Looking for very fast MCU, any advice?

Question

Hello,I am using a PIC18F4620 as an universal "workhorse" in manyapplicationsand I like this MCU because of its versatility and it's easy to use.Recently I am experimenting with an USB-interface chip from FTDI. Thisworks nicebut now I am designing a multichannel ADC at high speed. The problemnow is thatthe MCU is not fast enough to control the ADC-chip, buffer the dataand control theUSB-chip when working at a high througput.Does anybody know about a faster replacement for the the PIC18F4620?Requirements:- about 100 MIPS- easy housing, preferable DIP- built in RAM and ROM- easy (re)flashableAny recommandations?Regards, Teuniz

TT_Man · Accepted Answer

1 processor per channel? 8 pin pic?

teuniz · Answer

How do I interface multiple MCU's to one USB-interface chip(FT245R)??

Because the FTDI-chip has only a 64-byte FIFO and USB can be busy sometimes, I need to buffer the data from the ADC-chip as well. The small PIC's don't have enough RAM.

James Beck · Answer

What amounts of RAM and ROM?100 MIPS is getting near the upper end for an internal memory MCU.Have your looked at the ARMX stuff?How about that Parallax Propellor IC?  8 32 bit MCU's with a built in round robin scheduler.Maybe some of the PIC24 series, may not hit 100 MIPS, but the 16 bitness might make up for that.  Lots of possibilities.  What kind of DAC are you using, interface wise?                    Jim

Scott Seidman · Answer

wrote in news:1172059609.187817.226620An additional PIC to handle USB?-- ScottReverse name to reply

teuniz · Answer

A 4-channel 16-bit ADC, AD974 from Analog Devices connected via SPI.

For the moment, I want to let it run at 10K smp/sec. per channel. So I have to buffer and transfer 80KB/sec. to the FT245R which has an

8-bit wide parallel interface.

I put optocouplers in the SPI-bus because isolation is needed. Because of these opto's the max clockspeed on the SPI-bus is 2.5MHz.

James Beck · Answer

OK, you can get that kind of throughput with SPI. I was just curious. Can you get that kind of continuous throughput over a FT245R? I haven't played with any of those USB bridge parts yet, BUT I am looking at doing a USB project soon and I think one of the off the shelf USB to serial/parallel IC's might just be the ticket.

Jim

Jens Gydesen · Answer

Sounds like a DSP and a USB CPU/JG skrev i en meddelelse news:--------------------------------------------------------------------------------Jeg beskyttes af den gratis SPAMfighter til privatbrugere.Den har indtil videre sparet mig for at få 5501 spam-mailsBetalende brugere får ikke denne besked i deres e-mails.Hent en gratis SPAMfighter her.

Looking for very fast MCU, any advice?

Join the Discussion

Didn't find your answer?