Lpc2000

Robert Adsett wrote:

>At 10:52 AM 12/17/05 -0500, Tom Walsh wrote:
>  
>
>>Well, you could read the Philips manual for the LPC213x family..  Or,
>>you could get an modestly priced evaluation board to try out.   Both
>>ways, you will find that you "could" discard JTAG and use those pins for
>>I/O.  Realistically, I don't think that you would want to consider doing
>>that as how would you develop code???
>>    
>>
>
>Wimp :)
>
>It is, of course, quite feasible to develop without using a JTAG.  Indeed 
>on some micros with little or nor ICE or on chip debug support it's necessary.
>
>There's a lot to be said for observing the behaviour of the device in 
>question and determining from that what must be happening internally.  Add 
>a few pins to toggle to indicate code paths and timings and a serial I/O 
>port for data dumps and you cover a lot of ground, some of which cannot be 
>covered very effectively with JTAG.
>
>  
>
Been there and done that, no thank you!  ;-)   I've been supporting a 
product for the past 12 years which was 8051 based and I did all my 
debug from an EPROM emulater, single LED, and secondary serial port.   
Eventually I figure out how to put a 4bit LCD on for the really tough 
problems.

I've had experience with debugging 80188 from a pod (ICE), that was 
better, but the freakin' POD would be difficult to get working 
sometimes: bad connections, bad Windows driver, sick Windows install, [...].

This project, I chose a processor with built in debug capabilities 
(JTAG) and spent some real money and get an Abatron BDI2000 pod.  Then 
spent time learning about Insight.  GNU gdb I'm familiar with as I've 
run Linux for many years.

I won't part with my JTAG!  I just love how it works, it so reliable and 
stable.  I've chained the JTAG lines of the two processors together and 
can debug them both with a single pod and two instances of Insight.  No 
thank you, I'll keep my JTAG!  It's too painfull to do it the "other 
way"!  :-)


>Of course there are situations where JTAG or a real ICE is very nearly 
>essential.  In fact I'm not yet convinced that JTAG is a complete 
>replacement for a proper ICE since I have yet to run into a situation on a 
>JTAG equipped micro that demanded the full capabilities of an ICE.
>
>Serial downloads do work quite well and since JTAG takes up so many general 
>purpose I/O pins I can see why someone would want to dispense with it, 
>especially on the lower pin count devices.  A lot of products really don't 
>have room for a 144 pin package especially just to add a debugging interface.
>
>  
>
When I needed more I/O on the LPC2138 / LPC2106 board, I looked to the 
SPI bus.  There are three MAX3100 UARTs  and a NLSF595 LED driver on 
SPI0 of the LPC2106 processor.  SPI works really well.

The only thing I do wish for is an offering from Philips for a 48 / 64 
pin LPC2000 package with something like 32K of Flash and 256K of SRAM.   
I've some ideas of what I could do with that: Add an SD card to the SPI, 
then load programs into the SRAM to run them from there...

I do like the self-contained aspect of the LPC2000 parts, that is their 
best feature. 

Regards,

TomW

-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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