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micman2
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| VS1011 the code SPI is correct? |
 Posted: Fri Feb 23, 2007 2:37 am |
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Hi,
I have a problem with VS1011 and PIC 18F452, the code is correct for SPI?
| Code: |
set_tris_a(0x11);
set_tris_b(0x11);
set_tris_c(0x90);//
set_tris_d(0x67);
set_tris_e(0x00);
output_high(CS_VS1011); // DISABLE CS VS_1011
output_low(BYSYNC_VS1011); // DISABLE BYSYNC VS_1011
output_bit(RESET_VS1011,1);
delay_ms(10);
output_bit(RESET_VS1011,0); //reset
delay_ms(10);
output_bit(RESET_VS1011,1);
Delay_ms(100);
while(!input(DREQ_VS1011) == 1);
output_bit(CS_VS1011,0); //Hardware Reset logical level to 0-->1
delay_ms(10);
Spi_Write(0x02); //Command for write 0x(02)
Spi_Write(0x00); //ar register 0x00
Spi_Write(0x08); //Set mode register
Spi_Write(0x02); //is 16bit long
delay_ms(10);
output_bit(CS_VS1011,1); //Hardware Reset logical level to 0-->1
Delay_us(30); //attesa per l'esecuzione basta controllare lo stato di DREQ
output_bit(CS_VS1011,0); //Hardware Reset logical level to 0-->1
Spi_Write(0x02); //
Spi_Write(0x03); //Set the register for the clock
Spi_Write(0x98); //I use a doubler PLL whit 12.288Mhz
Spi_Write(0x00); //
output_bit(CS_VS1011,1); //Hardware Reset logical level to 0-->1
Delay_us(30);
// ------------------------------------------------------------------- NOW IF SEE YHE VS1011 it answers
while(!input(DREQ_VS1011) == 1);
output_low(CS_VS1011); // xCS low attiva
delay_ms(10);
spi_write(0x03); //READ STATUS REGISTER
spi_write(0x01);
a1=spi_read(); // a1 and b1 = 0 !!!!!! <<<------ error not response
b1=spi_read();
delay_ms(10);
output_high(CS_VS1011);
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I set the MODE register and the clock but when I check if the VS1011 is set ok and if VS1011 response correctly , the VS1011 not response!!! a1 and b1register is set always 0 , any registry I read of VS1011!!.
The code is correct for read?
spi_write0x03); //READ STATUS REGISTER
spi_write(0x01);
a1=spi_read(); // a1 and b1 = 0 !!!!!! <<<------ error not response
b1=spi_read();
delay_ms(10);
output_high(CS_VS1011); |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Fri Feb 23, 2007 2:52 am |
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| SPI is a full duplex bus, you send and receive data at the same time. A gotcha on the CCS spi_read() function is that calling this function without parameters will return you the last received value (no SPI clock pulses are generated). If you want to receive a new byte you will have to transmit a byte simultaneously, hence pass a parameter to spi_read(). Check the VS1011 datasheet if you have to send a 0xFF or 0x00 when reading data. |
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Guest
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| Posted: Fri Feb 23, 2007 2:59 am |
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| ckielstra wrote: | | SPI is a full duplex bus, you send and receive data at the same time. A gotcha on the CCS spi_read() function is that calling this function without parameters will return you the last received value (no SPI clock pulses are generated). If you want to receive a new byte you will have to transmit a byte simultaneously, hence pass a parameter to spi_read(). Check the VS1011 datasheet if you have to send a 0xFF or 0x00 when reading data. |
Ok thanks you for your answer .
but before I must control (read) and address (register)
spi_write0x03); //READ
spi_write(0x01); //Address
then I read ....... mistake ? |
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Ttelmah
Guest
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| Posted: Fri Feb 23, 2007 3:24 am |
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OK.
Once you have clocked 'out' these two bytes, you need to clcok 'in' the returned data. Clocks are only generated, when a byte is sent. So, you can either do:
| Code: |
spi_write0x03); //READ
spi_write(0x01); //Address
//At this point, the 'read' register, will contain a garbage byte
//clocked 'in', while the address was being transmitted.
spi_write(0); //Clock out a _dummy_ byte to get the data back
val=spi_read();
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or:
| Code: |
spi_write0x03); //READ
spi_write(0x01); //Address
val=spi_read(0); //This automatically clocks 'out' the dummy '0'
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It is a bit of an 'annoyance', in the way the CCS SPI functions work, relative to this full duplex bus, with the spi_read function, behaving in two different ways.
Personally, I use my own SPI functions, rather than the CCS ones, since when operating in interrupt driven mode, the CCS functions do not really allow the hardware to be comfortably operated...
Best Wishes |
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micman2
Guest
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| Posted: Fri Feb 23, 2007 4:11 am |
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| Ttelmah wrote: | OK.
Once you have clocked 'out' these two bytes, you need to clcok 'in' the returned data. Clocks are only generated, when a byte is sent. So, you can either do:
| Code: |
spi_write0x03); //READ
spi_write(0x01); //Address
//At this point, the 'read' register, will contain a garbage byte
//clocked 'in', while the address was being transmitted.
spi_write(0); //Clock out a _dummy_ byte to get the data back
val=spi_read();
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or:
| Code: |
spi_write0x03); //READ
spi_write(0x01); //Address
val=spi_read(0); //This automatically clocks 'out' the dummy '0'
|
It is a bit of an 'annoyance', in the way the CCS SPI functions work, relative to this full duplex bus, with the spi_read function, behaving in two different ways.
Personally, I use my own SPI functions, rather than the CCS ones, since when operating in interrupt driven mode, the CCS functions do not really allow the hardware to be comfortably operated...
Best Wishes |
Ok , Now work!!
I thought that the clock he generated it in automatic
output_low(CS_VS1011); // xCS low attiva
spi_write(0x03);
spi_write(0x01);
a1=spi_read(0);
b1=spi_read(0);
output_high(CS_VS1011); // |
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