How can I write 16 bit data using SPI

[slahiri]

<font face="Courier New" size=-1>A) I need to send 000|00000|00011000 using SPI. This is what I wrote, will this work.

void set_voltage (int choice)
{

setup_spi(SPI_MASTER, SPI_H_TO_L , SPI_CLK_DIV_16);
output_low (PIN_C3);
delay_us(30);
if (choice == 1 || choice ==2)
spi_write(24);
spi_write(0)
delay_us(30);
output_high(PIN_C3);

}

b) Can I configure SPI to some other PORTs also other than PORTC, because I need two SPI interface.</font>
___________________________
This message was ported from CCS's old forum
Original Post ID: 12480

[PCM programmer]

<font face="Courier New" size=-1>:=<font face="Courier New" size=-1>A) I need to send 000|00000|00011000 using SPI. This is what I wrote, will this work.
:=
:=void set_voltage (int choice)
:={
:=
:= setup_spi(SPI_MASTER, SPI_H_TO_L , SPI_CLK_DIV_16);
:= output_low (PIN_C3);
:= delay_us(30);
:= if (choice == 1 || choice ==2)
:= spi_write(24);
:= spi_write(0)
:= delay_us(30);
:= output_high(PIN_C3);
:=
:=}
:=
:=b) Can I configure SPI to some other PORTs also other than PORTC, because I need two SPI interface.</font>
---------------------------------------------------------
Your total number of bits is 16, and that's a multiple of 8,
so I think you can use the hardware SPI functions.

However, your sample data shows that you want to send 8 bits
of 0's first. Then it shows 00011000 coming after that.
So your code above is not in the correct order. You need
to change it to put out the 0 byte first. Like this:

spi_write(0);
spi_write(24);

Also, you have this test:
if (choice == 1 || choice ==2)
You need to carefully check which SPI byte should be
affected by that test. Is it the 0 byte or the 0x24 byte ?

-------------------

On your 2nd question:

You can only use the built-in SPI functions with the hardware
SPI port. If you want a 2nd SPI port, you have to do it in
software. For an example, go here, and look at the sample
code for the LTC1298:
<a href="http://www.phanderson.com/PIC/PICC/index.html" TARGET="_blank">http://www.phanderson.com/PIC/PICC/index.html</a>




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</font>
___________________________
This message was ported from CCS's old forum
Original Post ID: 12510