WP 34S flashing problem



#2

Yesterday I tried to upgrade my WP 34S to the latest firmware using Harald's USB board. That's the first time I tried to do this since I installed it. I know I should have tested the COM port first, but I didn't (the driver had been successfully installed so I thought it was ok, but I later found out the COM port didn't show up in the WinXP device manager). So, no wonder I got the message "Unable to connect" from MySamba. It behaved the same way in two other computers.

It appears to be a hardware problem. I remember the calculator would reset when the USB cable was connected in USB 1 ports, and sometimes even when connected to a USB 2 port. When I checked the USB board I noticed a small drop of solder between the pins #10 and #11 of the FT230XS chip. I thought I might have dropped it there when installing the board, so I removed it, but this didn't work. But in all application exmples in the datasheet the pins #3, #10 and #11 are connected together, so I shorted pins #10 and #11 again (I don't see this in Harald's pictures, however). I've also checked all connections.

I know Harald checks his boards before shipping them. If there is something wrong, it's due to something I did. I would like to know if there is some troubleshooting steps I could follow, considering this is really a hardware problem. Another question: is it still possible to use the original programming cable when the USB cable is installed? Thanks for any help!


#3

Olá Gerson,

That solder drop doesn't belong there! Compare the pictures in Appendix H.

HTH

d:-)


#4

Please follow the Troubleshooting Guide (Appendix G).

d:-)


#5

Hallo Walter,

I'd done that already, but I'll do it again. Meanwhile I'll get another 30b, better if it comes with all that installed and tested :-)


#6

Well, I've installed 'my' USB board myself, too. All I can say is it's no witchwork but requires a slow hand and some time. Appendix H (Tuning) is fully based on personal experience.

d:-)

#7

Hello Gerson,

sorry to hear you are having problems with the board.


Pins 3, 10 and 11 are indeed connected. The connections are underneath the IC, so you can't see them. When soldering the IC I sometimes end up with pins being shorted by a drop of solder. Usually I remove them, but if this happens to be between pin 10 and 11 (which are connected anyway) I sometimes didn't bother, as it makes no difference to the operation. So it probably wasn't you who left the solder there - sorry about the confusion, I should spend the extra time removing all solder bridges to avoid this in future.

What operating system are you using? Sometimes you have to go to the control panel, open the USB device preferences, and check the box that says "load virtual com port driver". Otherwise you will see the board as a USB device, but no com port.

With the board installed you can still used the original cable if you want to try that.

As to the reset problem, did you have batteries installed in the calculator when that happened? When the board looses USB power, it switches to battery. If there is no battery installed, that will of course result in memory loss.

Hope this helps,
Harald


#8

Hello Harald,

I'm using WinXP 32 and the driver set CDM v2.08.28 (is this the correct one?). The other computers I tried are running Win7 Pro 64 and Win7 32. The COM port shows up when I use my FTDI USB/RS-232 adapter. I'll try again tomorrow.
No problem about the soldering. It just happened I thought I had accidentally shortened the pins together myself. Aesthetically it was fine.
Regarding the reset problem it happened even when BATT was returning 2.9 or 3.0 volts. Lately I was successfully using a cheap USB charger rated 5.4V/800ma. A more sophisticate LG cell phone charger (500mA) didn't work well, even after I changed a 470uF capacitor inside with a 640uF one and installed a 47uF capacitor on the USB board (now removed).

Cheers,

Gerson.


#9

Quote:
I'm using WinXP 32 and the driver set CDM v2.08.28 (is this the correct one?)
Yes, that is the correct one.

Quote:
The COM port shows up when I use my FTDI USB/RS-232 adapter.

That doesn't mean anything. The setting are for each individual FTDI. So you might have the boxe ticked for one, but not the other.


Quote:
Regarding the reset problem it happened even when BATT was returning 2.9 or 3.0 volts. Lately I was successfully using a cheap USB charger rated 5.4V/800ma. A more sophisticate LG cell phone charger (500mA) didn't work well, even after I changed a 470uF capacitor inside with a 640uF one and installed a 47uF capacitor on the USB board (now removed).

Hmm. This could happen if the USB supply dropped in Voltage rather than shut down altogether. If there was something like 2.5V or 3V on the USB port, then that wouldn't be enough to supply the calculator, but the board wouldn't switch to battery yet either.
It might be that the large capacitor you installed caused just that. Normally, if the USB gets disconnected the 5V rail on the board drops in voltage quickly. Allowing the calculator to continue running of the internal capacitors from the time the USB supply gets to low to supply the calculator until the board switches to battery. Now if the 5V rail was to drop slowly, then that timespan would be longer and the charge in capacitor on the calculator PCB might not be enough to keep the calculator running.

Cheers,
Harald


#10

Quote:
Quote:
The COM port shows up when I use my FTDI USB/RS-232 adapter.

That doesn't mean anything. The setting are for each individual FTDI. So you might have the boxe ticked for one, but not the other.


This might be the problem. I only have to discover where to find "USB device preferences" in the control panel, as suggested earlier.

Cheers,

Gerson.

#11

Bart de Boer just reminded me that he had a similar problem and in his case it was the com port setting. He even provided a screen shot:

Thanks Bart!


#12

Thanks! I had tried that already yesterday but had left the box unchecked as this didn't solve the problem. I still have to find how to change the USB preferences though. Plenty of time tomorrow :-)

Thanks again for your assistance,

Gerson.

#13

I've followed the following instructions:

http://www.techrepublic.com/article/viewing-non-present-devices-in-windows-xps-device-manager/6176798

This showed me I had the drivers for a second USB/RS-232 adapter (a non-FTDI one I had tried a while ago). When I uninstalled these drivers and connected your USB board to a USB-1 port, COM4 finally showed up. I kept on receiving the "Unable to connect" message, but after reassigning it to COM2 and restarting Windows it worked like a breeze :-)

Cheers,

Gerson.


#14

Hi Gerson,

glad to hear you have managed to solve the problem!
Also I am relieved it is not a hardware issue. I have had an email about a similar problem, in that case four WP34s stopped working - I hope there is a similar solution to that problem.

Cheers,
Harald


#15

Hello Harald,

I thought this might be due to a hardware problem because I couldn't get it to work in other computers. If such were the case, then it would surely be due a faulty installation, not to the board itself, I have recognized. Lesson learned: after trying a device you won't use anymore, don't forget to completely remove it from your system :-)

Cheers,

Gerson.

#16

Good you made it. So the driver was the cause. Please see pp. 149/150 in the v3.1 manual (footnote 71) or pp. 167/168 in the printed edition (footnote 84).

d:-)


#17

Yes, I had read footnote 84. The page is still bookmarked in my printed edition. I guess there won't be firmware upgrades any time soon. Anyway, I won't reflash my WP-34S again unless I have a working backup unit :-)


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