I'm designing a PCB that includes LCD Display NHD-C12832A1Z-FSW-FBW-3V3 (datasheet) connected to the STM32L071KZU6 microcontroller (datasheet).

I'm afraid that the SPI interface of the LCD will not work with the SPI clock from the MCU.

According to the MCU's datasheet, it says that fCLK is 16MHz in SPI master mode while the LCD (the SPI slave) has Tscyc of 50ns -> 20MHz.

Am I correct that this is a problem? How can I make them work together?


Table 71 from MCU datasheet - SPI characteristics


Timing characteristics from LCD module datasheet



1 Answer 1


It's likely that the LCD can work at pretty much any SPI frequency, as long as it is slower than those conditions specified in the datasheet, they're all listed as minimum times. The 16 MHz quoted for the micro is a maximum frequency it can run at, it can also be slower if you desire.

It is fine to use these parts together, and to choose an SPI frequency which suits as long as you don't violate the conditions specified in either datasheet.

  • 1
    \$\begingroup\$ agreed, all those timings in the LCD data sheet are minimums, and no maximum is given, so anything slower than 20 Mhz will work. \$\endgroup\$ Jul 14, 2018 at 21:05

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