frosting

Hi All !
I am new in this forum so firstly I would like to say Hello
 
About half year a go I was looking for MSP430 Bootloader for value line like MSP340G2553, unfortunately I was not able to find anything.
Now when I entered this forum I see that there ware some works around this topic.
 
Nevertheless I would like to share with you my MSP430 Bootloader which I was able to do from scratch using TI datasheets.
It is not fully tested yet, but with simple "Hello world " program it works.
 
Detailed description and svn repository you can find on my WIKI here:
https://daniel.duchna.pl/index.php/Msp430_bootloader
 
Please feel free to test it and any comments are welcome. 
You can post here or add comments on my WIKI (after registration)

It's not bad, either positive or negative requires pretty much the same treatment. I have designed many products used in autos and trucks. A resistor, a capacitor, and a Zener diode is ample protection for an input pin. If you are using the internal pullup or pulldown in the MSP430 then it might influence the choice of resistor value, use a higher value if you are sensing a 12V signal(4.7K or 10K is fine). But the basic three parts are all you need. Use a white or blue LED if you don't have a 3.3V Zener. Or two reds in series.
Regards, Bob

Isn't the PCF8574 an I2C to 8-bit interface? The HD44780 display has a few control lines in addition to data, so you are probably running in 4-bit mode, with 4 of the pins for data plus RS, RW and EN. Each character will take two complete transactions. And the EN pin is how you clock in each byte. If you have the EN pin connected to your PCF8574 you will need four I2C instructions to print one character. If you clock the display separately from the PCF8574 then it only takes two I2C writes, but they need to be interspersed with clocking of the display's EN pin.

No need to use a sine wave. Generate square waves with the MSP430. One end of your sensor goes to the pin with the square wave, the other to the midpoint of a voltage divider of the MSP430 power supply. Tie the input of an A/D channel there, take measurements at both polarities of the square wave and subtract one from the other for the net voltage. Essentially a bridge circuit, your unknown is working against the impedance of the voltage divider. If your resistors are 2K then the impedance of the divider is 1K. Choose the resistors to scale the sensor gel. If the impedance is too low you will load the MSP430 output, too high and the A/D converter will have offset errors (and S/H errors if you use more than one channel). All of those problems can be worked around with more parts, but you have the basis for a full system of one channel with only two resistors, two channels with only four resistors.
 
Make sure you never stop the square wave unless you turn the pin into an input! Else your sensor will have electrolytic damage.
 
Hope this helps.