Re: A wifi chip with serial i/o pins?

[David Schmenk <dschmenk@gmail.com>]

On Saturday, January 12, 2013 10:13:34 PM UTC-8, Kevin wrote:
> On Saturday, January 12, 2013 11:29:47 PM UTC-6, BLuRry wrote:
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> > Just read about this: http://www.ti.com/product/cc3000
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> > It would be pretty awesome if the serial pins on this chip were capable of relaying port input/output.  I mean, wouldn't it be awesome to have a small wifi box at the end of a serial cable?  I'm not sure what the extent of the RS232 "test" mode provides, but it's possible that this might be worth exploring, eh?  It's not like Uthernet cards are rolling off the line again any time soon...
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> > -B
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> there are a number of network solutions "on a chip" but they sort of fall into two camps
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> camp 1 is a interface chip that takes care of all the physical layers and leaves your machine to deal with the tcpip stack and all that fun
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> camp 2 like the wiznet series does pretty much every thing for you and appears to the host as serial device. sure you can load a terminal emulator and browse wikipedia in text mode. even setup a simple web server. More advanced things like ADT or AGS I dunno... do they support a PPP style connection?
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> wiznets are not cheap as far as components go (in the land of fraction of a cent parts, nearly 30 bucks for an IC is expensive, but cheap in the grand scheme of things)

Just for clarification, this chip, and the Wiznet chips, both interface to the host through a serial interface known as SPI, a common embedded device bus (http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus).  It is still a register interface to the host software, but at a much higher level than the older chips, like in the Uthernet.  The Wiznet and this TI chip present an IPV4 socket level interface to the host, with the access to lower level protocols.  In order to interface to a serial port on the Apple II would take another layer to convert the SPI protocol to RS232.  You can get the Wiznet chip from JameCo for something like $5 and this TI chip looks like $10.  Still not cheap, but given the functionality they provide can reduce the cost of the design in other places.

In order to interface the SPI bus directly to the Apple II, one could (if they were so inclined), fake the SPI protocol with a 6522, an extra shift register, and a little code :-)

Dave...