jjedlins 0 Posted June 6, 2015 Share Posted June 6, 2015 Hello, I started playing with MSP430USB launchpad a few weeks ago. After couple of rather simple exercises like LCD display and 1-wire bus which worked really nice, I decided to play with ADC12. I was surprised to see that when I was connecting +5V or +3.3V to ANALOG1 input (P6.0) my launchpad was disconnecting from my PC and LCD light was going off. The same was happening when I used other analog inputs. When I connected 4,5V battery between Analog1 and GND it was draining really huge current from the battery. Battery ran out flat after a few minutes. Even thought apparently all Aanlog inputs were on short to GND ADC12 was converting. I could see indication LED going off/on when I was connecting/disconnecting voltage from AnalogInput. It looks my MSP430F5529 is damaged, or I am doing something totally wrong. I used example CCS ADC12 projects. Has anyone experienced something similar on any other MSP430? I know there is ADC12 input ESD protection that can short voltages exceeding some certain value... I must check with lower voltages than 2.5V... Thanks, Jacek Quote Link to post Share on other sites
jjedlins 0 Posted June 13, 2015 Author Share Posted June 13, 2015 Hello, ADC12 Lesson learnt. After doing some checks I realized that I damaged analog input while attaching +5V. Max voltage that ADC12 accepts is 3,3V. There is some threshold above which ESD protection diodes start conducting. Of course current which ESD protection can handle is less than +5V pin on the launchpad can provide...I guess close to 500mA. Thus these diodes got broken...Fortunately I have couple more Ax's to use ;-) Thanks, Jacek Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.