Micro choice with 4 UARTs

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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


Re: Micro choice with 4 UARTs

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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.


Re: Micro choice with 4 UARTs
On 29 Jul, in article

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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          | snipped-for-privacy@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/ PC Services
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Re: Micro choice with 4 UARTs

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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.



Re: Micro choice with 4 UARTs

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

Ian

Re: Micro choice with 4 UARTs

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




Re: Micro choice with 4 UARTs

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Maxim has a SPI uart

Kasper



Re: Micro choice with 4 UARTs

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A slave PIC/AVR is probably cheaper though



Re: Micro choice with 4 UARTs

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

Kasper



Re: Micro choice with 4 UARTs

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

http://www.embeddedrelated.com/usenet/embedded/show/30013-1.php
        
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www.EmbeddedRelated.com

Re: Micro choice with 4 UARTs
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

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Re: Micro choice with 4 UARTs
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  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


Re: Micro choice with 4 UARTs



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You Might get that many with a Cypress PSoC



Re: Micro choice with 4 UARTs
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Cypress PSoC CY8C29466 is around 5 USD in small quantities and it can
provide 4 UARTs.

Re: Micro choice with 4 UARTs
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The forthcoming ATmega640 is rumoured to have the same peripherals
and should be pin compatible and cheaper (when available)

--
A. P. Richelieu



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