mchew, please check the following, a couple of the pins on your max232 look as though they may have poor solder joints, make sure that there's enough solder to connect all traces. double check your capacitors next to the max232 for correct polarity.........
BTW whats the jumper for on the board ?
mrchew, Please take the time to read the thread "Pauls HP UHU drive project", I made many errors that pertain to what your having. I received many great answers that may help you. it's not that long & has a wealth of information.................
i remind you that you must connect the usb cable.But if you receive the message from uhu then you have probably done it have you check the tx line on the rs232 with an ohmmeter?
okay, i'm leaning towards a cold solder joint myself. i will recheck each of the pins. they looked good from the bottom but they do seem a little dry on the top.
for the capacitors (in the kit) around the max232, i see a small plus sign with a stripe that looks like a "]" with the bottom cut off. i have this "]" stripe towards the "+" mark on the board.
is that backwards?
(it never occurred to me that this could be the negative stripe...)
about the power, i have checked my supply for the board (a hefty 12v 2A power transformer from commercial audio equipment) and the 5v from the computer. both look great and show no fluctuation (at least that is visible on my multimeter).
I had pondered getting an rs232 breakout box just to check the serial cable, but i doubt that i will have much need for one after i get this working. I would build one but i don't want to start another project!
as always, thanks for your help and quick replies.
i look the picture in post 14 your caps are well oriented
15 volts not 12v and 3 Amp Mr. Kreutz advice but this is only a peek need and for your test it's ok the 5V is made from the 15 v through the 7805 the 5v of the pc is just for the rs232about the power, i have checked my supply for the board (a hefty 12v 2A power transformer from commercial audio equipment) and the 5v from the computer. both look great and show no fluctuation (at least that is visible on my multimeter).
Mrchew,
unless you know something I don't you should be powering the HP UHU drive with 15vdc.................... when we changed, it was a problem for me
Paul
thanks for verifying my capacitor polarity!
i did some spot checks on the board with my multimeter. i checked the voltage supply for the max232. all of these are referenced against pin 15 (gnd)
pin 16: 5.08V (USB voltage supply)
pin 2: 9.76V
pin 6: -8.03V
all of these seem to be within the specs that i found on the datasheet here: http://focus.ti.com/lit/ds/symlink/max232.pdf
i also checked resistance through the cable and into the pins on the max232.
pins 2,3,5 on the DB9 showed about 9 ohms resistance through the 5ft cord to the tops of pins 14,13, 15. I didn't think that this was outragous for a 6ft cable.
all of these checks were done to the top of the pins of the max232, so i think that my solder joints are okay. i also checked the legs of the uhu chip to the nearest points on the board and found that the ohm readings were too low to measure.
I didn't think that the power supply was a problem, i had read of people using a pc power supply for them. But just to check (and because i've been wanting one for a long time!) i purchased a 3A 15V lab power supply. i dialed it in really close to 15V, cranked the amps all the way up, and got exactly the same results. we can safely cross power supply off of the list.
I also purchased a rs232 inline tester. I haven't really figured the thing out yet, but i can tell that there is communication on pin 3 because the led flashes as I boot up the uhu. I don't see any activity on pin 5, although it is lit up. i'll have to find a good page on how to use this thing.
i'm really hoping that i don't have to poney up for an o-scope to check this thing out. the cheapest one that i've found used (worth taking home...) is about $300. that'll set me back at least three months!
thanks for your help as always!
i hope that we can come up with some more ideas! i really think that this is a com port problem, but i'm at a loss for what to check next!
used hyperteminal to do some loopback tests at different points in the cable. works on all points in the cabling, showing that data is being transmitted.
i also figured out which led is Tx and Rx. with the uhu plugged in i do see flashes on the Tx line, pin 3 on the db9. the signal is being transmitted from the pc.
i also checked voltages on both sides of the ad1201. 5V on both sides. continuity checks on all 8 pins were good in spite of my sloppy soldering!
also just for... fits... and giggles i swapped out the uhu chip. no change!
man i wish i had the $ for an o-scope about now!
okay. using the loop back test i know that signal is being transmitted to the board.
i'm trying to figure out a way to find out if the signal is getting to the uhu.
i pulled the uhu chip (the microcontroller) and traced the lines out from the AD1201 to the socket. they come in at pins 2 and 3. i place a jumper between those two sockets just to see what would happen, nada.
is there any reason that i can't pop the uhu chip and run a loopback test on that socket?
if i understand completely, once the signal gets onto the board it goes through the MAX232, through the AD1201, and into the UHU microcontroller.
is there any way to check that signal short of an o-scope? loopback test or perhaps an LED between the signal line and ground?
i'm looking into a cheap o-scope, but about all that i can afford right now is pc soundcard based!
mrchew,
I keep thinking the problem is something simple, so simple we can't see it. so forgive my ideas..... you are using the correct version of Uli's terminal program. DOS for DOS based system & the Windows for the Windows based operating system. a last thought, how about making a new copy of the terminal program & reloading it on to your computer ?
Paul
i'm with you paul, i think that its something simple too! especially since its my first build.
i'm beginning to wonder about my max232. i can short pins 13 and 14 and get an echo. however when i short pins 11 & 12 i get nothing!
another strange thing, when i short pins 2 & 3 on th uhu microcontroller i get a bunch of error messages when booting (as expected!) but when i short pins 2 & 3 on the AD1201 it doesnt happen!
i'm still looking for a scope. don't suppose someone wants to vacation in san diego with their scope?
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