Problems with repurposing the HP20b/30b



#2

Hi All,

I have been trying to burn the wp34s on an HP20b and an HP-30b. Gene Wright has kindly mailed me the old serial port cable that connects a PC with either calculator model.

At first I try to use an serial-to-USB adapter cable with Gene's cable to connect my current laptop (running Windows 7) to the calculator. That did not work. No real surprise here.

I then bought an old IBM Thinkpad laptop with Windows XP. I used the same cable system to connect the laptop's USB port to the calculator. That did not work either.

Last night I found in my house and old compact PC that has the old serial port and runs Windows 2000. I powered the old PC up, got to work, and copied the related firmware burning files to that old PC. I then used the serial cable that Gene sent me to connect the old PC and either calculator model. It DID NOT WORK EITHER.

I am using SAM-BA version 2.10 that I got from Gene to burn teh firmware. The cable he sent me was able to easily and quickly erase HP's firmware on the 20b and 30b. But when it comes to burning the wp34s firmware, I am getting a message that the software did not connect with either calculator. In the case of the SAM-BA 2.10 it sees COM1 and am able to select the board type (following a new instruction file I got from Gene) but it is unable to make the connection with either calculator.

Any help is appreciated. What am I doing wrong? Is the Windows 2000 not helping? Do I need to press the Reset and ON button in a particular order and duration before I run the SAM-BA 2.10 application?

Namir


#3

In order to get it to work on with an USB to serial adpater choose one from FTDI. The prolific chips don't work. I've tried it on Windows XP without success.

The erase feature is totally independent from the serial port, it's just a pin on the chip which is tied to high while the processor is running. Once erased, the only software in the device is the SAM-BA boot loader. After the erase, you need to reset the processor and then turn it on again. While not experimenting with it remove the batteries!. SAM-BA has no provisions to turn the device off and makes no attempt at saving power. It may be that your batteries are already flat.


#4

Thanks for the tips. I did take the batteries out of both machines. I used a voltmeter to test the batteries and they seem ok. Whem I put the batteries back and tried to burn the 30b .. IT WORKED!!!I have a wp34s flahsed. YEAAAAAAAAAAAAHHHHHHHHHH!!!

Thanks

Namir


#5

I've re-flashed the 20/30b/12c+/10bii+ many, many times and have also found that a battery pull is frequently "the fix" when I have trouble with a firmware downloaded.

The other tip I'll offer is to pull out and reinsert the 6-pin pogo connector. Sometimes those pogo tips don't make good contact with the pads on the PCB.

I really wish that the firmware download process wasn't so difficult with these ARM machines. The whole system seems inherently problematic: built-in ARM boot routine, the PC software, USB to serial converter, the pogo-pins and the high current draw needed ROM these small power cells, not to mention user error.

I realize that HP never intended these programing ports to be used so frequently, but now that they are the whole process is in need of a makeover. Any suggestions?


#6

Katie,

Thanks for your tips. I will try them. I stayed up last night until 2:30 am working with the old PC and trying to burn the firmware. After getting getting the tip about the batteries from Marcus, the SAM-BA software connected and I was able to burn the 2p34s. My wife's nephew (who is staying with us to study locally) was kind enough to put the overlay labels that I had bought from Eric.

I agree wholeheartedly with you about how complex the setup is. I wish Cyril would write a firmware-burning program that works smoothly with Windows 7 and the USB ports.

Again, thanks for the additional tips.

Namir

#7

Welcome to the club :-) I hope you enjoy your 34S.


- Pauli


#8

It's a beauty, especially with the overlay. I bought another 30b so I can alternate the updates between 2 units. This way I always have one machine at least that works.

Namir


#9

Quote:
This way I always have one machine at least that works.

Such a lack of confidence !


- Pauli


#10

Well the cable that burns does not work reliably. It's like gambling in Las Vegas. What can I say?? Wiping out the firmware is by far the most reliable part of the whole operation. Writing the new firmware is a major gamble. Your software is cool and I would like to be able to update the firmware, without having to harass Gene Wright (the man has been very patient and most cooperative with me).

:-)

Namir

PS: I was showing my wife the wp34s calculator. I had a smile from ear to ear. You guys did a fantastic job.

Edited: 13 Aug 2011, 10:01 p.m.


#11

Not directly related, but . . .

Last night -- just for the heck of it -- I tried re-flashing both a 20B and a 30B with my early 2008 MacBook (OS X 10.7 Lion), running Windows XP inside a Parallels 6 virtual machine. I used a USB-to-serial adapter cable which is not branded with any name or other identifying information, which I found in a box of computer cables in my garage. Although I didn't expect it to, I was pleasantly surprised that this combination worked!

Stephen


#12

Good to hear. The Mac System-Profiler should tell you more about the cable. Can you post the vendor id here?


#13

Here it is, Marcus:

USB-Serial Controller:

Product ID: 0x2303
Vendor ID: 0x067b (Prolific Technology, Inc.)
Version: 3.00
Speed: Up to 12 Mb/sec
Manufacturer: Prolific Technology Inc.
Location ID: 0x1d100000 / 2
Current Available (mA): 500
Current Required (mA): 100


#14

So it's one of the Prolific devices that work. Interesting find.

#15

Hey Namir! Don't go letting people think I'm patient and helpful! :-)

Glad it has worked.

#16

Apparently something has changed, because prolific chipset converters were the only USB<=>serial sevices I ever could get to work reliably with all my serial stuff (long before I started for HP). My adapters work just fine.

They are several years old though. Someone else I know bought one recently and just had a terrible time getting it to work. No exactly conclusive, but I sure see a lot of people complaining about them online now. . . :-(

TW


#17

the problems with USB to serial bridges based on the Prolific chip, the PL2303, are twofold:



(1) chinese manufacturers have cloned the PL2303 chip design and are supplying 'fake' devices that only work with certain versions of the drivers - they never developed their own, relying on consumers downloading the drivers from Prolific. the silicon implementation in the fakes is far from perfect, and Prolific have responded by making their drivers try and detect the fakes and refuse to work with them.



(2) the PL2303 was originally designed to be an 'all in one' solution, able to drive and receive RS232 signal levels without the need for a level shifter (such as a MAX232). even the genuine devices do this very poorly, so most reputable manufacturers pair up the PL2303 with a line driver/receiver. needless to say, the cheap bridges you buy on ebay for a couple of dollars out of china don't bother with the line driver/receiver.



if either (1) or (2) hold, you have little hope of any success. BUT, if you can get a bridge that uses a real PL2303 and uses a separate line driver/receiver, then it will work as good as any other (such as an FTDI or Silicon Labs CP2102 based bridge).


Edited: 16 Aug 2011, 4:15 a.m. after one or more responses were posted


#18

Chinese crap, sigh! When will they start to sell fake FTDI devices?

For SAM-BA to work, the chip must reliably support 115 Kbps.

Namir, once flashed with 34S there is no need to press the Erase button on the cable, just do ON+D and ON+S (the latter twice).


#19

They sell fake everything else.

That one is awesome -- it is worthwhile to manufacture a fake controller chip just for this. I imagine the fabrication costs for the chip are huge so these things must sell very well.


- Pauli

Edited: 15 Aug 2011, 4:00 a.m.


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