Revision as of 15:59, 2 November 2008

Processor discussion

A

• • Please use the ARM processor (32bit address space) - it has no Bank switching; ARM has a big linear directly addressable memory. Can get flashed by this open source tool: lpc21isp, yahoo download (after user registration).
    • Look e.g. on the cheap LPC214x (LPC2144-LPC2148 has 14 ADC multiplexed channels - two internal ADCs). Chip price: digikey.com: LPC2144 US$ 8.4, LPC2148 US$ 11.2. The ARM architecture is "old" (from 1983), wildly known, used, efficient(high mips/watt) and uses low power (different kind of deep sleep).
    • Test/development/production boards:
      • USB powered through USB-flash port, only mentions 2 ADC-ports: embeddedartists.com: LPC2148 Education Board (two USB ports - one for programming via a ftdi-chip(USB<->serial) - and one directly connected to LPC2148)
      • ARM MP3/AAC Player Quote: "...This is my MP3/AAC player project. The difference to most other players is that decoding is not done on a specialized IC (like VS1001), but directly on the microcontroller. It can play MP3 (all bit rates) and AAC (up to ~256 kbps) from SD card in real time. The project is work in progress..."
      • LPC2148-based Line-tracing Race Car Robot Kit
      • ARM7 LPC2148 mini board, ARM7-Base development board for LPC2148
      • ARM1136JF-S-based: buglabs.net, Some applications, bugcommunity wiki
      • Gumstix
      • AT91SAM7S256 (ARM) based: Lego Mindstorms NXT, NXT Programming Software
      • Alekto; DIN RAIL mountable
      • Atmel AT91SAM7X256 based (also ARM): Controller Board Overview, makingthings.com, sourceforge.net: makingthings
    • Open source support:
      • LPC214x USB stack
    • Links:
      • NXP: LPC2141/42/44/46/48 - Single-chip 16-bit/32-bit microcontrollers
      • ARM7 NXP (formerly a division of Philips) LPC Microcontroller
      • Building Bare-Metal ARM Systems with GNU: Part 1 - Getting Started
      • ARM-Projects
      • Embedded USB - a brief tutorial
      • ALDS

Users:hns

This is what has been thought of: a simple processor that still suppports A/D converters and USB. A good candidate appears to be http://ww1.microchip.com/downloads/en/DeviceDoc/41124c.pdf Kost approx. 5 USD.

Using an ARM processor just to convert some samples per second into USB appears to be overkill to me. But it is just one of the options to considered. A drawback appears that the ADC resolution is just 8 bit. This is quite coarse for some sensors. 12 bit wouldbe better.