any shift register(74hc595) example code for nRF52?

[FormerMember]

Hello!

I'm trying to nRF52 soc chip to drive the matrix sensors array (16x16), because there is no enough I/O pins for my project and thinking of use the shift register (74HC595) to drive multiple pins.

Does anyone know how to get the shift register (74HC595) to work on nRF52 or is there have any example code about shift register for nRF51/2?

Thanks.

[bjorn-spockeli]

I am afraid that we do not have any code specific to the 74HC595, but you should be able to use the nRF52s SPI peripheral to clock data in to the 74HC595. I suggest that you take a look at the SPI Master example in the SDK.

In order to clock data into the 74HC595 using the SPI of the nRF52 you have to connect the following pins

74HC595   nRF52
 SRCLK --> SCK 
 SER   --> MOSI
 RCLK  --> SS

Best regards

Bjørn

[FormerMember]

I see two SPI example. SPI Mater and SPI slave? Wondering what's the difference between them? Sorry to ask this question, I'm new to nRF52 DK.

[bjorn-spockeli]

You want the SPI Master example, you want the nRF52 to clock data in to the shift register, not the other way around.

[FormerMember]

Hello! Bjørn, Thanks for response. Just want to know that If we use SCLK for shift register clock, what should we do for the shift register data pin? MOSI, MISO or SS? Thanks

[FormerMember]

@Bjørn If we connect the RCLK and SRCLK together, then the shift register will always be one clock pulse ahead of the storage registe clock. If this is the case, do we still need the SS pin for the SPI on nRF52?

[bjorn-spockeli]

I have not tried that setup, but I guess it depends on how you want to shift the bits in the register. The setup above will send a byte to the SER input of the shift register and then the SS pin will latch the 8 bits. I do not think you will not get the same behaviour if you connect SCK to SRCLK and RCLK.