Re: Question about the speed of SPI RAM

On Mar 15, 7:25 pm, Like2Learn <like2le...@xxxxxxx> wrote:
On Mar 14, 5:26 pm, Like2Learn <like2le...@xxxxxxx> wrote:

Hi there,

We found we had to add an external RAM (SRAM or SDRAM) at the late
stage of electrical design. Basically there are only 2 GPIO pins still
available, otherwise the RAM has to share with other peripherals, such
as SPI and I2C. I prefer to connect the external RAM with SPI bus.
However, I am not sure if it is fast enough for RAM read/write. Does
anybody know the typical speed of SPI RAM read/write? Does it meet the
requirement for a device similar to an ethernet switch plus a sensor?
The data collected by the sensor is about 1K bytes per second.
Some background info: The CPU chosen is 32-bit, and can deliver 165
DMIPS at a maximum operating frequency of 100MHz.  Our application
needs 1ms time tick.

Thank you.

Has anybody know any other way to connect the RAM to the processor
with only a few IO pins, and run faster than SPI?


SPI has very low overhead for a given serial bit rate, I would guess