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KPR
04-07-2009, 01:05 AM
I am curious, looking at the schematics for theYBOX2 and the schematics for the standard nic layout , I noticed that the YBOX2 doesn't have a 25 MHz crystal, but uses pin 7 to generate a 25 mhz signal instead.. my question is is that good enough, wouldn't it be better to mod the board to include this, especially if one wanted to expand or re purpose the board in the future??

thx

k.

parts-man73
04-07-2009, 02:48 AM
crystals are cheap, I don't see a reason not to use it

a couple of reasons to use one -1 fewer pin needed to interface to the Propeller, and a little less code when using the onboard crystal, as without it, you need to feed a 25mhz frequency to it.

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Brian

uController.com (http://uController.com) - home of SpinStudio - the modular Development system for the Propeller

PropNIC (http://uController.com) - Add ethernet ability to your Propeller! PropJoy (http://uController.com) - Plug in a joystick and play some games!

SD card Adapter (http://uController.com) - mass storage for the masses Audio/Video adapter (http://uController.com) add composite video and sound to your Proto Board

KPR
04-07-2009, 03:11 AM
Hey Brian.. aren't you dev-ing a new prop board?

Mike Green
04-07-2009, 03:22 AM
On the other hand, crystals may be cheap, but they're not as cheap as a PCB trace and an otherwise unused I/O pin. If you've got the board space and the inclination, by all means, design in a 25MHz crystal, but there's nothing wrong with using a Prop cog counter to generate the 25MHz clock, particularly since it's a multiple of the existing 5MHz crystal (makes for low jitter using the PLLs).

parts-man73
04-07-2009, 06:01 AM
KPR said...
Hey Brian.. aren't you dev-ing a new prop board?


Well, since you asked, yes, I've got 3 new products that are waiting on me to document, then they will be released. I know one person (sorry OBC) that's chomping on the bit for me to release one.

2 of them are SpinStudio add-ons
Game Stacker plugs into all 4 ports of SpinStudio giving you all you need for playing games, You know, NES ports, mouse, keyboard, SD card, RCA jacks for video and sound
a MCP3208 ADC module that plugs into a single SpinStudio socket. Gives you 8 channels of 12 bit ADC with a sample rate of 100k samples per second. With a jumper you can select measurements of 0-3.3V or 0-5V

One is a stand-alone ADC and DAC lab with an on-board Prop. I just received the prototype boards today, and oh my! they are pretty!

Lots of new stuff coming!

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Brian

uController.com (http://uController.com) - home of SpinStudio - the modular Development system for the Propeller

PropNIC (http://uController.com) - Add ethernet ability to your Propeller! PropJoy (http://uController.com) - Plug in a joystick and play some games!

SD card Adapter (http://uController.com) - mass storage for the masses Audio/Video adapter (http://uController.com) add composite video and sound to your Proto Board