- Looking for a 2 dollar uart
- Posted by Jim Stewart on June 27th, 2003
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?
- Posted by Jonathan Kirwan on June 28th, 2003
On Fri, 27 Jun 2003 16:38:27 -0700, Jim Stewart
<jstewart@jkmicro.com> wrote:
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
- Posted by Mike Harrison on June 28th, 2003
On Fri, 27 Jun 2003 16:38:27 -0700, Jim Stewart <jstewart@jkmicro.com> wrote:
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.
- Posted by Joseph Goldburg on June 28th, 2003
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
"Jim Stewart" <jstewart@jkmicro.com> wrote in message
news:3EFCD573.2060805@jkmicro.com...
- Posted by Leon Heller on June 28th, 2003
"Jim Stewart" <jstewart@jkmicro.com> wrote in message
news:3EFCD573.2060805@jkmicro.com...
An MSP430 would be smaller, cheaper and take less power. Only 3.3 V, though.
Leon
--
Leon Heller, G1HSM
leon_heller@hotmail.com
http://www.geocities.com/leon_heller
- Posted by Jim Granville on June 29th, 2003
Jim Stewart wrote:
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
- Posted by Jim Stewart on June 30th, 2003
Thanks for all the $2 uart suggestions. I think that
I'll work on the MSP430 approach.
Leon Heller wrote:
- Posted by Mike Harrison on June 30th, 2003
On Mon, 30 Jun 2003 09:17:26 -0700, Jim Stewart <jstewart@jkmicro.com> wrote:
- Posted by Elroy the Seedy Impaler on July 31st, 2003
On Fri, 27 Jun 2003 16:38:27 -0700, Jim Stewart <jstewart@jkmicro.com>
wrote:
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
- Posted by Andrew Paule on July 31st, 2003
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:
- Posted by Jim Granville on July 31st, 2003
On Fri, 27 Jun 2003 16:38:27 -0700, Jim Stewart <jstewart@jkmicro.com>
wrote:
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
