# LPC Serial Boot Loader **URL:** \ **Category:** MicroMod\ **Tags:** arm-lpc\ **Created:** [May 23, 2007, 8:53am UTC](https://community.sparkfun.com/t/lpc-serial-boot-loader/4465 "2007-05-23T08:53:17Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![dekutree64](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@dekutree64](https://community.sparkfun.com/u/dekutree64)\ **Post date:** [May 23, 2007, 8:53am UTC](https://community.sparkfun.com/t/lpc-serial-boot-loader/4465/1 "2007-05-23T08:53:17Z")
[http://www.sparkfun.com/commerce/produc … cts\_id=714](http://www.sparkfun.com/commerce/product_info.php?products_id=714) Has anyone here successfully used this to program the LPC2138 or similar? I’m trying to decide between it and the [[UsbScarab](http://www.sparkfun.com/commerce/product_info.php?products_id=8307). Obviously the scarab would be nice for debugging, but I like making very small robots and a 6-pin connector would take up a lot less space than a 20-pin JTAG.]([http://www.sparkfun.com/commerce/product\_info.php?products\_id=8307](http://www.sparkfun.com/commerce/product_info.php?products_id=8307)) ---
**Author:** ![dshuman](https://avatars.discourse-cdn.com/v4/letter/d/85f322/32.png) [@dshuman](https://community.sparkfun.com/u/dshuman)\ **Post date:** [May 23, 2007, 9:32am UTC](https://community.sparkfun.com/t/lpc-serial-boot-loader/4465/2 "2007-05-23T09:32:26Z")
> dekutree64: > [http://www.sparkfun.com/commerce/produc … cts\_id=714](http://www.sparkfun.com/commerce/product_info.php?products_id=714) > > Has anyone here successfully used this to program the LPC2138 or similar? I’m trying to decide between it and the [[UsbScarab](http://www.sparkfun.com/commerce/product_info.php?products_id=8307). > > Obviously the scarab would be nice for debugging, but I like making very small robots and a 6-pin connector would take up a lot less space than a 20-pin JTAG.[/quote] > > There is another option that will give you all the advantages of JTAG with a minimal pin count. The standard ARM defined connector is a 2x10 set of header pins, but it is possible to implement JTAG debugging with just 7 pins, using an adaptor from the 20 pin ARM standard. That method is used in some cell phones that just have the pads to the JTAG interface exposed though an opening in the battery compartment. For JTAG the necessary pins are: > > VCC > > GND > > TDI > > TDO > > TMS > > TCK > > nSRST > > nTRST _can_ be omitted, if necessary. > > [http://www.arm.com/support/faqdev/4182.html](http://www.arm.com/support/faqdev/4182.html) > > Since you are using an LPC2138, nTRST will be activated internally any time that you activate nSRST anyway. > > Obviously, more GND signals do help with signal integrity. > > –Dave]([http://www.sparkfun.com/commerce/product\_info.php?products\_id=8307](http://www.sparkfun.com/commerce/product_info.php?products_id=8307)) ---
**Author:** ![AMONTEC](https://avatars.discourse-cdn.com/v4/letter/a/898d66/32.png) [@AMONTEC](https://community.sparkfun.com/u/AMONTEC)\ **Post date:** [May 23, 2007, 8:35pm UTC](https://community.sparkfun.com/t/lpc-serial-boot-loader/4465/3 "2007-05-23T20:35:09Z")
Start with Amontec JTAGkey-Tiny. There are no ARM Debugger solution smaller and cheaper. Only €29.- from [http://www.amontec.com/jtagkey-tiny.shtml](http://www.amontec.com/jtagkey-tiny.shtml). Laurent ---
**Author:** ![AMONTEC](https://avatars.discourse-cdn.com/v4/letter/a/898d66/32.png) [@AMONTEC](https://community.sparkfun.com/u/AMONTEC)\ **Post date:** [May 23, 2007, 8:37pm UTC](https://community.sparkfun.com/t/lpc-serial-boot-loader/4465/4 "2007-05-23T20:37:48Z")
[http://www.amontec.com/jtagkey-tiny.shtml](http://www.amontec.com/jtagkey-tiny.shtml) ---
**Author:** ![dekutree64](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@dekutree64](https://community.sparkfun.com/u/dekutree64)\ **Post date:** [May 24, 2007, 7:34am UTC](https://community.sparkfun.com/t/lpc-serial-boot-loader/4465/5 "2007-05-24T07:34:53Z")
Thanks guys! I think I’ll go with the amontec programmer using the 7 pin interface. ---
**Author:** ![bertrik](https://avatars.discourse-cdn.com/v4/letter/b/53a042/32.png) [@bertrik](https://community.sparkfun.com/u/bertrik)\ **Post date:** [May 24, 2007, 6:31pm UTC](https://community.sparkfun.com/t/lpc-serial-boot-loader/4465/6 "2007-05-24T18:31:04Z")
The JTAGkey-tiny looks very tempting indeed, but the shipping cost is really high (22.80 euro shipping to get a 29 euro item)!