Forums

Interest in AVR+MSP430 "general purpose" proto board?

Started by larwe April 15, 2007
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:

<http://www.larwe.com/temp/526-prelim-schematic.gif>
<http://www.larwe.com/temp/526-prelim-layout.gif>

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?

On Apr 15, 7:50 pm, "larwe" <zwsdot...@gmail.com> wrote:
> 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: > > <http://www.larwe.com/temp/526-prelim-schematic.gif> > <http://www.larwe.com/temp/526-prelim-layout.gif> > > 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).
Yes, make it PLC8 compatible. We plan on making a cheaper version without internal A2D (< $2), those with ratiometric compensations are too expensive (> $5). Ours will be ADXL278 pin compatible. We are also looking for PLC8 socket for it. Have you seen any, since you must be working on something similar?
> > 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;
We don't really want the MSP, unless you can program it from the AVR. We would prefer an ARM instead, and be programmable from the AVR. One programmable micro is enough. We want: AT90USB82 (Atmel) + LM3S828 (Lmi) + PCF8576D (Nxp)
> 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?
On Apr 16, 11:39 am, "linnix" <m...@linnix.info-for.us> wrote:


> Yes, make it PLC8 compatible. We plan on making a cheaper version > without internal A2D (< $2), those with ratiometric compensations
PLC8? Never heard of it, and Google gives no result.
> We would prefer an ARM instead, and be programmable from the AVR. > One programmable micro is enough. We want:
That is, however, a different product. I was looking more for suggestions like "I could really use this board if you added an RS485 transceiver" or that ilk.
On Apr 16, 11:43 am, "larwe" <zwsdot...@gmail.com> wrote:
> On Apr 16, 11:39 am, "linnix" <m...@linnix.info-for.us> wrote: > > > Yes, make it PLC8 compatible. We plan on making a cheaper version > > without internal A2D (< $2), those with ratiometric compensations > > PLC8? Never heard of it, and Google gives no result.
May be PLCC 8. Three pins on the long sides and 1 on the short side. Used by several Analog Devices and Memsic Chips. A custom socket might be possible.
> > > We would prefer an ARM instead, and be programmable from the AVR. > > One programmable micro is enough. We want: > > That is, however, a different product. I was looking more for > suggestions like "I could really use this board if you added an RS485 > transceiver" or that ilk.
larwe wrote:
> 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.
<snip>
> 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?
Since you asked, why not add a C8051F41x footprint, and cover all the bases ? That gives you 12 bit ADC, 12 bit DAC, 5V Vcc, and 50MHz speed, and access to (very) low cost ICE tools. -jg
> Since you asked, why not add a C8051F41x footprint, and cover > all the bases ?
Do you have a specific device in mind? I could shuffle stuff around and make room without too much trouble.
I like the MSP, but the 2013 is a pretty weak variant. And everyone
already has one of those MSP USB dongle devices.

I concur with the other poster that Arms are great, but that goes
against the theme here. I think 8 and 16 bit processors are the focus
here.

LM324 Op-amps are bit dated by today's standards.

I'd go with a low-dropout regulator.

It's a pet peeve of mine to have SD slots if there's no SD filesystem
software. Of the hundreds of DEV boards that have a slot, only a
couple have open software to utilize the slot. I'm not sure if the AVR
world has this kind of open software?

I'd probably throw in an RTC and Termperature chip, both preferably
I2C.


larwe wrote:
>>Since you asked, why not add a C8051F41x footprint, and cover >>all the bases ? > > > Do you have a specific device in mind? I could shuffle stuff around > and make room without too much trouble.
C8051F410-GQ is the LQFP32 32KF C8051F412-GQ is the LQFP32 16KF These are normally ex stock at Digikey / Mouser. -jg
On Apr 16, 6:26 pm, "Eric" <englere_...@yahoo.com> wrote:
> I like the MSP, but the 2013 is a pretty weak variant. And everyone > already has one of those MSP USB dongle devices.
Bear in mind that this board is (a) for building little customer projects that I can't do on .100" perfboard, and (b) for my fourth book, which is about the MSP430, inter alia. The ez430 is great, but the target board in there has no footprints for, say, accelerometers.
> I concur with the other poster that Arms are great, but that goes > against the theme here. I think 8 and 16 bit processors are the focus > here.
Really, I put the MSP430 in the same general performance category as the high end of 8 bits.
> LM324 Op-amps are bit dated by today's standards.
True, but the pinout is used by a lot of other quad op-amps. In fact, I think the majority of quad op-amps in SOIC14 are pin-compatible.
> I'd go with a low-dropout regulator.
Noted... however you probably also observed that a lot of the components have no values. This is because they are TBD and application-dependent. There are low-dropout versions of the LM317 in the same SOT223 package, which the user is free to substitute according to the application needs.
> It's a pet peeve of mine to have SD slots if there's no SD filesystem > software. Of the hundreds of DEV boards that have a slot, only a > couple have open software to utilize the slot. I'm not sure if the AVR > world has this kind of open software?
I can feel utterly insulated against this peeve, since I have published a public domain FAT12/16/32 filesystem and have tested it on AVR and MSP430, among other platforms ;) <http://www.zws.com/products/dosfs/index.html> (Please note, there are a few bugs in the current version up there. I'm working on updating the site).
> I'd probably throw in an RTC and Termperature chip, both preferably > I2C.
Hmm, I'll look at that. Thanks for the feedback. In my application, the temp sensors need to be attached to various mechanical hardware - so they are wired to the I2C bus on flying leads.
On Apr 16, 7:24 pm, Jim Granville <no.s...@designtools.maps.co.nz>
wrote:
> larwe wrote:
> > Do you have a specific device in mind? I could shuffle stuff around > > and make room without too much trouble. > > C8051F410-GQ is the LQFP32 32KF > C8051F412-GQ is the LQFP32 16KF > > These are normally ex stock at Digikey / Mouser.
Okay. I'll look at the eval board configuration and see if it will fit.