GPIOs pins to be set to send command

Hi everyone,

for a project, we need to interface an analog sensor which is not using standard protocols like I2C or SPI.

Instead, it uses 6 pins to receive commands. So, if I need to send for example command 0x24, I need to set this value on the 6 GPIOs. 

I found an older discussion where a solution to this problem was proposed using some pins (discussed here) but since I am 

forced by design to use pins P1.01-P1.06 I am getting a warning from Segger Embedded Studio compiler "left shift count >= width of type".

My code is simply the following

void writeCommandPort(uint8_t value)
    uint32_t pin_mask = 0xF << SENSOR_FIRST_PIN;
    NRF_GPIO->OUT = (NRF_GPIO->OUT & ~pin_mask) | (value << SENSOR_FIRST_PIN);  


Can someone help me understanding what I am doing wrong?

Thanks a lot!