Fastest bus/peripheral on LPC55?

[dav1]

Hi,

I need to wire a LPC55 to another (more beefy) application processor.

What would be the absolute fastest peripheral available on the LPC55-series?
(except 480mbit HS USB that is)

thanks!

[dav1]

thanks! good input. we might need to use LPC55 series so no EMC there
an alternative would be SDIO/MMC with 4-8 data-pins running at DDR speed, any LPC's that supports this?

we could consider RT-series too, like imxrt 500/600 or rt1062

[dav1]

Hi,

So quad-SPI = 200Mbit would be the fastest using spi right?

About your parallel option, what is the fastest gpio speed we can reach?
does that support DMA? Any examples?

[xiangjun_rong]

Hi,

As you know that the LPC55xx only supports normal SPI rather than 4 data pins SPIFI.

I suppose that the fastest GPIO toggling can reach up to 50MHz, because you have to simulate the /RD, /CS signal, so I suppose that DMA is not supported.

BR

XiangJun Rong

[xiangjun_rong]

Hi,

Unfortunately, the LPC55xx do not have SPIFI module, it only has general SPI module. For the GPIO pin simulation to access the memory, we have not example. In order to save cycles, I suggest you use assembly language to access the GPIO registers. I do not think you can use DMA.

As am alternative, you can consider a LPC processor with EMC for example LPC54628, which can access external  dual port SRAM or FIFO with EMC module directly.

Hope it can help you

BR

XiangJun Rong

[xiangjun_rong]

Hi, David,

I think you have several options, first of all, you can use the serial interfaces such as SPI, I2S, I think that the SPI bit clock can reach up to 50MHz as master, can reach up to 25MHz as slave. For the I2S, the bit clock can reach up to 6.144MHz.

As an alternative, I suppose that you can use parallel transfer, for example, you can use an external FIFO, on the LPC55XX side, you can use one group GPIO port as data bus, another group GPIO as control signal, you can access data to/from FIFO.

Hope it can help you

BR

XiangJun Rong