HP-20B pics!



#2

Five screws--two are hidden under the rubber foot. Snaps the rest of the way. I made a mess of my faceplate working the snaps. They're tight. I didn't take a pic of the snaps, but I can. Two across the top, three on either side, and one at the bottom.

Crummy overall shot:

Close up of the CPU area:

Close up of the JTAG/programming port:

First impressions? Keys suck. Display contrast could be better. Book is really thin, refers to the unit as "Euro" and mentions the macro facility. Other than the font, the book looks like the scan that was floating around last month. I didn't find the packaging all that easy to open. Doesn't come up in RPN mode.


#3

Thanks for the PICS! I'm curious about the JTAG port.. that would be neat to write one's own OS and use the 20b as the platform!

Got my 20b today too... I put some comments together here along with some specifics like size/weight, and alternatives for calculators and 20b cases.


#4

Quote:
that would be neat to write one's own OS and use the 20b as the platform!

I think that's the idea. I also have a largish (~3MB) pic of the PCB: Link

I was considering starting a Wiki page on it, probably at the elinux wiki. Or is there a better spot to start documenting the hardware?

#5

You don't even need to open the case and use the JTAG port for that. The six electrical contacts accessible in the battery compartment (J31-J36) are a CMOS-level (battery-voltage-based) asynchronous serial port along with the signals needed to use Atmel's "SAM-BA" program on a Windows PC to load your code into the flash memory of the AT91SAM7L128 microcontroller.

You just need six pogo pins (or other spring-loaded contacts) and a level shifter.


#6

Quote:
that. The six electrical contacts accessible in the battery compartment (J31-J36) are a CMOS-level (battery-voltage-based) asynchronous serial port along with the signals needed to use

Looks like the breakdown is:

J31 3V supply

J32 reset

J33 serial out (JP6, pins 11&14 of the optional '232 level shifter)

J34 ground

J35 serial in (JP5, pins 8&9 of the optional '232 level shifter)

J36 guessing it's the erase signal

I still want to use the JTAG port to examine the system in a working state, before I brick one of my units with SAMBA.


#7

No luck on the JTAG. I 'adapted' my 20 pin wiggler to the 16 pin connector on the board, but OCD Commander doesn't recognize the cable when it's attached to the HP20B. (I tested the wiggler and software with an LPC2xxx board, and it worked fine.)

Hmm. I'll double check--maybe I crossed a wire somewhere. OCD Commander is notoriously finicky, so it may be no big deal.

I wonder if there's any serial output at bootup. Need to put a scope on there tomorrow and take a look.


#8

hello

[I wonder if there's any serial output at bootup. Need to put a scope on there tomorrow and take a look.]

don't bother, there is none.

cyrille


#9

Quote:
hello

[I wonder if there's any serial output at bootup. Need to put a scope on there tomorrow and take a look.]

don't bother, there is none.

cyrille


That would have been a nifty easter egg, visible only to the hardcore.

BTW, I messed around and got a little bit of JTAG action. Enough to modify the display buffer. Fun stuff!

#10

1) Log base 10 is present in the machine. Press Shift Math UP.

2) Factorial returns the gamma function for non-integer arguments using the non-integer argument plus 1 as the input to the function. 0.5 ! returns gamma of 1.5.

3) Given that the 20b is a business model, I'm not quite sure what other arrangement you would have liked for the x^2, SQRT, 1/x, etc., functions. :-)

4) It has also been a LONG time since an HP business model had permutations and combinations present.

5) It also has stats functions beyond the probability distributions that have not been on an HP before (?)... standard error of the mean and covariance.


Edited: 18 July 2008, 1:03 a.m.


#11

Allen (Hudendai) wrote:

Quote:
Probability Functions (with inverses) included: normal distribution, Chi-squared, student distribution, and F-distribution.

Gene wrote:
Quote:
It also has stats functions beyond the probability distributions that have not been on an HP before (?)... standard error of the mean and covariance.

Hey, overall it seems HP is listening! Or at least watching and reading :) Good to know all these algorithms are present now, though I doubt many people will dig for or even use them on a calc labeled "business".

So, *please*, when may we expect a scientific model with a menu access like on the 17bii+ Silver? You know where to look for ideas ;)

Edited: 18 July 2008, 2:30 a.m.


#12

Quote:
So, *please*, when may we expect a scientific model with a menu access like on the 17bii+ Silver? You know where to look for ideas ;)

Well put! I can see this coming out by April 2009. If you look at HP's traditional business model with the 5 development lines: Graphic, high-end scientific, mid-range scientific, student, and business.

They have covered most of them with the 50g, 17bii+, 35S, and now 20b.. the only remaining one is the High-end Scientific model. Perhaps we will hear about it at the HHC2008...barely 60 days to go!


#13

Quote:
Well put! I can see this coming out by April 2009. If you look at HP's traditional business model with the 5 development lines: Graphic, high-end scientific, mid-range scientific, student, and business.

Thank you, also for pointing out these 5 model lines. Where from is this information? For sake of clarity, can you place some model numbers in each such line? I must confess I did not notice line 2 in the last 10 to 15 years at all. More precisely, I must have missed the HP42s+ ;)

#14

what was the last high-end scientific non-graphing model?

I think that went extinct with the 42s.

I'm not sure they have had 5 lines going in the last 20 years. More likely FOUR lines rather than five.


#15

I first noticed this pattern when trying to find enough leather cases for my Clamshell/Voyager/Pioneer series. I chose Burgundy for the financial, Brown for high-end scientific, and Black for the others.

(incomplete)
Type CL Spice VGER Clam Pioneer Charmne. ACO
===================================================================
MS 35 33e 11c 28c 20s/32s/ii - 33s/35s
HS 45 33c/34c 15c 28s 27s/42s - ??
ST - 31e/32e 10c/16c 18c 21s/22s 38g 39/40g
BF 80/70 37e/38e/38c 12c 19b/ii 10b/14b/17b/ii - 12cp/17bii+
GR - - - - - 48s/x/g/x 49g/+/50g

Where:
MS= Mid Range Scientific
HS= High-End Scientific
ST= Student (Specaility Calculator)
BF=Business/Finance
GR=(Advanced) Graphing

CL= Classics
VGER= Voyager

Functions are "generally" traceable to the previous generation in the series.

Note: It is my opinion that the Graphic Calculators really started with the 41C series. While the 42S was marketed as a 15C upgrade, many of the features were reverse compatible with 41CV programming. Likewise, the 48S functions build on the 41cv+advanced module+XMEM+Connectivity idea that started with the 42S.

There may not be a reason to build an advanced scientific model when the 35S and 50G close the gaps with memory and connectivity, but for any current HP designer who is cognizant of the Corvallis Handheld legacy, there seems to be a piece missing.

There are more subtle differences between many of the models that make them hard to fit into 5 categories.. Looking chronologically, you can find marketing materials for many of the models that show the new 'replacement' models were aimed at satisfying certain loyal users. The most obvious are the 32s and 42s whose boxes bear explicit 11c and 15c upgrade markings.


#16

Allen, here's a link to Craig Finseth's HP Calculator Evolution Diagram that you might find useful:

http://www.finseth.com/hpdata/evol.php


Regards,


John

#17

For US$ 40.- this is a quiet impressive calculator even if the keyboard is not perfect. But in Europe the pricing will be more than twice as high!! (EUR 54,95 as announced on dynatech.de) This definitely sucks! Sorry for the strong language, but I really see no reason for this difference in prices. I expect the pricing in Switzerland will be even higher, as it is the case for the HP 35S. It might be cheaper to buy it the U.S. in spite of shipping cost and custom taxes...

Juergen

#18

Quote:
1) Log base 10 is present in the machine. Press Shift Math UP.

Ahh.. yes, I missed that in the menu..Thanks!

Quote:
2) Factorial returns the gamma function for non-integer arguments using the non-integer argument plus 1 as the input to the function. 0.5 ! returns gamma of 1.5.

I had assumed the gamma function was used for non-integers, alas I have no experience for the range 0<N<1 ( which is outside accepted range according to the manual which says 1<n<253)

Quote:
3) Given that the 20b is a business model, I'm not quite sure what other arrangement you would have liked for the x^2, SQRT, 1/x, etc., functions. :-)

For the functions that are commmon with the 17bii+, I see no reason to move them or to rearrange the [ ( ], [ ) ], and [ +/- ] keys. I think the common keys is one reason people will buy a used calculator when a newer one is cheaper and faster.

Quote:
4) It has also been a LONG time since an HP business model had permutations and combinations present.

Indeed, I'll add this to the list. Thanks.!

Quote:
5) It also has stats functions beyond the probability distributions that have not been on an HP before (?)... standard error of the mean and covariance.

I'm not there in the manual yet.. but will look for it. Again, Thanks for the feedback.

I am happy to review future calculators, but have only spent an hour or so with the 20b, while pre-viewers have had a month advantage on me.

Please note the updated keystrokes for putting ones name on the display. The number of [UP] keys necessary to enter the input screen is 4, not three as stated in the HP tech notes.

I definitely think this is an exciting summer, and am quite pleased with the 20b (keyboard notwithstanding)!!! Thanks for the comments!


#19

Allen,

you mention that the default mode is algebraic. After you reset to RPN, does it retain the mode on reboot or do you have to reset it every time?

Thx.


#20

And, remember, it has Chain logic (1 + 2 x 3 = 9) as well as algebraic logic (1 + 2 x 3 = 7).

Default is Chain, not algebraic.

#21

It stays in the mode you set.

The matter of not being set to RPN mode at the factory is obvious. HP needs to appeal to their bread & butter -- not their truffles & foie gras. :-)

#22

The use of the factorial function for the gamma of (x+1) has been around a while.

The 35s factorial function gives the same results as that of the 20b for non-integer arguments.

If you were to graph the results, it would be a smooth curve.

#23

Quite a few unused SMT pads there! Very interesting. I'd like to see where the traces go.


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