SPI problem with PIC18F4520

[sven_1669]

I am trying to use SPI interface to connect to the STA013 mp3 decoder IC. It looks like it sends the first byte, but then it stops sending the data.
Any ideas???


int8 const mp3[10032]= {0xFF,0xE3,0x10,0xC0,0x00,0x09,0x48,0x02,
0xE3,0xAF,0x40,0x00,0x02,0x96,0x39,0x3E,
0xA0,0x1C,0xDB,0x78,0x93,0x28,0x34,0x31,
0x86,0x04,0x9E,0x73,0x04,0x25,0x38,0x3F,
0xFE,0x18,0xE5,0x1D,0x54,0x31,0xE7,0x22,
0x03,0x9E,0x5F,0xA8,0x1F,0xE5,0xCF,0xD7,
0x0F,0xF5,0x80,0x04,0xFF,0xE3,0x10,0xC0,
0x01,0x09,0xE0,0xE3,0x1F,0x1F,0x81,0x39,
0x02,0x00,0x3D,0x04,0xD0,0x4E,0x04,0x00,
0x00,0x00,0x0A,0x0D,0x0B,0x85,0xC0,0x03,
0xFF,0xE7,0xF4,0x5F,0xD5,0x26,...........};

long int j=0;

void mp3_out()
{
while(j<10032)
{
if (input(PIN_B6))
{

output_a(0x01);
delay_ms(100);
output_b(0x00);
delay_ms(100);
spi_write (mp3[j]);
++j;
}

else if (!input(PIN_B6))
{
output_a(0x02);
delay_ms(100);
output_a(0x00);
delay_ms(100);
}
}
}

void main()
{
setup_spi(SPI_MASTER|SPI_L_TO_H|SPI_CLK_DIV_4);
output_b(0x80);
call_i2c_init();
call_sta013_bin();
mp3_out();

}

[PCM programmer]

You are reading Pin B6 then you turn around and whack the whole of
Port B by writing all zeros to it. What device is connected to pin B6 ?
What happens to its output pin when you drive it to a Logic zero from
the PIC ? I don't know. It might not be good.

The 2nd thing is, you've got a 200 ms delay on all spi write operations.
So take 10K and divide it by 5 and you get 2000 seconds to send all
your data. That's over 30 minutes. This will give the appearance
that your program has "locked up".

Finally, you didn't say if you're using a debugger, but if you are,
the debuggers use pins B6 and B7. You can't use them in your
own program while using the debugger.

[sven_1669]

pin b6 is the data_req pin from the sta013. When it is high, the decoder wants more data. I will try not setting it all to zero's, and see what that does. Also, I am not using a debugger, so that would not be causing the problem.

[sven_1669]

I changed the code from

[PCM programmer]

It appears that you're trying to create a driver for the STA013 chip.
My advice is to find an existing driver on the net and convert it to CCS.

[ckielstra]

The STA013 chip is very versatile which makes it difficult to program, the code for initialising the chip is missing so we can't tell you are configuring the SPI interface correctly. At first glance it looks OK, but how are you handling the BIT_EN line? Is DATA_REQ configured to be active high or low and is SKCR sampled on the rising or falling edge? Etc...

I agree with PCM Programmer, many projects using this chip exist on the internet so you would make life a lot easier on yourself by porting one of those projects.

[sven_1669]

alright....thanks for the help....back to the head scratching....