BASIC Stamps run at 3.3V? BS2px 3.3V
Can you folks let me know if it's possible, and/or what problems I'd run into in modifying a BASIC Stamp to run at 3.3V?
Specifically, I'm using a BS2px for the speed, but would like to modify it to run at 3.3V· -- and >32MHz, but that's the second question.
Can I simply change out the on-board LT1121-5v regulator for an LT1121-3.3v and·use an SX-Key or Blitz·on a tacked-in sky-wire connection to reprogram the FUSEX register reset threshold·BOR1: BOR0 bits to 2.6V or 2.2V?· (or reprogram, THEN change the regulator!).· And rather than change the regulator, can I just leave Vin open and feed 3.3V in on the Vdd pin?
Would that lead to failing of the BS2 program loading over RS232 port feature when running at 3.3V?
Second question, for·more speed, can I simply change out the 32MHz resonator for a 40 or 50MHz resonator?· I realize that would throw off timing of some BS2 commands, but is there any critical timing that could not be readjusted for in the use of those commands?· IE, could I not use the serial program load feature?
I welcome your thoughts and advice,
-- BrooksL
BTW, why does Parallax not seem to have any intermediate performance product between the BS2px and the Propeller?· ...seems like BSxx line additions could be made around a PIC with on-board RAM (or SX + SPI RAM if·need be·to), a few hardware peripherals, and·3.3V~5V operation options...
·
Specifically, I'm using a BS2px for the speed, but would like to modify it to run at 3.3V· -- and >32MHz, but that's the second question.
Can I simply change out the on-board LT1121-5v regulator for an LT1121-3.3v and·use an SX-Key or Blitz·on a tacked-in sky-wire connection to reprogram the FUSEX register reset threshold·BOR1: BOR0 bits to 2.6V or 2.2V?· (or reprogram, THEN change the regulator!).· And rather than change the regulator, can I just leave Vin open and feed 3.3V in on the Vdd pin?
Would that lead to failing of the BS2 program loading over RS232 port feature when running at 3.3V?
Second question, for·more speed, can I simply change out the 32MHz resonator for a 40 or 50MHz resonator?· I realize that would throw off timing of some BS2 commands, but is there any critical timing that could not be readjusted for in the use of those commands?· IE, could I not use the serial program load feature?
I welcome your thoughts and advice,
-- BrooksL
BTW, why does Parallax not seem to have any intermediate performance product between the BS2px and the Propeller?· ...seems like BSxx line additions could be made around a PIC with on-board RAM (or SX + SPI RAM if·need be·to), a few hardware peripherals, and·3.3V~5V operation options...
·
Comments
regards peter
The SpinStamp is the Propeller chip. I don't mind over-kill processing capabilities at a lower cost, but different language and development environment... not so good.
The 3.3V request is to decrease power requirements of the entire design BS2px, peripheral devices and all, with minimal code porting issues.
The higher speed request is to increase performance to afford windows of sleep-time in the application's code.
The BS2 wont run at 3.3v because of the reset supervisor chip on board, But the BS2SX might. I think if it did it would be pretty close to the edge of browning out.
I take it Your looking at a battery powered App.?
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The Truth is out there············___$WMc%___···························· BoogerWoods, FL. USA
On the BS2px, the brown-out detector (brown-out is really a misnomer because brown-outs are supposed to be distiguishable from power-outs) is in the SX48BD device and it's threshold is programmed by two bits in the FUSEX register.
Yep, it's a battery powered app and I'm hoping to find someone who can affirm this track will probably work rather than be a dead end.
Ooh, can I reprogram just the FUSEX register, or do I need the Parallax BS2px source for the SX48BD??
-- BrooksL
Since the SX48-based Stamps have their security bits set, I doubt you'd be able to reprogram the BOE without also erasing the PBASIC interpreter. IIRC, there are also some issues with the EEPROM timing that need to be addressed at the lower voltage.
-Phil
However, the above does not apply to the BS2px module. It still uses the SX48's internal BOR42 setting, and there is nothing you can do about that.
BrooksL said, "The higher speed request is to increase performance to afford windows of sleep-time in the application's code." Another consideration is the device reset timer setting in the FUSEX register of the SX48. All the Stamps _except_ the BS2pe use the DRT=11 setting, which gives an 18 millisecond delay on wake up from SLEEP. The BS2pe uses DRT=10, which makes the delay almost 2 orders of magnitude less, 0.25 millisecond. The consequence is that the BS2pe can wake up from SLEEP, do useful status checks, and go back to SLEEP during the time the other Stamps would still be lying in bed doing nothing but at full power. That makes the 'pe more able when it comes to short sleep-wake cycles.
The MOBO Stamp and also my OWL2pe data loggers are based on the BS2pe with 2.6 Volt BOR setting (which allows operation to -40 degC), and also the 0.25 ms DRT setting for more efficient sleep/wake cycles.
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Tracy Allen
www.emesystems.com
Thanks, this is getting good now! I ran into your OWL web page a few months ago. I need to stay in the 24pin form-factor; so, the MoBoStamp-pe is out.
I looked at the 24FC128 EEPROM and don't see the problem you suggest; it appears the 24FC can still hit the 1MHz clock rates as long as it's VCC >2.5V.
Thanks for the mention of the DRT bits; I saw those but hadn't made the connection between those and the sleep wakeup delay.
So, it sounds like a 3.3V BS2px mod is doable except for the security bits set in the SX48BD. Do you think Parallax would trust enough to provide the existing .HEX file for modification?? [noparse]:)[/noparse]
-- BrooksL
The EEPROM issue has to do with setup times, not with clock speed per se. My guess is that it would not be a problem at 3.3. It is your hack though, and you are on your own!
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Tracy Allen
www.emesystems.com
So, what would really be nice is a BS2px-e product - that runs 3.0~5.5V Vdd, 32~40MHz, DRT=10, with on-board 64Kb 1MHz SPI RAM and native PBASIC instructions to access the RAM. That should be an easy turn to production....
-- BrooksL
"So, what would really be nice is a BS2px-e product - that runs 3.0~5.5V Vdd, 32~40MHz, DRT=10, with on-board 64Kb 1MHz SPI RAM and native PBASIC instructions to access the RAM. That should be an easy turn to production...."
It's hard to answer production questions on a forum.
But maybe Santa is looking at these forums and can help? If Santa does answer back, Please ask Him about My 4.0GHz BS2 I've been asking about for years now.
Thanks
Just Kidding: Merry Christmas/happy holidays
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The Truth is out there············___$WMc%___···························· BoogerWoods, FL. USA
Post Edited ($WMc%) : 12/24/2009 1:13:05 AM GMT
Frankly, though, I consider the BS2pe to be the king of the BASIC Stamps in terms of features and speed vs. power consumption. I've never really regretted not having a MoBoStamp-2p to offer.
-Phil