Re: petSD project page

From: Nils Eilers <>
Date: Thu, 9 Jun 2011 03:04:20 +0200
Message-Id: <>
> Very tantalizing.
Nice to read this :-)

> I happen to have a couple of each of these lying about...
> They were designed with the ATmega644P in mind, so I'm curious how
> large the petSD code really is and if there are features which could
> be trimmed to keep it in 64K of code space.  

At the moment, it takes 52 KB and would fit into a 644p. RAM isn't a problem as well though you will have less buffers available.
But since there are still some features missing and there's not too much free space, I don't recommend the 644p for this design.
If you used a socket for the 644p (I guess you did), you can replace the 644p at any time later by a pin compatible 1284p so there's no problem at all.

> I'm not suggesting "don't make a dedicated petSD board", but I
> am curious if it would be worth attempting to make a small riser board
> with the SN75160/75161 on it

Go for it! :-)
I'll build the firmware if you've done your hardware. Takes about one hour only.
Do you think, you can create the schematic by yourself or should I made one for you?

> and possibly adding support to the code to use a DS1307

I already read a datasheet of this nice RTC back then but I couldn't use it in the early AVR at 3.3V days... ;-/
But now the AVR runs at 5V, so I'll get some and add support for them. It needs less external parts, that's great.

> to use the Makerbot Motherboard as a development platform for the petSD
> firmware.

Do you have a JTAG interface?
Is there a serial interface for reading debug output? I didn't see a RS-232 voltage converter or serial-USB-adapter on that board.

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Received on 2011-06-09 02:00:12

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