Hi I want to give 12 input signal (with 40Mhz for each one) to lpc1788 gpio pins what is the maximum frequency of input signal can we do to lpc1788 gpio pins Can we use SSP for get these signals
Sorry but I'm pretty sure that is too fast.
First off - consider how many instructions you have time to execute in 40 MHz, i.e. 25 ns. Next thing is that the GPIO need to interface with the processor core too.
SSP? The datasheet clearly shows what max frequency you can use for a SSP slave - and I think the chip allows max 1/12 of core frequency as max SPI speed. But SSP is synchronous and only takes one single bit as input. So you need a 40MHz clock and can only feed one of your 12 signals to a SPI interface.
How come you didn't write a single sentence trying to tell what problem you are trying to solve?