SPI Testing with ENC28J60

[mikesmixes777]

Hi
I have connected my PIC18LF252 to an ENC28J60 via SPI.

I want to test that the SPI is working. I have written a routine to query one of the ENC28J60 register...but I'm not getting anything back.

Can someone shed any light on the ENC28J60 and its SPI interface...

THanks

unsigned int spi_rxbuf;


void spi_rw(void);
void init_spi(void);


void main(void)

{
	
	TRISA=0b00001011;	//AN0,AN1,AN3 =>Inputs
	TRISC=0b10010000;	//RC7(RX), RC4(SDI) =>Inputs.

	
	init_spi();
	LED1 = ON;


	while(1)
	{
		spi_rw();
	}
}


void init_spi(void)		//Setup SPI comms
{
	SSPSTAT=0b01000000;	//SPI data at middle of output time,
				//Data tx on RISING edge of SCK *ENC28J60
	SSPCON1=0b00100001;	//Fosc/16, SSPEN=enabled, 
}
	

void spi_rw(void)
{
	CS = LOW;		//Start 
	SSPBUF = 0b00011110;	//Read (000) ECON2 at addr 0x1E (11110)
	spi_rxbuf = SSPBUF;
	CS = HIGH;		//Stop
}

 

[felis]

You need till the end of the transfer before reading SSPBUF.

/* writes to SPI. BF is checked inside the procedure */
/* returns SSPBUF	*/ 
BYTE wr_SPI ( BYTE data )
{
 SSPBUF = data;          		// write byte to SSPBUF register
 while( !SSPSTATbits.BF ); 	// wait until bus cycle complete 
 return ( SSPBUF );         //
}

 

[mikesmixes777]

I'm not sure if its working properly now, I'm not sure of the data received back. Are there any constant registers that I can poll in the ENC28J60 that I will know what to expect?

	while(1)
	{
		spi_rw(0x1E);		//0b00011110
		
	}	


char spi_rw(char data)
{
	CS = LOW;
	CS = LOW;			//Start 
	SSPBUF = data;			//Read (000) ECON2 at addr 0x1E (11110
	while (!SSPSTATbits.BF);
	return (SSPBUF);
	CS = HIGH;			//Stop
}

 

[blueroomelectronics]

Why is CS = LOW done twice in a row?

The ENC28J60 has a hardware revision register, or you could try to flash its LEDs.

 

[felis]

I'm not sure if its working properly now

It's not - the 'CS=HIGH' will never execute. Place it before 'return'.

As far as registers - write 0x05 to MACON1 and read it back.

 

[mikesmixes777]

I'm REALLY new to this SPI so you have to exscuse my lack of understanding...

Im trying to get the steps to write to MACON1...

I see MACON1 is in BANK2 & addr 00h (pg12)

Now to select BANK2 I need to write to the ECON1, but when do i actually send 010(op-code) 00000 (addr of MACON1) 00000101 (data) ?

 

[blueroomelectronics]

The ENC28J60 is a tricky chip to use, there is a C library for it that you should use you can download it here.
http://www.ljcv.net/home.html

 

[mikesmixes777]

Ahh... I am actually just on the site at the moment...Thanks for the link...

I came to the conclusion that it is a VERY tricky chip. I been looking thru all the project details at this site and I found that there applications are very indepth, even the mini10T application (http://www.ljcv.net/projects/minipic10t/index.html).

I want to have my own html webpage aswell as log some analog inputs and control digital outputs...but they are running "multi-layer" programs and to see where or how i can add my application and code in seems a nightmare.

Any suggestions...Is there a plain ENC28J60 driver generic for the PIC18F...?

Thanks for the help.

 

[blueroomelectronics]

That is the generic version. Writing an Ethernet stack is no cakewalk.
An ENC28J60 / 18F4620 is likely the next kit coming out from us. I've got a working prototype just working on the "super I/O" part.

 

[mikesmixes777]

I agree that writing an ethernet stack and driver for the ENC28J60 is NOT a cakewalk.

Will I have any luck with my small 18F252? I was thinking of adding a 25LC256 SPI eeprom.

So would your advice be to get my project up and running?
Thanks
Mike