WP34s flashing procedure

[John Galt]

I believe removing the paper clip in Step 3 won't result in erasure, but as rprosperi wrote other people will enthusiastically correct me.

This is what I do.

1. Start with the calculator OFF
2. Connect Erase (J36, lower left) to Vcc (J31, upper right) and leave it connected.
3. Press ON. Calculator will turn on.
4. Press RESET. Calculator will turn off.
5. Disconnect the Erase connection.
6. Press ON. Calc will look dead but it is really ON.

You are now ready to flash with MySamBa.

When the file transfer is complete, press RESET to turn the calculator off.

I really don't understand what Marcus means when describing a "strobe" function; it's probably attributable to my understanding of the terminology or regional English differences. If you follow the above procedure, there is no concern about "contact bounce" etc, no more so than with contact bounce under any other operation, normal or otherwise. If you repeatedly press ON in Step 3 (or 6), or if you repeatedly press RESET in Step 4, or if those repetitions are due to "contact bounce" or some other anomaly, no harm will result.

[MarkHaysHarris777]

(02-27-2015 08:05 PM)John Galt Wrote:  I really don't understand what Marcus means when describing a "strobe" function; it's probably attributable to my understanding of the terminology or regional English differences.

With all due respect, the paper clip in the back of the unit is doable (I did it even) but its dangerous; words to the wise.

First let me tell you what I don't mean, regarding strobe. Strobe sometimes is used to refer to a signal that is momentarily received (by several gates) in a multiplexing environment to 'select' (or write enable) the particular chips being 'strobed' (because *all* the chips are on the same bus or parallel com lattice and some way is needed to tell the chips which 'one' is being written to now. ( I do not mean strobe in that sense, obviously, I think).

When I refer to strobe I mean a 'clean' leading edge pulse (rising from low to high over time, usually very shot time) that is used to communicate an 'ON' condition or some other input to a MOS or CMOS input (but can also be TTL). Versus a trailing edge pulse (also clean) running from high to low over time (again short time) normally referred to as a ground shot, in TTL logic.

When I speak of strobe I mean a very clean noiseless high signal that is held for some time and then released, as in the 'erase' strobe of the WP34s.

This is as 'apposed to' a noisy (non contact bounce conditioned ) electrical push button switch (finger actuated) which creates for the MOS or CMOS input what amounts to an electrical train wreck on the capacitive input; the worst for the condition is a damaged MOS gate, with the probable resulting condition being erratic behavior or non behavior. To put it simply a bare metal contact switch should (bold here, NEVER) not be used to signal MOS or CMOS gates. The 20b-30b flash cable (the one commercially produced for HP, I'm not knocking anyone present in the DIY community) is an over-simplified electrical possibility which is going to be unreliable and which may do damage, IMHO. But hey, HP was trying to provide to the community a least expensive 'probably-will-work-most-of-the-time' setup (most people are not going to invest in a JTAG development system, nor are they likely to build their own flash-box--probably not.

The preceding discussion does not change the harsh reality that (although the micro-controller is fairly robust) there isn't much protection on the Tx Rx pins, and the commercial flash cable does really nothing to help the user understand what is happening in the process (it either works or it does not work, and if it does not work, oh well---try again).

This article about contact debounce conditioning is an excellent read on debouncing MOS and CMOS inputs, the various hardware options for same, and why its important.

Cheers,
marcus

[Dieter]

(02-27-2015 08:05 PM)John Galt Wrote:  This is what I do.

1. Start with the calculator OFF
2. Connect Erase (J36, lower left) to Vcc (J31, upper right) and leave it connected.
3. Press ON. Calculator will turn on.
4. Press RESET. Calculator will turn off.
5. Disconnect the Erase connection.
6. Press ON. Calc will look dead but it is really ON.

You are now ready to flash with MySamBa.

When the file transfer is complete, press RESET to turn the calculator off.

It worked! I just flashed a new 20b to become a 34s. :-)

Just to be sure: is it possible to use the standard update procedure (ON+D D, ON+S S) to turn a 34s into a 31s and vice versa? I am asking because I wonder what happens to the saved settings that are usually restored after an update. The backup included all programs and data registers, but all this (resp. only a few data registers) is not supported by the 31s.

BTW1: I do not see a significant difference between the 30b and 20b displays.
BTW2: Yes, IMHO the 30b keyboard is by far the better one.

Dieter

[Marcus von Cube]

(03-01-2015 04:26 PM)Dieter Wrote:  Just to be sure: is it possible to use the standard update procedure (ON+D D, ON+S S) to turn a 34s into a 31s and vice versa? I am asking because I wonder what happens to the saved settings that are usually restored after an update. The backup included all programs and data registers, but all this (resp. only a few data registers) is not supported by the 31s.

I'm pretty sure that the image in flash will not be recognized as valid by the "alien" firmware. So it will will most probably come up with "erased" instead of "restored".

[Dieter]

(03-01-2015 08:38 PM)Marcus von Cube Wrote:  I'm pretty sure that the image in flash will not be recognized as valid by the "alien" firmware. So it will will most probably come up with "erased" instead of "restored".

That's fine by me. But do you think otherwise everything should work, i.e. a 34s that is updated with 31s firmware – or a 31s that is updated with 34s firmware – correctly comes up as the respective "new" calculator type?

Dieter

[Marcus von Cube]

(03-01-2015 09:15 PM)Dieter Wrote:  That's fine by me. But do you think otherwise everything should work, i.e. a 34s that is updated with 31s firmware – or a 31s that is updated with 34s firmware – correctly comes up as the respective "new" calculator type?

Yes it will. If you want to make sure none of the old data remains in flash, just repeat the ERASE procedure. From my point of view this will not be necessary but if it makes you sleep better do it!

[Dieter]

(03-01-2015 09:28 PM)Marcus von Cube Wrote:  If you want to make sure none of the old data remains in flash, just repeat the ERASE procedure. From my point of view this will not be necessary but if it makes you sleep better do it!

OK, so I did it that way. Say hello to my first hardware 31s. ;-)

Dieter