topic Re: Re: Has anyone coded up a bit banged SPI driver for a L series device? in Kinetis Microcontrollers

Has anyone coded up a bit banged SPI driver for a L series device?

clivepalmer — Thu, 29 May 2014 14:32:10 GMT

I am using a KL02Z device which only has a single SPI port. I require to use two and hence I need to code up a bit bashed SPI driver.

Before I spend time coding and debugging this, is there anyone out there who has already coded one up that they would be so kind as to share?

Thanks

Re: Has anyone coded up a bit banged SPI driver for a L series device?

perlam_i_au — Fri, 30 May 2014 22:06:59 GMT

There is not an specific driver for KL02Z, but you can use as base the SPI driver for KL05 (attached).

Have a nice day,
Perla Moncada

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Re: Re: Has anyone coded up a bit banged SPI driver for a L series device?

mjbcswitzerland — Sat, 31 May 2014 00:45:03 GMT

Clive

I use this code to bit bang to EZPORT of other devices. There is no difference between K and KL GPIO port code.

- The ports need first to be configured as inputs or outputs before use.

- the clock phase matches the EZPORT so may need to be adjusted for certain SPI slaves

- port used and ports bits may need to be changed to suit

- whether setup and hold delays are required depends on your CPU speed and the SPI slave's speed. I needed 1us delays for the EZPORT to work when using the code on 100MHz devices because the GPIOx_PSOR and GPIOx_PCOR operations are pretty fast.

#define EZRESETOUT	PORTD_BIT15	// port output for reset signal
#define EZCSOUT	PORTD_BIT11	// SPI2_SC0
#define EZDIN	PORTD_BIT13	// SPI2_MOSI
#define EZDOUT	PORTD_BIT13	// SPI2_MISO
#define EZCLKOUT	PORTD_BIT12	// SPI2_CLK

// Send and receive a single byte

static unsigned char fnSendEZPORT(unsigned char ucDataOut)

{

	unsigned char ucBit = 0x80;	// data sent and receive most significant bit first
	unsigned char ucReadByte = 0;
	do {
	GPIOD_PSOR = EZCLKOUT;	// generate rising clock edge
	fnDelayLoop(1);
	if (ucDataOut & ucBit) {	// set new data output state
	GPIOD_PSOR = EZDOUT;
	}
	else {
	GPIOD_PCOR = EZDOUT;
	}
	fnDelayLoop(1);
	GPIOD_PCOR = = EZCLKOUT;	// falling clock edge
	fnDelayLoop(1);
	GPIOD_PSOR = EZCLKOUT;	// rising clock edge
	if (GPIOD_PDIR & EZDIN) {	// read data in
	ucReadByte \|= ucBit;
	}
	ucBit >>= 1;
	} while (ucBit != 0);
	return ucReadByte;

}

Regards

Mark

Re: Re: Has anyone coded up a bit banged SPI driver for a L series device?

clivepalmer — Mon, 09 Jun 2014 06:31:35 GMT

Hi,

Thanks you both for taking the time to reply and sorry for my late response. This help is much appreciated.