Lpc2000

varuzhandanielyan wrote:

>I am asking mainly just about LPC213x and LPC214x series.
>Realy they have too few pins for such a powerful processor.
>So each pin is a very valuable resource and it is pity to
>lost it only for debug purposes.
>By the way I would be happy to see a 100-pin version of this
>series with more IO pins, especially with PWM not shared with interfaces.
>Anyway, I am still waiting for discussion about P1.24-P1.31
>pins usage.
>
>  
>
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???

Although, you could use those pins for simple, less critical functions 
like: blinkings LEDs, or something like that.  Why not, instead, be 
looking into I2C port expanders, or SPI devices, to get more I/O ?  
--OR-- Maybe look at other ARM processors from Samsung, Hitachi, 
Motorola, Cirrus Logic, SGS-Thompson, ..... ?

Use the right tool for the right job.. (or chip ;))

Regards,

TomW


>Varuzhan 
>
>--- In lpc2000@yahoogroups.com, "seangra" <embeddedrelated@w...> wrote:
>  
>
>>What about for the LPC213x and LPC214x series?  I think they only 
>>have 1 JTAG port, right?
>>
>>--- In lpc2000@yahoogroups.com, Tom Walsh <tom@o...> wrote:
>>    
>>
>>>varuzhandanielyan wrote:
>>>
>>>      
>>>
>>>>Maybe very silly question, but...
>>>>Can I use P1.24-P1.31 pins in my design as
>>>>IO, if I plan to debug the soft using JTAG,
>>>>particularly ULINK.
>>>>Technical data references, experience, opinions?
>>>>
>>>> 
>>>>
>>>>        
>>>>
>>>I do.  The LPC2106 has a secondary JTAG port, you just need to 
>>>      
>>>
>>turn it 
>>    
>>
>>>on..   You must download the first Flash image without JTAG, but 
>>>      
>>>
>>after 
>>    
>>
>>>that it works fine: flash new program, debug, etc.
>>>
>>>This is the code sequence in the first few bytes of my crt0.S:
>>>
>>>================ begin ====================
>>>_start:
>>>start:
>>>_mainCRTStartup:
>>>
>>>// Initialize Interrupt System
>>>// - Set stack location for each mode
>>>// - Leave in System Mode with Interrupts Disabled
>>>// -----------------------------------------------
>>>;
>>>      ldr   r0, JTAG2
>>>      ldr   r1, PINSELREG
>>>      str   r0, [r1]       // activate secondary JTAG port.
>>>;
>>>      mov   r3, #65536
>>>startdelay:
>>>      subs  r3, r3, #1
>>>      bne   startdelay     // give debugger time to catch us.
>>>;
>>>
>>>=============== snip ======================
>>>
>>>With JTAG2 & PINSELREG as:
>>>
>>>================= begin ===================
>>>JTAG2:
>>>   .word 0x55400000
>>>PINSELREG:
>>>   .word 0xe002c004
>>>================== snip ===================
>>>
>>>
>>>The short delay loop lets the JTAG unit "catch up" and stop the 
>>>processor early in the boot process.  Otherwise, I've run into 
>>>      
>>>
>>problems 
>>    
>>
>>>where the processor will run into a brick wall (bad code) before 
>>>      
>>>
>>the 
>>    
>>
>>>JTAG can catch it out of reset.
>>>
>>>
>>>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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-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
----------------------------------------------------