp = spi_read(0);
output_high(PIN_B1);
printf("= %u \r\n",temp);
}
else{
printf("\r\nSTOP.... \r\n");
output_low(PIN_B0);
spi_write(0x00);
spi_write(100);
output_high(PIN_B0);
vel=100;
};
goto LOOP;
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SLAVE0: (write only)
| Code: | #use delay(clock=8000000)
#define SPI_SS PIN_A5
#define SPI_CLK PIN_C3
#define SPI_DI PIN_C4
#define SPI_DO PIN_C5
...
#int_SSP
void SSP_isr(void)
{
disable_interrupts(INT_TIMER0);
//receive address
while(!spi_data_is_in());
indirizzo = spi_read();
//write data in position
while(!spi_data_is_in());
dato = spi_read(0);
if(indirizzo >= 0 && indirizzo <= 7)
{
array_valori[indirizzo] = dato;
}
//comandi da eseguire una volta ricevuto il dato
//riabiltare Interrupt
enable_interrupts(INT_TIMER0);
}
...
setup_spi(SPI_SLAVE|SPI_L_TO_H);
....
setup_oscillator(OSC_8MHZ|OSC_INTRC|OSC_31250|OSC_PLL_OFF);
...
LOOP:
goto LOOP;
|
SLAVE1: (Read only)
| Code: | #use delay(clock=8000000)
#define SPI_CLK PIN_C3
#define SPI_DI PIN_C4
#define SPI_DO PIN_C5
#define SPI_SS PIN_A5
...
#int_SSP
void SSP_isr(void)
{
//disabiltare Interrupt
disable_interrupts(INT_TIMER0);
//receive address
while(!spi_data_is_in());
indirizzo = spi_read();
//isend data on SPI: array_valori[indirizzo]
if(indirizzo >= 0 && indirizzo <= 7)
{
while(!spi_data_is_in());
temp = spi_read(array_valori[indirizzo]);
}
else
{
while(!spi_data_is_in());
temp = spi_read(0);
}//se viene passato un indirizzo errato restituisce 0
//comandi da eseguire a fine trasmissione
enable_interrupts(INT_TIMER0);
if(flag2==1){output_high(PIN_B6);}else{output_low(PIN_B6);};//test
flag2 = !flag2;
}
...
setup_spi(SPI_SLAVE|SPI_L_TO_H);
...
setup_oscillator(OSC_8MHZ|OSC_INTRC|OSC_31250|OSC_PLL_OFF);
...
//test
array_valori[0] = 10;
array_valori[1] = 20;
array_valori[2] = 30;
array_valori[3] = 40;
LOOP:
goto LOOP;
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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Ttelmah
Joined: 11 Mar 2010
Posts: 19552
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| Posted: Tue Oct 12, 2010 2:19 pm |
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Also, some comments.
You can only have _one_ oscillator selection in the setup line. Having both 31KHz, and 8MHz, is not legitimate....
Don't bother to disable interrupts in the interrupt handler. Unless you are using high priority interrupts, all other interrupts are automatically disabled by the hardware.
Best Wishes |
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