not able to communicate with isopod

[subot.robot]

I took out 4 isopods which were there in my lab. I have worked with servopod but not with isopods. I connected them to pc using serial cable and powered it. they are v2 isopods with development kit. out of the 4 one is not working as light did not turn on when i powered them. I have set nmiterm to com1, and tried all baudrate from 9600 to 115200 . i have also put a jumper to short pin 2 and 4 of J5, to prevent existing program from autostarting. In all the baudrates, 3 isopods are sending some garbage to nmiterm. the settings on nmiterm are
parity - none
databits - 8
stopbits - 1
dtr - on
rts - on
echo - off
flow control - none.
i also went through the isopod document and forum regarding this. i have not been able to make out what is wrong. it was supposed to work for 115200 baudrate.
yesterday i some how was able to communicate with 2 isopods after trying out with different setttings, they were working at baudrate of 9600, and i was able to run a led blinking program which i had written for servopod on them. today i took them out to do more programming and i am not able to get it to communicate, all 3 of them are sending garbage to nmiterm, different garbage for different baudrate, even at 9600.
Please help me to know what might be wrong.

Regards
Subot.robot

[subot.robot]

I am still trying to figure out the problem. I downloaded and installed the latest nmiterm software on another computer and connected isopods to them, without making any change in the setting. To my surprise 2 out of 3 isopods worked and i was able to switch on and off the leds. i disconnected the isopods to test on my first computer and it did not. Back to second computer , now it did not work when i connected them second time. it started outputing garbage instead of isomax version on powering up. I did not make any change to setting and still it did not work. This random nature of working has left me clueless of what might have gone wrong. i checked with 2 different serial connector cable with no change in result. Looking forward for possible solution.
When it worked the baudrate was default baudrate of 9600, (all the settings were default after fresh install)

Regards
Subot.robot

[nmitech]

If it has not something to do with the baudrate then it maybe the program you loaded, or preloaded by other maybe? Try this to eliminate the problem,

- Use Hyperterm on your PC instead of NMITerm. You may have to play with the baudrate settings either 9600 or 115200, if you do not know for sure what IsoMax version is loaded on those IsoPods. You probably won't be ale to download the application program with the HyperTerm but you should be able to use the keyboard and communicate with the IsoPod manually.

- Short out pin 2(GND) & 4(PE4/CLK) of J5 and reset or recycle the power to get the IsoMax prompt if the previous application program is present.

- If you have IsoPod V1, besure to remove the jumper J2 on the carrier board.
(Hint: IsoPod V1 has no mounting hole, and V2 has two mounting holes at the end)

- Have any other power supply or transformer to try out.

[subot.robot]

Hi nmitech,
thanks for the guidance,
The problem seems to be with power supply. It seems like it was getting reset continuously. I am using a variable ac to dc converter and i had set it to 6v and it was giving 5.5v at no load
when i powered the isopod i used to get "Isý" message continuously. And to my luck it started working yesterday evening. again today morning it started giving the same old problem. so i got the hunch that it was getting reset contiuously due to low voltage as i read in doc that i should supply 7-9 v to the power connector of development kit. so i increased dc voltage to 7v and "IsoMý" appeared on nmiterm sometimes and i got IsoMax V0.6 . So i have concluded that it was the problem with power supply as mentioned by u. Thank u once again for helping me out.
But won't the voltage regulator get heated up if i give higher voltage. what is the maximum input voltage i can give to isopod without getting voltage regulator over heating. And what is the minumum input voltage i can give to isopod without getting this problem of resetting. I have to power the isopod from battery when it sits on the robot.

Regards
subot.robot

[nmitech]

what is the maximum input voltage i can give to isopod without getting voltage regulator over heating.

6-9Vdc is appropriate supply. 5V Regulator may be hot to the touch but no heat sink required.


And what is the minumum input voltage i can give to isopod without getting this problem of resetting.

6V at 300mA or higher. 'Pod can still work as low as 5.5V with the LM2937-5.0 part installed.