MQX SPI chip select problem

pk2 — Tue, 02 Sep 2014 22:58:24 GMT

I am having a problem using the SPI CS signals in my K60 application. My application uses SPI0 and addresses three devices using 3 CS signals (CS0, CS1, and CS2). I read some other posts here and thought I had things working for CS0 and CS1. However CS2 does not toggle when it should. I am using MQX4.1 and CW 10.4.

In my bsp I changed init_gpio.c by modifying case 0 in the _bsp_dspi_io_init function as shown below.

_mqx_int _bsp_dspi_io_init

(

uint32_t dev_num

)

{

SIM_MemMapPtr sim = SIM_BASE_PTR;

PORT_MemMapPtr pctl;

switch (dev_num)

{

case 0:

//Modified Code for 3 chip select SPI0 which is on PORTC of the K60.

/* Configure GPIOC for DSPI0 peripheral function */

pctl = (PORT_MemMapPtr)PORTC_BASE_PTR;

pctl->PCR[4] = PORT_PCR_MUX(2); /* DSPI0.PCS0 */

pctl->PCR[3] = PORT_PCR_MUX(2); /* DSPI0.PCS1 */

pctl->PCR[2] = PORT_PCR_MUX(2); /* DSPI0.PCS2 */

pctl->PCR[5] = PORT_PCR_MUX(2); /* DSPI0.SCK */

pctl->PCR[6] = PORT_PCR_MUX(2); /* DSPI0.SOUT */

pctl->PCR[7] = PORT_PCR_MUX(2); /* DSPI0.SIN */

/* Enable clock gate to DSPI0 module */

sim->SCGC6 |= SIM_SCGC6_DSPI0_MASK;

break;

In my application I open/close the SPI0 port depending upon which of the 3 devices I need to address. Using the below code:

switch (chip_sel)

{

case (0):

ezp_spi_handle = fopen("spi0:1", NULL);

break;

case (1):

ezp_spi_handle = fopen("spi0:2", NULL);

break;

case (2):

ezp_spi_handle = fopen("spi0:3", NULL);

break;

default:

break; //

}

When the application runs, I get a valid file handle for all 3 cases. When "spi0:3" is used, I am expecting CS2 to toggle but CS 1 toggles!!

Are there any examples of how to properly configure a BSP to use more than 2 chip SPI select signals with MQX.

Re: MQX SPI chip select problem

danielchen — Tue, 09 Sep 2014 07:02:31 GMT

I think the index should start from 0 when you fopen the device

case (0):

ezp_spi_handle = fopen("spi0:0", NULL);

break;

case (1):

ezp_spi_handle = fopen("spi0:1", NULL);

break;

case (2):

ezp_spi_handle = fopen("spi0:2", NULL);

break;

Have a great day,
Daniel

Re: MQX SPI chip select problem

pk2 — Thu, 18 Sep 2014 20:48:38 GMT

In "spi0:n", the n is a bit mask that gets shifted into some chip select register. In my case, spi0:1 = CS0, spi0:2 = CS1, and spi0:4 = CS2. When spi0:3 was specified, both CS0 and CS1 are selected. The correct code is

case (0):

ezp_spi_handle = fopen("spi0:1", NULL);

break;

case (1):

ezp_spi_handle = fopen("spi0:2", NULL);

break;

case (2):

ezp_spi_handle = fopen("spi0:4", NULL);

break;

MQX Software SolutionsのトピックRe: MQX SPI chip select problem

MQX SPI chip select problem

Re: MQX SPI chip select problem

Re: MQX SPI chip select problem