Hello all,

I am looking for a low cost micro with 4 UARTS. The requirments are
quite staringhtforward since none of the ports will be going that
quickly (4800 baud to 19200 baud) and only a few hundred bytes per
second on 3 of the 4 ports (with the last port mostly idle).

I'll also need some simple I/O (about 6 I/O lines should be OK) plus an
I2C or similar (but that could be bit-banged since there won't be much
data to pass on this bus).

Ideally I'd like FLASH and RAM on chip.

The target volume for this product would be a few thousand per year.

I know of rabbit and it looks like the latest ATMega2560 would be OK
but are there any others?

Thanks

Iain

tebbutt@hotmail.com wrote:
I suggest you take a look at the Renesas H8 series. The documentation
is quite good, and a free C/C++ compiler (gcc) is available. While the
H8 series might not qualify for "low cost", it definitely has features
enough.

On 29 Jul 2005 07:05:47 -0700, tebbutt@hotmail.com wrote:

At that baudrate you could easily do it in software without too much trouble.
If there are other timing constraints that preclude this, maybe use a cheap slave PIC/AVR as an
intelligent UART peripheral.
Either route is likely to be cheaper & more flexible than constraining yourself to the few parts
with enough hardware uarts.

<tebbutt@hotmail.com> wrote in message
news:1122645947.857251.167240@g14g2000cwa.googlegr oups.com...
Maxim has a SPI uart

Kasper

You may find some relevant comments in this thread about micros with
UARTs:

http://www.embeddedrelated.com/usene...ow/30013-1.php

This message was sent using the comp.arch.embedded web interface o
www.EmbeddedRelated.com

Mike Harrison wrote:

And one piece of bit bang code could run all serial ports running at the
same baud rate.

Ian

Hi Iain,

software implementation of some of the UARTs is a given for a low cost
device, one with 4 HW UARTs is much more expensive than one with 1 UART
and 3 in SW. You mentioned a few hundred bytes a second, well that
would be continous operation if using 4800 Baud, gives you max 480
bytes/sec.

What is different about the one UART? Guess you want to have that one
in HW.
There are some really nice LPC915/LPC916/LPC917 devices from Philips.
They run from an internal oscillator (7.373 MHz) and all have a HW UART
and 2 also have an I2C in hardware.

more information can be found here:
http://www.standardics.philips.com/products/lpc900/all/

They come in 14/16-pin packages with 2k Flash and 256 bytes RAM. As the
core is a 2 clock per instruction cycle, it is about as fast as 4 MHz
AVR or a 14.7 MHz PIC or for that matter an old 8051 running at 44 MHz.


An Schwob

tebbutt@hotmail.com wrote:

On 29 Jul, in article
<1122647442.681181.177510@g43g2000cwa.googlegroups .com>
hans_odeberg@yahoo.com "Hans" wrote:

Well the one that immediately springs to mind is the H8S/2378

5 hardware UARTS (capable of much higher speeds than 19200)
Each with their own interupt vectors
512KB Flash
32K SRAM
Lots of other I/O from SDRAM/DRAM controllers DMA IRdA I2C
Lots of timers

Internal memory is on 16bit wide bus

Various compilers support them I am biased towards GNU for them.

--
Paul Carpenter | paul@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/> PC Services
<http://www.gnuh8.org.uk/> GNU H8 & mailing list info
<http://www.badweb.org.uk/> For those web sites you hate

On Fri, 29 Jul 2005 17:03:41 +0000, Ian Bell <ruffrecords@yahoo.com> wrote:

...or even different baudrates with a timer interrupt running at twice the highest rate, but this
gets a little more interesting...

On Fri, 29 Jul 2005 17:03:07 +0200, "Repzak" <repzak@GEDhotmail.com> wrote:

A slave PIC/AVR is probably cheaper though

tebbutt@hotmail.com wrote:
What else does it have to do ?
The spec is simple, but the devices you've metioned are large,
so there is probably something else missing.
For the tasks above, you could choose a faster, small uC, like
the C8051F330, or the new AT89LP2052/4052.
These are 25/20 MIPS, and have the 80C51 core that handles
bit-level uarts very well. The LP2052 also has a double buffered
SPI, so can slave properly to other uC.
When doing bit-level Serial, you have tight time constraints, so
it is best to focus on that, in a smaller controller.

-jg

tebbutt@hotmail.com wrote:

You Might get that many with a Cypress PSoC

tebbutt@hotmail.com wrote:
Cypress PSoC CY8C29466 is around 5 USD in small quantities and it can
provide 4 UARTs.

But in a production line the programming part can be expensive in time

Kasper

The forthcoming ATmega640 is rumoured to have the same peripherals
and should be pin compatible and cheaper (when available)

--
A. P. Richelieu