43oh

# ROFLhoff

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1. ## Multi-battery Voltmeter

I figured that I can get away without using some form of over voltage protection, as I planned on a line of battery slots that could only fit AA and AAA sized batteries. The only time a voltage outside of the range of +/-1.5V is if the user found a lithium battery for that size, and the worst case is that battery is 4.2V. That would be the only case of over-voltage, but let's look at how the circuit would handle such cases. There are a few assumptions for the circuit: Supply Voltage is 3.6V Series Resistor is 1K ohm Built-in diode drop is 0.3V Those diodes would consume (4.2 - 3.6 - 0.3V)
2. ## Multi-battery Voltmeter

@@voodoofish, I setup P2.6 & P2.7 as button inputs. I forgot to edit that picture, but I didn't use an LM317 as a regulator. I used a regulator from Texas Instruments, something in 5-pin sot package. @@grahamf72, thanks for the sample circuit. I looked at the protection diodes built into the microcontroller, and they can drop something like 0.3V but only handle 2-3mA safely. I think I can get away with a 1k/100K divider like your circuit, but ditch the zener that way. Is the mux resistance of the ADC taken into account when processing the result? Does it load the newly created voltage
3. ## Multi-battery Voltmeter

Hey guys, thought I'd post something I made this month to learn about interrupts and state machine coding. This project just measures up to four sub-1.5V batteries and shuts down after four seconds. I chose to not have the project run off the batteries it tests. I had a ton of 18650 lithium cells, and used one. I had a little trouble thinking of a way to power the LCD as it really needed more than 3.6V to read any characters on it. Using a lithium cell is convenient as the screen is nice and legible throughout a big portion of the cell's working voltage. As of right now, the whole circuit cons
4. ## Procedure to restore SegmentA Calibration Data?

Thanks for the reply, I took a deeper look at the MSP430x2xx User Guide (AKA SLAU144) and the G2231 datasheet/errata) and looked at the TLV section. It looks like the constants CAL_ADC_15T30 and similar can be found with a temperature-controlled enclosure, but might need two other constants to be set correctly: Offset and gain factor calibrations. The User Guide only demonstrates using those constants to correct raw ADC values, and I don't see a way to work backwards for the constants. Unless I'm reading the section wrong(SLAU144j: 22.2.4-5) there are two variables to adjust from only
5. ## Procedure to restore SegmentA Calibration Data?

Hey guys, it's been a long time since I've used launchpads, and am re-learning some specifics with the value line chips. I had a couple G2231 chips laying around that I used to run a cheap HD44870 display to show the ADC10 Channel 10 & 11 readings (Temp/ .5Vcc). I also wanted to see the calibration data to understand how to use that for more accurate readings. Somewhere along the lines I had ran the TI dco_flashcal.c program on them so those values are gone. My question is how those values were made in the first place? Did TI throw their chips in a 30C/85C environment and sampl
6. ## Color LCD Booster Pack

Quick question, What is the spacing between the EEPROM pads? 208mil or 150mil? Keep up the good work!
7. ## Hello guys

First off I'm not the kind of guy to post hellos and such, but it seems like my account keeps getting erased from the system every couple of days. Does the forum delete people with no posts? Anyways, happy to be here and hope to contribute soon.
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