Re: [tlug] Microcontrollers + linux: Digikey, ARM, NXP serial port

[jep200404 <jep200404@example.com>]

Mark Sadgrove wrote:

> I was wondering if anyone on the list had had some experience 
> purchasing microcontrollers in Tokyo and using them with Linux. 
> ... I'm interested in something like the parallax stamp ...

> I'd love to know
> (a) Good stores in Akihabara where you can buy them for cheap

Digikey is not a store in Akihabara or anywhere else, 
but I have been very happy buying from them for _decades_. 
Their web site is pretty straightforward. 

   http://dkc1.digikey.com/jp/digihome.html

They do not stock in Japan, so shipping might be expensive. 
Other folks in East Asia liked their service, but griped about 
the prices. When buying low quantities, price is not important 
to me. When buying small quantities, don't expect cheap prices. 

> (b) Any recommendations for cheap microcontrollers

The basic stamp is not a typical MCU and is not cheap. 

Regular MCUs are cheap in quantity. 8051 based MCUs are 
prolific and dirt cheap, but the whole architecture is awkward. 
Stay away from Microchip MCUs; they have the worst, 
most awkward architecture of any MCU I've ever seen. 
ARM MCUs are inexpensive, very powerful, and are friendly with 
open source tools. They are even supported by gcc[2]. 
The ARM architecture is very decent. 

> (c) Any tips r.e. programming controllers using a machine running linux

Choose a chip that is friendlier with Linux. 

The NXP (nee Philips) 8051 based and ARM MCUs are particularly 
friendly to program. Both can be programmed on the UART (RS-232) 
port, so they don't require any special programming hardware. 
Their 8051 based MCUs natively understand Intel Hex on the UART port. 
There are some toy-ish open-source 8051 compilers[1]. 
NXP's ARM MCUs don't grok Intel Hex, but one still programs 
them on the RS-232(UART) port, and there are multiple open 
source programs[3] to program them. I have used NXP's 
8051 and ARM MCUs successfully. Freescale (nee Motorola) makes 
decent MCUs. I've heard good things about Atmel but have not used 
them. I don't know what to think about Renasys (nee Hitachi) MCUs. 

ARM MCUs seems to be the friendliest MCUs to develop with 
open source. NXP MCUs seem to be particularly easy to burn 
over serial ports. 

[1] http://en.wikipedia.org/wiki/Small_Device_C_Compiler
[2] http://www.gnuarm.com/
[3] start here: http://pygmy.utoh.org/riscy/bootloader.html