topic Re: GPIO configuration in Kinetis Microcontrollers

GPIO configuration

ameybhopi — Wed, 24 Dec 2014 06:26:16 GMT

Do we have to configure a pin as gpio in k70 or we can directly use GPIOx_PDDR for io?

Re: GPIO configuration

xiangjun_rong — Wed, 24 Dec 2014 09:27:13 GMT

Hi, Amey

It is dependent on what you use the GPIO pin, if you use the GPIO pin to output signal, this is the procedure:

1)enable the GPIO module clock in the SIM_SCGC5 register, for example, enable PORTA by setting the PORTA bit in SIM_SCGC5

2)configure the MUX bits in PORTx_PCRn register based on the section 10.3.1 K70 Signal Multiplexing and Pin Assignments in reference manual of k70

3)set the corresponding bit in GPIOx_PDDR register to enable GPIO output mode

4)you can set/clear the GPIO pin by writing GPIOx_PDOR.

If you read the logic of the GPIO pin, after you enable the GPIO port clock, I think you can read the pin directly by reading the GPIOx_PTOR register. I think It is okay to set the GPIO pin in GPIO mode by writing the PORTx_PCRn register as above procedure, clear the bit in GPIOx_PDDR register, then read GPIOx_PDIR register to get the pin logic.

Have a nice festival

XiangJun Rong

Re: GPIO configuration

ameybhopi — Wed, 24 Dec 2014 10:39:34 GMT

Hi Xiang I am very new to k70 microcontroller I want to make PTC4 pin as

input to receive digital data fron a device. I have written in this way

GPIOC_PDDR&=(1ul<<4) and then read 4th bit USING GPIOC_PDIR

Is this correct?

On Wed, Dec 24, 2014 at 2:57 PM, xiangjun.rong <

Re: GPIO configuration

yasuhikokoumoto — Thu, 25 Dec 2014 01:59:03 GMT

Hi Amey,

according to XiangJun's direction, you should take the following procedure.

(1) SIM_SCGC5 |= (1<<11); // PORTC Clock Enable
(2) PORTC_PCR4 &= ~(7<<7); // set PORTC4 MUX to 000 (disable)
PORTC_PCR4 |= (1<<7); // set PORTC4 MUX to 001 (GPIO)
(3) GPIOC_PDDR &= ~(1<<4); // set GPIOC4 input

Then, you can get PTC4 input data from GPIOC_PDIR[4].

Best regards,
Yasuhiko Koumoto.