shifted bit for spi_read

[globalsys]

Hello.

I've got a problem with the spi_read function.
My master is a pic 18lf4520.
My slave is an integrated circuit which actes as a noise canceller filter.
The communication between this two circuit is good.
I managed to write on the slave'registers, and the slave register answeres correctly.
When I use my scope, I see that all my signals are rigth.
But when I do a printf() of the value returned by the slave, the displayed value is wrong:

1.) On the register there is 0x2e (=0010 1110)
2.) On the scope screen there is 0010 1110
3.) The displayed value is 0x97 (=10010111) => left shifting

my code:
while(1)
{
output_low(DEN_BARRE);
delay_us(1);
spi_write(0x80); //----------------command:read register 0
tmp=spi_read(0);//---------------command:read spi port out
printf("\n\r TMP : %x",tmp);
output_high(COM_VERT);
output_high(DEN_BARRE);
delay_ms(2500);
//tmp=mcu_data_read(0x00);
if(tmp==0x2e)
{
output_low(COM_VERT);
}
}

I would like to know if somebody can advise me. Thanks

Best regards

[ckielstra]

What is your configuration for setup_spi() on both the master and slave?
What is your compiler version?

[Ttelmah]

The 'odds' are that you are reading the data on the wrong edge of the SPI clock, and hence the shift.

Best Wishes

[globalsys]

hello ckielstra.

here comes the description of the spi set up for the pic:

// Hardware SPI :
// - Master mode
// - Data valid when clock goes High to Low
// - SPI clock divide by 64 (115.2 kHz)
setup_spi(SPI_SS_DISABLED);
setup_spi(SPI_MASTER|SPI_H_TO_L|SPI_CLK_DIV_64);

my compiler version:

IDE 3.249
PCB 3.249
PDCM 3.249
PCH 3.249

[globalsys]

hello Ttelmah

I will try to change the front rising for the read.
I will tell tou soon.

Thanks

[globalsys]

Thanks you too, ckielstra

[PCM programmer]

Determine the SPI mode by reading the data sheet for your chip, and
then by looking at the timing diagrams shown on this website:
http://www.totalphase.com/support/articles/article03/#modes

Then set the SPI mode in the setup_spi() function by using ckielstra's
mode settings. It's much easier to do it that way, then to remember
what the CCS or Microchip bit settings mean. Example:
http://www.ccsinfo.com/forum/viewtopic.php?t=31271

[globalsys]

Dear ckielstra, Ttelmah, PCM programmer,

I have foollowed your advises, and I finally managed to get a good answer from my slave.
First I modified the spi setup following the ckielstra method given by PCM programmer, and I modified the edge of the spi clock as Ttelmah said.

Thanks you very much.

You are the best.

Energetic regards