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latigerlilly
02-02-2007, 04:50 AM
Hi guys,

Please look at a pic of my PDB before I hook it up so I don't blow it up. I have a PDB with a BS2P40. Also, I just have a few quick questions;

1. My BOE-BOT used a 6 VDC power supply. My PDB has a 9 VDC power supply. Will the PDB automatically regulate the voltage difference between Vdd and Vss to be 5 VDC? In other words, "Don't worry about it?"

2. The on/off switch on my BOE-BOT is a switch with 3 positions, "0, 1, and 2". Position "0" is off, "2" is for servos, and "1" is for everything else. On the PDB, the on/off switch is just "off" or "on". So, just consider it to be equivalent to the BOE-BOT "0" or "2", respectively?

3. How come on my BOE-BOT there is only 1 row of I/O pins (P0 to P15) and one row of Vdd, Vin, and Vss pins? But on the PDB, there are 2 rows of I/O pins, Vdd, Vin, and Vss? In other words, on the BOE-BOT, there is just one P1 pin, but on the PDB, there are 2 P1 pins. You can only actively connect an I/O pin to one device anyways. Is the extra pin there for flexibility only?

4. How come there are 2 sets each of Vss, Vdd, and Vin pins? Again, they are just there for flexibility?

Pic of my PDB with BS2P40:
http://i15.photobucket.com/albums/a371/MINGMAY/pdb-1.gif

Thanks,
Lilly.

Post Edited (latigerlilly) : 2/1/2007 10:00:02 PM GMT

Zoot
02-02-2007, 10:17 AM
Somebody said...
1. My BOE-BOT used a 6 VDC power supply. My PDB has a 9 VDC power supply. Will the PDB automatically regulate the voltage difference between Vdd and Vss to be 5 VDC? In other words, "Don't worry about it?"


Both boards tie Vin to a 5volt regulator -- the thumb-sized black epoxy chip with three pins mounted in a heat sink (black metal with little vertical fins) at the top left-ish of your PDB. The voltage regulator accepts ~6-12v and will deliver 5v to Vdd. The boards are not rated to 12v because a lot of 12v batteries at full charge will deliver in excess of 13 volts AND on the boards Vin is applied to yet ANOTHER tiny voltage regulator that is on board the Stamp itself. You don't have to worry about it, but you should know. The Stamps have two positive power pins -- Vdd and Vin. If Vin is connected to > 5.5v or so, then the Stamp and it's pins are powered by 5v out from it's own onboard regulator. This regulator only delivers 50ma or so, while the big regulator on your PDB delivers nearly 1000ma. If you apply power to Vdd, it needs to be an *already* regulated 5v. In the case of my projects that don't use a dev. board, I run my >12v battery power through a well heat-sinked 2A 5v regulator which powers all my electronics, Stamp, etc.


Somebody said...
2. The on/off switch on my BOE-BOT is a switch with 3 positions, "0, 1, and 2". Position "0" is off, "2" is for servos, and "1" is for everything else. On the PDB, the on/off switch is just "off" or "on". So, just consider it to be equivalent to the BOE-BOT "0" or "2", respectively?


Yes, essentially. But the Boe-bot BOE presumes ~6v Vin and the Vin is applied as the + power on the servo headers -- in other words, on the BOE, the servo power is the raw battery power. Using a Vin greater than ~6-7v would destroy many servos. A lot of folks will run their servos at 5v from Vdd if the regulator(s) are up to the task.


Somebody said...
3. How come on my BOE-BOT there is only 1 row of I/O pins (P0 to P15) and one row of Vdd, Vin, and Vss pins? But on the PDB, there are 2 rows of I/O pins, Vdd, Vin, and Vss? In other words, on the BOE-BOT, there is just one P1 pin, but on the PDB, there are 2 P1 pins. You can only actively connect an I/O pin to one device anyways. Is the extra pin there for flexibility only?


Yes, conveniences.


Somebody said...
4. How come there are 2 sets each of Vss, Vdd, and Vin pins? Again, they are just there for flexibility?

Ditto.

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