voltage on each port & pins

[hsukiang]

hi,

i have this problem executing my hex file.
aft i have X8000 on the maxterm, there is a long pause.
i use a DVM to check the voltages on all the pin of port 1. and it all gives 6V.
as my program is suppose to alternately make the pins goes high(6V) and low(0v).... I cannot turn down the voltage.

would appreciate if u can suggest some idea to solve my problem. perhaps i missed something out?

thanks alot.

[nmitech]

Does your board have a regulator on board? If so please check make sure the part is labeled 7805 not 7806.

What kind of power supply or transformer are you using?

Where do you connect the power on board, J2 or J12, etc..?

[hsukiang]

Does your board have a regulator on board? If so please check make sure the part is labeled 7805 not 7806.

yup 7805 bt it gets awfully hot, so i guess it must b sucking up loads of current.


What kind of power supply or transformer are you using?

its an unregulated adapter (transformer) and derive power fr the main power line, 240V 50Hz.


Where do you connect the power on board, J2 or J12, etc..?

its connected to J2

[nmitech]

its an unregulated adapter (transformer) and derive power fr the main power line, 240V 50Hz.

What is your transformer output rating?
Output rating suggestion: 7.5V to 12V at 300mA or higher.
Yes, the regulator will get hot even at the suggestion voltage because the NMOS microprocessor and the entire board current requires is about 250mA. If you do a Power calculation of the voltage drop across the regulator and the current requires by the entire circuit then there is no supprise if the 5V regulator is hot. So use transformer with lower voltage output if possible, 7.5V minimum and add heatsink for the regulator to prevent the regulator shut down when it is too hot.

[hsukiang]

hi there,

i have checked my transformer and also the 7805, its all in working order.
however i still get 6V all the time on port 1...
even though i run my hex file, its still 6V all over.

any suggestion for me to troubleshoot this problem?
sorry i so inexperience in these things.
bt plz advice as much as possible.
thank you

[nmitech]

its still 6V all over. any suggestion for me to troubleshoot this problem?

Check the output of the 7805 regulator, make sure it shows 5V, if not then replace with the new 7805. Also use 8V up to 12V DC transformer the most for better result.