Sending and receiving data through 2 SPI ports

[GVHecke]

Hello,

Is there an example available, or can anyone tell me how I need to configure and use 2 SPI ports of the PIC microcntroller? Each example I find is always for 1 SPI port.

[piort]

hi

Code: Select all

spi1_init(param...)
spi2_init(param...)

happy coding  8) 

[GVHecke]

Thanks,

I will try this. Seems very easy. I asked because documentation stated procedure Spi_Init();
and not spi1_init, spi2_ini

[GVHecke]

SPI1_init() or SPI2_init() does not compile, it gives a compiler error:
Identifier SPI1_init() was not declared.

I have tested this in the SPI example that comes together with micropascal.

So this does not work, any idea how I can make it work?

[jpc]

which PIC are you working with ? It has to have 2 SPI-ports so you must be working on BigPic devboard right?

[piort]

hi,
Like JPC say.... which pic do you use ? at the begining i was thinking you want to use one of those pic with 2 spi ... like the 18f8722... this chip have 2 usart, 2 MSSP so one i2c and one spi OR 2 spi OR 2 i2c ...
The best place to chk if your pic have the hardware you want to use is in the thing call a datasheet

happy coding

[xor]

2 SPI's still seems strange to me. Is there an advantage over a single SPI port? I can understand having multiple I2C and a second MSSP module can help in that case.

[piort]

hi ,

2 spi port = 16 MCP23S17 so 256 more I/O

or 16 of anything in SPI with 3 bit for addressing mode so imagine all the possibility...expander,dac,adc,temp sensor and so on


happy coding

[xor]

That is also accomplished by simply adding single CS lines, whereas a second SPI uses 3 or more pins.

[piort]

hi xor,
that true

btw gratz on your 3000 post

[FRM]

Hi,
The only reason I can think of to justify having more than one SPI port is when you have devices that have wildly different SPI configurations
that will not function with the same SPI_Init paramaters (or compromised with hardware), and you cannot afford lost time in re-initialising
the SPI port between device selects.

Even if you have two devices on two SPI ports, you can still only read one at a time, and lets face it - if you are concerned with real-time data-aquisition
of more than one input with no phase delays (and PIC18F/10MHz SPI data speed is not fast enough) then you'd be better off with multiple PIC's or dsPIC...

[LGR]

if you are concerned with real-time data-aquisition
of more than one input with no phase delays (and PIC18F/10MHz SPI data speed is not fast enough) then you'd be better off with multiple PIC's or dsPIC...

Quite. Which is why I hope they fix the bug on multiple SPI ports with the new release for dsPIC. Last time I tried it, it used SPI 1 regardless of which SPI port was addressed.

Since pretty much all dsPICs and PIC24s have 2 SPI ports, it will become a matter of convenience to use them both. Particularly if you're using SD/MMC or SPI ethernet, you're going to want to dedicate a port to those.

[fryrmnd]

hi. i have also had the problem SPI1_Init() was not declared... i look datasheet and i think that pic24xxx series have 2 SPI modüles... not Pic 18Fxxx... then i want to use pic18... what must be the solution... i will be happy if you can reply... sorry for my bad english...

[jpc]

a simple parametric search at http://www.microchip.com/ParamChartSear ... &pageId=74 will return 82 different p18 chips with 2 SPI modules.
Last post in this thread was allmost 5 years ago, a few things have changed since ...