While working on my next book, I've built a small general-purpose prototyping board. This PCB is also intended to be useful for those projects where someone says "please prototype this" and it requires a micro that's only available in SMD.
Here are the schematic and component placement:
The board is 5.1"x3.0", 0.062" FR4 with immersion tin (RoHS) finish, 2- sided solder mask and component-side silkscreen. FR4 is *not* guaranteed to survive Pb-free reflow profiles, and this board is not checked against manufacturability design rules; it is strictly intended for hand assembly only. Because of this, I have modified a couple of the footprints to make hand-soldering easier (I'm thinking particularly of the leadless accelerometer footprint).
The board includes footprints and interface circuitry for an SD/MMC card slot in SPI mode, two Motorola pressure transducers, an ADXL322
2D accelerometer, an AVR ATmega48,mega88,mega168,mega8 or mega16 OR ATmega32/64/128 chip (in TQFP), and either one or two MSP430F2013s (in TSSOP; would also support other 20xx series parts since they have basically the same pinout). Can be configured for a global Vcc=5V or 3V, has two RS232-level 3-wire serial ports, and offboard .100" connections for all uncommitted I/O (as well as most of the onboard signals). The AVR block has connections for ISP, debugWire and JTAG; the MSP430s each have independent SBW debug connectors and watch xtals. There is also a small, isolated area for a quad op-amp package in SOIC, with appropriate component spaces and wiring around it to configure each quarter as an inverting or non-inverting op-amp, with an optional cap across the feedback resistor. The main reason I will be using this space is impedance matching for external transducers to the ADC channels.Is anyone else interested in this board? I am planning to order 100 for myself, and if there is interest from others I will probably order
1K. I would likely be able to sell them for about $6.50 including [U.S.] shipping.Any suggestions on what you think is missing?