Realtime 32x8k lookup table operation with PICBASIC PRO and PIC hardware possible?

[CuriousOne]

Hello.

Say the following situation.

We have 8 tables, 32k size each.

The incoming signal bursts 32768 samples in about 100msec.

Our task is, identify by first 64 byte the incoming signal, and output data from apropriate table, synced with input signal.

Is this possible?

[HenrikOlsson]

Hi,
I'm not going to tell you that it's doable and I'm not going to tell you that it's not but lets take a look at it.
The first issue, obviously, is memory. There's no 16F or 18F PIC available with >256kB memory, I think the most memory you can get in the 8bit ones is 128kB - so you're going to need an external memory of some sort.

The easiest to deal with probably is a SPI interfaced FLASH memory of some sort. They are cheap, available in a large array of sizes and they are cheap. EDIT: Did I say they are cheap ;-)

If the input and output "signals" are "random", ie the output values can not be retreived sequentially from the memory you're going to have to transfer perhaps 5 bytes to the memory to get 1 byte back - a total 40bits. Then you're going to have to do that 327680 times per second for a total average bitrate of 1.3Mbit / second. In reallity you're going to run the SPI faster than that - which is doable with the SPI peripheral in the PIC.

I have a feeling it might be doable but it obviously depends on what else the PIC needs to do. How are the "samples" ie. the index pointer for the lookuptable getting into the PIC?

More details please?

/Henrik.

[Aussie Barry]

WOW Henrik!
The depth of your knowledgeable responses never ceases to amaze.
The same applies to all the other regular contributors to this forum.
Your on-going help to resolve my PIC issues is greatly appreciated.
To all of you, thank you so much.

Merry Christmas to you all.

Cheers
Barry
VK2XBP