part 1: I've a quick question or two for ya... (well, actually a few more than that...) Just downloaded Paul Brogger's (excellent) instructions for the memory upgrade for HP42s and being the (proud) owner of one, would like to upgrade mine! I did a bit of research for the 62256 RAM chip, and found enough info to thoroughly confuse me. (I'm a Surveyor, not an Electronics Engineer) I understand I should look for SURFACE MOUNT, and LOW POWER, but it seems that there are several versions of this chip out there. Price isn't much of a factor; it seems they run anywhere from about $2.50 to $15 each. Some are DRAM, some are SRAM, and some are listed as CMOS RAM. How about the speed of the chip? They are spec'ed as anywhere from 45 to 100ns. Most seem to run about 70ns. Paul's article doesn't state which he used/need for his in the article. Does it matter/Is there a difference? Most suppliers want a large order - i only need one! Any suggestions on where to go pick one up in the area around San Bernardino in Southern California? How is the case reassembled after the mod to prevent it popping open again afterward? I'm a Land Surveyor; my 42 gets some rough use. Thanks for any feedback you can provide! I just want to make sure i get it right the first time, 'cause i use my little buddy a LOT and would be lost without it!

part 2: I would also like to run Christoph Geisselink's EMU48 with the HP42s romdump. I have 3 HP42S calculators, so i have one available for the ROM dump. I have downloaded the CPROMUPL.ZIP file, and it seems very complete, but I need to ask if it can be done using an HP50G, which I have, instead of an HP48GX. Is BINPRT hardware dependant, or will it run on an HP50G? The HP50 has more than enough memory, and an IR reciever port, so if the BINPRT will run on it, it seems there should be no problem. If it won't, then does anyone have a procedure you could suggest for using the HP50G in this case? Thank you very much for this help.

p.s. - my collection of HP calculators is the following: Hp11C, HP28C, HP32S, HP33S, 3 HP42S, HP48SX (no memory card - not big enough for ROMDUMP, i think) and an HP50G. I used to own also an HP41C, an HP41CV, and 2 HP41CX, but i sold them to buy an HP48GX and 1 meg memory card, which was then stolen... I don't know which was the greater loss.

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Most suppliers want a large order - i only need one!

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Once I needed a particular kind of rocker switch, not readily available at your local Radio Shack, for a hobby project. I found what I was looking for by diligently searching online. I emailed the manufacturer inquiring about the cost. Same deal, they were only set up to sell large quantities. Without my even asking, some kind soul sent me a couple of them as free samples, no shipping charges, nothing. I'm not sure if they thought I was an OEM or what, but I did not object to the generosity.

It needs to be SRAM (static RAM). It needs to be CMOS, but I don't think you're likely to find any other kind these days. There used to be NMOS RAMs, but I'm not sure if any NMOS 32K*8 parts were made.

You could try the Cypress CY62256VNLL-70SNXI, available from Digikey in quantity 1 for $2.25. Note that I have NOT verified that this part will work in a 42S. I think it will, but there is no guarantee.

Digikey will charge a $5 handling fee if you don't order at least $25 worth of merchandise.

I strongly recommend against attempting the upgrade if you aren't accustomed to building and repairing surface mount electronics. I have some SMT experience, but I would be reluctant to upgrade my own 42S. They weren't designed to be taken apart and reassembled, and are not going to be as mechanically robust after doing so.

Do NOT use CY62256VNLL-70SNXI without special care (more modification needed).

VN suffix means low voltage (2.7-3.6V) version, and its absolute
maximum rating of the supply voltage is +4.6V.

The voltage of fresh 3xSR44 often exceeds 4.7V,
it may causes the latchup of the devices and may result in severe destruction.

The following (cypress's) devices are recommended.

CY62256LL-70SNC  (4.5-5.5V, Low power, 70ns, SNC28-300mil, Commercial)

CY62256LL-70SNI  (4.5-5.5V, Low power, 70ns, SNC28-300mil, Industrial)

CY62256LL-70SNXC (4.5-5.5V, Low power, 70ns, SNC28-300mil, Pb free, Commercial)

CY62256LL-70SNXI (4.5-5.5V, Low power, 70ns, SNC28-300mil, Pb free, Industrial)

CY62256LL-55SNC  (4.5-5.5V, Low power, 55ns, SNC28-300mil, Commercial)

CY62256LL-55SNI  (4.5-5.5V, Low power, 55ns, SNC28-300mil, Industrial)

CY62256LL-55SNXC (4.5-5.5V, Low power, 55ns, SNC28-300mil, Pb free, Commercial)

CY62256LL-55SNXI (4.5-5.5V, Low power, 55ns, SNC28-300mil, Pb free, Industrial)

is the 32K the same chip that uses the HP48G??

thanks

Yes. Various brands were used in the 48G:

Fujitsu MB84256-70LL 

Sony    CXK58257AM-70L

Winbond W24257S-70LL

I have 32k chips pulled from 48G's if anybody wants one. Just send me an email.

YOU GUYS ARE DA BOMB!!! Ok!! that answers most of the memory upgrade questions. I found a source for the correct Cypress chip, and ordered one. THANKS BUNCHES, guys! Thanks also to Lyuka for the photos on the website! Those answered a few more of the "mechanical" aspect questions. I'm confident i can do this now. As long as I use a Temp controlled soldering iron set to 230 degrees, the silver-loaded solder for surface-mount apps, don't exceed 10 seconds of heat, and use a pair of small surgical clamps for a heat-sink while soldering, i should have NO trouble at all with the electronics. As for the case reassembly, it appears the heat stakes are hollow, so I should be able to find some short, oval head, phillips machine screws that will fit nicely and hold it together. It LOOKS like I would only need them at the top end of the case, so I don't need to worry about peeling the foil back to expose those at the bottom...maybe. Anyway - I think I have all the info i need to try it, now.

So, the only questions remaining are those in 'part 2' about using an HP50G to download the 42s ROM image... Anybody got any ideas there?? <grin>

Thanks again! polarbear Mike

Edited: 17 Jan 2008, 12:46 p.m.

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part 2: I would also like to run Christoph Geisselink's EMU48 with the HP42s romdump. I have 3 HP42S calculators, so i have one available for the ROM dump. I have downloaded the CPROMUPL.ZIP file, and it seems very complete, but I need to ask if it can be done using an HP50G, which I have, instead of an HP48GX. Is BINPRT hardware dependant, or will it run on an HP50G? The HP50 has more than enough memory, and an IR reciever port, so if the BINPRT will run on it, it seems there should be no problem. If it won't, then does anyone have a procedure you could suggest for using the HP50G in this case? Thank you very much for this help.

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No, the HP50G isn't useable, neither from the IR receiver hardware nor from the INPRT software.

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p.s. - my collection of HP calculators is the following: Hp11C, HP28C, HP32S, HP33S, 3 HP42S, HP48SX (no memory card - not big enough for ROMDUMP, i think) and an HP50G. I used to own also an HP41C, an HP41CV, and 2 HP41CX, but i sold them to buy an HP48GX and 1 meg memory card, which was then stolen... I don't know which was the greater loss.

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The HP48SX is your choice. As I described in the Clamshel.txt file it's possible to load the ROM in pieces and finally put them together on the PC. For the HP48SX four pieces with 16KB each are best. You can call the program four times, the only difference in program is the start address where to begin. The ROM dump program in the HP42S normally persists the warmstart at program end when you're using my suggested base address. So you only have to recall the program, modify the start address and upload the next 16KB block. The converting and merging the blocks is described in the Clamshel.txt file.

The following is a modified dump (sorry not tested) for uploading the HP42S ROM in 16KB blocks

Saturn Assembler    Dump Lewis Pioneer ROM over IR     Thu Jan 17 01:52:53 2008

V3.0.8 (12/06/2002)                                      ROM42.a        Page    1

            * Send character in A[B] over IR

            *OUTBYT         EQU     #0133C  (HP17B   rev. A)

            *OUTBYT         EQU     #01378  (HP17B   rev. B)

            *OUTBYT         EQU     #01445  (HP17BII rev. B)

            *OUTBYT         EQU     #0136A  (HP27S   rev. A)

            *OUTBYT         EQU     #0142E  (HP27S   rev. B)

            *OUTBYT         EQU     #0318D  (HP42S   rev. A)

            OUTBYT          EQU     #031D6  (HP42S   rev. B/C)

            * no. of 128 byte blocks

            PRGLEN          EQU     128     16KB block

00000 1F000         D1=(5)  #00000          ROM Start address

      00

00007 D1            B=0     A               init block no.

00009 E5    -       B=B+1   A               inc no. of blocks

0000B 7110          GOSUB   SBLOCK          send block

0000F 32F70         LC(3)   (PRGLEN)-1      no. of 128 byte blocks

00014 B39           C=C-B   X

00017 51F           GONC    -

0001A D2            C=0     A               restart

0001C 81B3          PC=C

00020 D0    SBLOCK  A=0     A               SOH block header

00022 E4            A=A+1   A

00024 7D20          GOSUB   SBYTE

00028 D4            A=B     A               block number

0002A 7720          GOSUB   SBYTE           send data byte

0002E D4            A=B     A               1' complement of block number

00030 FC            A=-A-1  A

00032 7F10          GOSUB   SBYTE           send data byte

00036 AF2           C=0     W               reset checksum

00039 34000         LCHEX   #7F000          loop 128 bytes, chk = 0

      F7

00040 14B   -       A=DAT1  B               get data

00043 171           D1=D1+  2               next address

00046 A62           C=C+A   B               add checksum

00049 7800          GOSUB   SBYTE           send data byte

0004D A5E           C=C-1   M               next byte

00050 5FE           GONC    -

00053 DA            A=C     A               send checksum, fall into SBYTE

00055 10B   SBYTE   R3=C                    save byte counter/checksum

00058 D9            C=B     A               save block couter

0005A 10C           R4=C

0005D 8F6D1         GOSBVL  OUTBYT

      30

00064 11C           C=R4

00067 D5            B=C     A

00069 11B           C=R3

0006C 01            RTN



- Block1 (16KB)

00000 1F000         D1=(5)  #00000          ROM Start address

      00

- Block2 (16KB)

00000 1F008         D1=(5)  #00800          ROM 2nd block

      00

- Block3 (16KB)

00000 1F000         D1=(5)  #01000          ROM 3d block

      10

- Block4 (16KB)

00000 1F008         D1=(5)  #01800          ROM 4th block

      10



- HP42S ROM Rev. A

0005D 8FD81         GOSBVL  OUTBYT

      30

- HP42S ROM Rev. B + C

0005D 8F6D1         GOSBVL  OUTBYT

      30

Christoph

Hi again! Christoph, YOU DA MAN!!! It worked perfectly - after i found and downloaded Kermit for the HP48sx - CONN4x doesn't work with the 'sx... (learned the hard way, LOL). Thank you VERY much for the additional instructions for the ROM dump. I now have a fully functional emulated HP42S on my desktop, and it works perfectly!

I had an idea I would like to ask you about. The 42S ROM will, if the PRON command is given, try to send the output to the IR port for printing - In the real 42S there IS an IR port, so everything works as advertised. In the EMULATED 42, however, there IS no IR port, so 1) what happens to the output stream? and 2) is it possible to use it as input for a program (as yet unwritten) that would emulate an IR printer? That program could generate a plain text file (say, in notepad) which could then be saved. Having notepad open alongside the emulated 42s, you could see the printer output immediately, and then save-as whatever filename you want. That way, programs could be listed out, and in my case, paper listings of calculated coordinates could be saved. My program COGO-42 will print to an IR printer to do this, I just don't know how to do it with the emulated 42.

Thanks again!!

polarbear Mike

P.S. - If anybody wants copies of my COGO-42 programs, which is well documented with instructions, and includes the program listings, just drop me an e-mail to polarbear_mike@yahoo(dot)com. I'll be happy to send you the PDF file, and if you wish, i can also send you the RAW files from Christoph's HP42s emulator!

pbM

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The 42S ROM will, if the PRON command is given, try to send the output to the IR port for printing - In the real 42S there IS an IR port, so everything works as advertised. In the EMULATED 42, however, there IS no IR port, so 1) what happens to the output stream?

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It get lost. The IR transmitter LED is controlled by a bit in an ouput register. On Emu42 this bit isn't emulatated.

This was the simple answer. I already tried to decode the output stream and put the result into a console window many years ago. This works for the HP42S but not for the HP28S. I know the reason (a problem deep inside the timer2 emulation), but I don't know how to solve it.

Christoph

It get lost. The IR transmitter LED is controlled by a bit in an ouput register. On Emu42 this bit isn't emulatated.

This was the simple answer. I already tried to decode the output stream and put the result into a console window many years ago. //This works for the HP42S but not for the HP28S.// I know the reason (a problem deep inside the timer2 emulation), but I don't know how to solve it.

BUMMER. Oh well, a man can dream... Thanks for the response, though, Christoph. You say above that you can take the output into a console window for the 42s but not for the 28s?? That would be fine with me - i'm using the EMU42 as an hp42s, not a 28s. How would I do that? Sounds like an acceptable way to get what i need - not as functional as I had hoped, but workable nonetheless. Thanks again!

pbM