Hi,

I want to know that what is the maximum speed of SPI interface?

How many devices we can connect maximum practically on the SPI and I2C interface ?

Thanks
Ash

 

Look up the specs for the SPI interface on the device you want to use.

 

Kind of like asking "how fast can a car go?"

Depends on the car, and the road.

 

ya ofcourse but like i2c we have maximum 5MHz ulta fast mode so same as in spi is there any maximum speed ?

 

ya ofcourse but like i2c we have maximum 5MHz ulta fast mode so same as in spi is there any maximum speed ?

NO.

The maximum attainable speed with SPI depends entirely on the capabilities of the host microcontroller and the peripheral device with which it is communicating. Some very slow devices may not be able to handle more than a few MHz, while others may be able to clock at up to 50 MHz or even more.

But there is no "official" limit on speed for SPI, nor any "standard" speed.

 

hi 123,
I have a 18F4520 with an external 20MHz xtal, with PLL set to *4, so Fosc =80MHz.
Divided down by the PIC, it is clocking the SPI at 20MHz, confirmed by a scope.

The SPI is driving a 2.2inch TFT LCD 9225, very fast updates.

E

Excuse poor quality video

 

There is the max speed of the SPI interface (raw hw clock speed) and the max speed of computer data transfers between processes on the computer.
https://forum.allaboutcircuits.com/threads/fifo-logic-block-meta-stability.136284/#post-1143241