Collected Comments on Home-Grown Daughterboard Design
"Bruce D. Lightner" <lightner-2huV/[email protected]>
| Newsgroups | gmane.linux.uclinux.actiontec |
|---|---|
| Message-ID | <[email protected]> |
Scott Christensen, > At the high baud rate this board talks may need to have RTS & CTS hooked > up to the UART. True. Howerver the "stock" Actiontec Daughterboard has no serial port "hardware flow control" hardware and/or firmware, so I left it off. Clearly there are unused RS-232 level-shifters in my schematic which could be used to add these signals in the future. > I came across the 16c552, which is a single IC containing dual 16c550's. > Is there a need for 2 serial ports? A good potential future addition I'm sure... > http://www.exar.com/products/st16c2552v42.pdf > > It appears there are a lot of people making clones of this device, with > all kinds of deviations on chip number in the name. "That's a fact Jack"...second sources are good! -------------------------------------------------------------------------- Chris Proctor, > I just had a look at the circuit diagram. > I noticed that you had inserted a resistor (R1) in the > USB5V line. I doubt this is necessary. > I was under the impression that there was already a resistor > in this line on the main motherboard. I also never saw one > in the photos of the actiontec daughter card. As some of say in the newly dubbed "information technology business": "Safety know no season". Therefore I added the resistor to make sure that the "nasty" +5V from the USB cable could not possibly damage the +3.3V only circuitry on the Actiontec PCB. We can always add one of those useful "zero ohm" resistors if the "extra" protection resistor turns out to be dedundant! -------------------------------------------------------------------------- Patrick McNamara, > I have crystals in hand. Well, actually their sitting in a bag on the > kitchen counter, but I picked up three today during a trip to Fry's. > I'll be working with the interface stuff tomorrow afternoon/evening. > Unfortunately, being a home owner means I have to do other stuff first. Great! Now, let's keep your priorities straight! Fun-stuff first, "home work" later! P.S.- You never told me why you wanted to add GPS to this? -------------------------------------------------------------------------- Best regards, Bruce -- Bruce D. Lightner Lightner Engineering La Jolla, California Voice: +1-858-551-4011 FAX: +1-858-551-0777 Email: lightner-2huV/[email protected] URL: http://www.lightner.net/lightner/bruce/ __ ActionHack Mailing List - ActionHack-W7/[email protected] http://www.express.org/mailman/listinfo/actionhack http://www.embeddedlinuxinterfacing.com/wiki.php/ActiontecDualModem