topic Re: Kinetis K70 as I2C-Slave in Kinetis Microcontrollers

Kinetis K70 as I2C-Slave

andy87 — Mon, 24 Sep 2012 13:59:13 GMT

Hallo,

I have a problem to configure the Kinetis K70 as a I2C-Slave.

My Master send the Slave-address but I get always a NACK from my K70.

I have a short example to check the Slave-address.

Here my configuration:

SIM_SCGC4 |= 0x40; //Turn on clock to I2C0 module

PORTE_PCR19 = PORT_PCR_MUX(4); // SCL

PORTE_PCR18 = PORT_PCR_MUX(4); //SDA

I2C0_A1 = 0x6;

// Slave-address

I2C0_C1 |= I2C_C1_IICEN_MASK;

/* enable IIC */

I2C0_C1 |= I2C_C1_IICIE_MASK;

// interrupt enable

I2C0_C1 &= ~0x10;

I2C0_C1 &= ~I2C_C1_MST_MASK;

At the moment i have only an ISR, which toggels LED's if the Slave address is correct.

void i2c0_isr (void)

{

GPIOA_PDOR &= ~GPIO_PDOR_PDO(GPIO_PIN(11));

GPIOA_PDOR &= ~GPIO_PDOR_PDO(GPIO_PIN(10));

I2C0_S |= 0x2;

}

I dont know where my mistake is. Have anyone an idea??

Could it be a timing problem?

Re: Kinetis K70 as I2C-Slave

DavidS — Mon, 24 Sep 2012 18:10:51 GMT

Hi Andreas,

Please make sure you are enabling the interrupt at all levels:

- module (as you've done in your application)

- NVIC (ex: enable_irq(30); don't forget to set the priority too: set_irq_priority (int irq, int prio); )

- core (#define EnableInterrupts asm(" CPSIE i"); )

Regards,

David

Re: Kinetis K70 as I2C-Slave

andy87 — Tue, 25 Sep 2012 06:54:10 GMT

Hi David,

Thank u for your answer.

I enabled the interrupts as u discribed. I just set no priority, because this is my only interrupt in my testing-program right now.

But I saw that the program run into the isr_default-Interrupt if i wanna set the slave address and the Port-Control-Register to change the GPIO to SDA-functionalty.

It returns then back to the main, but I have no idea why the program jump into the ísr_default.

So I think the program set not really my SDA-Port and my Slave-Address.

Regards,

Andy

Re: Kinetis K70 as I2C-Slave

andy87 — Tue, 25 Sep 2012 08:11:04 GMT

Problem is solved:).

My mistake was that I turned on all port clocks after the I2C-Init.

I make it now before the Init and the problem is away.

Best Regards,

Andy

Re: Kinetis K70 as I2C-Slave

DavidS — Tue, 25 Sep 2012 14:01:35 GMT

Hi Andy,

Thanks for sharing the solution.

Congratulations!

Regards,

David