Let me add a small design confession on the 40 pin header also. I had hoped people would just be able to use IDE cables with it, that is actually why it is 40 pins. But what I didn't think of until after it was done was that IDE cables might be internally connected for the grounds, it turns out they are in the case of all of the ones I have so sadly you have to go buy a ribbon cable to get a board to board. I had hoped everyone would just have free ones laying around that would work but it was not meant to be...
When I make projects what I do is breadboard then I would make a daughter board PCB with a board to board ribbon cable for the final design. Or you can use jumper cables with 0.1" pitch. These come with some motherboards and SFE started to sell shorter blocks if you don't need a full patch of 40 to a daughter board.
Gotcha, there are a lot of parallel load DACs you probably could use easily enough if you just need raw level conversion. I was thinking of doing an audio player with LM3S9xxx and a big hunk of RAM (it has a RAM interface), it runs a bit faster at 80 MHz but still I don't know if that is fast enough to do the decode. That one has I2S on it for DAC.
Edit: the wav samples on the top google hit didn't work for this CODEC FWIW (files weren't there) RAW and competitors yes.
[quote author="phirephly"]There has been some work to try and get it running on higher-end AVRs and PICs, but the lack of floating-point support means we need significantly more fixed-point support to be able to perform the involved DSP calculations needed than is possible on 20MHz 8/16 bit processors.[/quote]
How much more power do you need? It is 1.25 DMIPS / MHz at 50 MHz, of course the core is integer only. I would think for such a low data rate codec (naively) you could do it with a lot of things. Are you planning to transducer the audio? PWM? Something else?
Right the RAM is the issue. The old style VGA has some RAMDAC that held the buffer and did the output from the buffer all in hardware. I just was looking at pixel clocks from SRAM it would be doable but $$$$ and power, SDRAM use or DDR requires more complexity.
If I had one of these boards, I'd be excited to port the Nuttx RTOS to it. I'm currently finishing a port for the TI Evalbot (LM3S9B92 based). TCP/IP (with DHCP, SMTP, TELNET, TFTP, HTTP) [/quote]
So you know there is no Ethernet MAC on this one unlike the LM3S9B92 which even has the PHY on it.
The reason it is male is so that you can use a ribbon cable and have a daughter board really. For breadboard I understand that is not ideal. The main advantage of using ribbon cables is that you preserve signal quality and speed.
I thought of doing two rows, on each side, but I wanted all SMD and so I couldn't. I could have left it unsoldered. Perhaps if there is a REV 3 I will do that if people don't mind soldering. There are some layout issues with doing it also... If you scrap the second JTAG interface you can get enough edge space.
[quote author="alextm"]I am planning on building a custom USB drive that handles at minimum the RSA side of the SSH protocol and preferably the whole process just sending and receiving packets to the host application which passes then directly to the network and sending and receiving text to the host application for interaction..[/quote]
Sounds like you are a good programmer. I have been interested in RSA like things on micros mostly because email transfer these days needs to be done over a secure layer. I find email a easy way to send command to internet enabled projects.
[quote author="schazamp"]I'm looking for a microcontroller environment that can function as a USB host. I'm building an MP3 player / media center for my car, and would like to be able to swap USB flash disks (containing, e.g., playlists, audio books, and music) depending on the trip I'm taking. .[/quote]
What will you use for the decode? A co-processor or do you think you can fit a codec into 32 K of RAM? I was thinking of using LM3S9B90 for a media player I made a post about it in another thread. It wouldn't be small for like iPodish things but it could work in a car too. I mostly looked into the CODEC overhead of FLAC though
LM3S9xxx series have ethernet, usb host and.... external memory interface so you can add a big hunk of SDRAM.
One project I keep thinking of working on is some simple VGA/DVI/HDMI output adapter for embedded systems.
The need for it is large. You can large LCD display for like 100 dollars but a tiny LCD often will cost you more. I bet lots of hackers have old smaller LCDs just laying around.
To make it cost effective it probably should use fast SDRAM or DDR with some FPGA or CPLD doing the logic for SPI. Basically I would have like some I/O pin set switch between what buffer to display and which to fill with data, plus a pin to say if it is command or data. You would need commands for switching refresh rates. I thought about trying this project with a pure microcontroller approach but the clock rate you need is rather high actually. There are some implementations out there that do low resolution for the hobby market but nothing high resolution.
Some chip out there might do it, after all digital cameras have HDMI on them now. I kind of think HDMI might be the way to go as it would open up all sorts of set top like devices that do all sorts of neat things for people in their home without a computer.
There has to be a way to get a co-op like business structure so that people can share the VIDs. Yes I am sure the USB might look down on it but if it is withing the law they shouldn't be able to do much.
I would attempt to structure it like a co-op with a one time open hardware developer fee, just some nominal amount. Have a website for the designs to be documented in a standard way sort of a souceforge for hardware.
I would use an ARM board of some sort for any sort of high though put SPI USB bridge. That could be mBed or Maple in theory. STM32 discover board would work and isn't much money. As would my Eridani board: http://teholabs.com I started a thread here about it also... It is kind of like Maple but without the IDE part but with better hardware.
If I had nothing I would get a STM32 discovery board. However given you don't sound like you are into bare bones hardware, that is a terrible choice as it is hard to write code for the peripheral library. (Or was when I used STM32F103).
I think which you choose boils down to what you are comfortable writing code for. The throughput on Eridani for USB MSC is about 750 kB/s as I recall. SPI ought to go at least 12 MBit if you do it carefully.
