MSP430FR2155: Maximum clock frequency we can get from a GPIO pin

Hi Balaji,

According the FR2155 datasheet, the maximum SPI clock rate is 8MHz, even though the GPIO pins can be clocked faster than this, so you are limited to 8MHz.

Dennis Lehman said:

According the FR2155 datasheet, the maximum SPI clock rate is 8MHz, even though the GPIO pins can be clocked faster than this, so you are limited to 8MHz.

CPU need minimum 3 CPU clocks (one assembler instruction) for port write. In case with devices running on 24 MHZ it can't go faster than 8 MHz. It is possible to do it in 2 CPU cycles with DMA, but AFAIK there is no DMA in FR2xx family.

Thank you for the response,

Is it required to program clock frequency to GPIO port seperately or will it automatically takes the system clock frequency.

If we need to program means, Can you provide a sample code for configuring 8MHz Clock frequency to GPIO port pins(specifically P1.5, this is my clock pin).

Thank you.

If for transfer is used hardware peripheral module, than module clock should be selected, and than clock signal on pin (if exists) is generated by peripheral.

If it is bit banging / software based, than MCLK CPU instruction define timing. In this case for clock signal on pin (if it is constant) can be used timer to release CPU bandwidth.

Hi Balaji,

It's been a while since we have heard from you, so I'm going to assume you were able to move forward with your project.
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Hello Dennis,

Sorry for the late response, I was testing with some other methods. But I am unable resolve the issue. My doubt is can we set the clock frequency to GPIO Peripheral as we do it for other peripherals like UART,SPI, etc. If we can set means how can we do that.

I am implementing SPI communication using GPIO pins(without configuring SPI driver). The implementation is working fine as I can send data. But clock frequency is the main issue I am facing. I have configured GPIO P1.5 as the clock pin and now I want to generate minimum of 1MHz clock. How can I achieve this??

Thank you.

Hello zrno soli,

Sorry for the late response, I was testing with some other methods. But I am unable resolve the issue. My doubt is can we set the clock frequency to GPIO Peripheral as we do it for other peripherals like UART,SPI, etc. If we can set means how can we do that.

I am implementing SPI communication using GPIO pins(without configuring SPI driver). The implementation is working fine as I can send data. But clock frequency is the main issue I am facing. I have configured GPIO P1.5 as the clock pin and now I want to generate minimum of 1MHz clock. How can I achieve this??

Thank you.