Looking for a 2 dollar uart

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I've been looking for a cheap uart for serial
console/code uploading.  I don't need much,
56k baud, serial or parallel interface.  Don't
suggest MAX3100, it's a decent part but it's
a little too expensive and I'm tired of playing
with Maxim if you know what I mean.

I'm tempted to spin my own, either with extra
cells in a Xilinx CPLD or with a $2.50 PIC.

Any other suggestions?


Re: Looking for a 2 dollar uart
On Fri, 27 Jun 2003 16:38:27 -0700, Jim Stewart

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PIC16F627A, I'd guess.  $2.75 x1 and $1.57 x25, at digikey.

Or, if you can lose some of the pins on the max3100, like the
/rts, /cts, /shdn, and /cs, you *might* be able to get away with
a $1.68 x1 and $1.03 x25 price for the PIC12F629.

     PIC12F629
     _________
  1-|Vcc   GND|-8
    |         |
  2-|DIN  DOUT|-7
    |         |
  3-|SCLK /IRQ|-6
    |         |
  4-|Rx     Tx|-5
     ---------

No idea what you care about there, though.

Jon


Re: Looking for a 2 dollar uart

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PIC12C508 or 12F629 if you want flash and/or interrupts. - should be below $1.50
in quantities more
than a few.
PIC will probably be more flexible than a CPLD, and it may be able to take away
some processing from
the main CPU, e.g. fifo buffering.


Re: Looking for a 2 dollar uart
Hi

The Philips  P87LPC760  14 pin micro with on-board UART
hardware and +-2.5% tolerence RC osc (suitable for some speeds).

Might do the trick

the P87LPC760 is a simple verison of the 80c51 core.

Very cheep - should come close to ~$2. in volume


Just  a thought

JG


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Re: Looking for a 2 dollar uart

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An MSP430 would be smaller, cheaper and take less power. Only 3.3 V, though.

Leon
--
Leon Heller, G1HSM
leon snipped-for-privacy@hotmail.com
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Re: Looking for a 2 dollar uart
Thanks for all the $2 uart suggestions.  I think that
I'll work on the MSP430 approach.



Leon Heller wrote:
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Re: Looking for a 2 dollar uart

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I'd think an 8-pin would probably be a bit cheaper.

Re: Looking for a 2 dollar uart
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Try
http://www.cygnal.com/products/C8051F305.htm

 Claims 99c/10K - and you get UART <-> i2c HW support
( so meets your serial interface) and 256 Bytes of RAM allow large
buffers.
just ignore the 'spare resource' :)
( PCA, analog comparitor, and 1500 bytes of code space)

-jg

Re: Looking for a 2 dollar uart

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Hi Jim,

Well, the UART won't fit in a $2 CPLD.  The UART cores we were looking
at would fit in a 144 macrocell CPLD (CoolRunner if I'm not mistaken).
I think the UART was about 124 macrocells by itself.

Elroy




Re: Looking for a 2 dollar uart
The National Semi stuff (16552) should be priced in that ballpark at
moderate volume (I can get em for ~2.75 in singles), a PIC is good too,
but requires someone to program it - amortize that.

Andrew

Elroy the Seedy Impaler wrote:

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Re: Looking for a 2 dollar uart
 
 >I've been looking for a cheap uart for serial
 >console/code uploading.  I don't need much,
 >56k baud, serial or parallel interface.  Don't
 >suggest MAX3100, it's a decent part but it's
 >a little too expensive and I'm tired of playing
 >with Maxim if you know what I mean.
 >
 >I'm tempted to spin my own, either with extra
 >cells in a Xilinx CPLD or with a $2.50 PIC.
 >
 >Any other suggestions?

 Current CPLD technology is not UART optimal, unless you need
a special case. eg we did a design that needed many cascaded,
TX only, fixed Baud, and for that CPLD was ideal.

 Better would be http://www.cygnal.com/products/C8051F305.htm
They claim 99c/10K, and you have 256 Bytes of RAM for FIFO
buffers, and an i2c BUS.
 Think of it as a MAX3100 with bigger FIFOs and a free uC :)

-jg

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