Em 3/2/2010 17:44, Jan-Erik Soderholm escreveu: > > Isaac Marino Bavaresco wrote: > = >> Em 3/2/2010 16:58, Jan-Erik Soderholm escreveu: >> = >>> Dwayne Reid wrote: >>> = >>> = >>>> Good day to all. >>>> >>>> I'm about to look at a project where I need to communicate with 3 = >>>> serial devices. All 3 ports will be communicating at 38,400 = >>>> baud. Although all three ports need to be able to receive data = >>>> simultaneously, transmission can be to one device at a time. >>>> >>>> I see that some of the larger (16-bit) PICs have up to 4 UARTs on = >>>> board. However, I haven't used those devices yet and don't have a C = >>>> compiler for them. >>>> >>>> I recall discussion in the past where people have used external UARTs = >>>> with 16F PICs, connected via SPI or I2C. Can someone remind me of = >>>> what those UARTs were? >>>> >>>> The largest packet size appears to be less than 16 bytes. It would = >>>> be cool if these external UARTs had at least a 16-byte receive buffer. >>>> >>>> = >>>> = >>> Here is one with 128 byte send and rec buffers : >>> http://www.maxim-ic.com/quick_view2.cfm/qv_pk/6463 >>> = >>> = >> At $4.00/unit @ 1k, it is more expensive than most PIC24 with 4 UARTs. >> Adding the cost of the MCU, it becomes more expensive than a PIC32 with >> 6 UARTs. >> >> >> Regards, >> >> Isaac >> = > There was no mention about price limit, but a larger > send/receive buffer *was* mentioned. > > Anyway, noone else then Dwayne knows the tradeoffs in > this project... :-) > = He wants a large buffer because the UART would be off-chip. With the on-board UART, all the MCU's RAM may become a buffer, just use an interrupt-driven receive routine and a circular buffer. Isaac __________________________________________________ Fa=E7a liga=E7=F5es para outros computadores com o novo Yahoo! Messenger = http://br.beta.messenger.yahoo.com/ = -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist