HP67 PAUSE Card Load

[teenix]

Hi all,

Any HP-67 gurus out there that can confirm that a card placed in the card slot ready to auto load when a PAUSE instruction executes in a running program, will load the card and then start executing the new program from Step 1 of the program.

I am assuming a Merge PAUSE in the same situation will keep running the program from the next step after the pause.

cheers

Tony

[Thomas Okken]

Yes to both. And also note that when loading a program with MERGE, the RTN stack is preserved, and when loading a program without MERGE, it is not.

[[kby]]

(11-22-2020 06:22 PM)Thomas Okken Wrote:  Yes to both. And also note that when loading a program with MERGE, the RTN stack is preserved, and when loading a program without MERGE, it is not.

I found in a brief experiment on the 97 in both cases that it will start at the first step of the new card. I don’t have time right now to input my test program but will do so later.

This assumes that the card you refer to as waiting to be read is a program card, not a data card. Regardless of the program steps in the original program, reading a program card should overwrite the old program so there is no place to continue other than the first step of the new program, no?-kby

[Thomas Okken]

(11-22-2020 07:01 PM)[kby] Wrote:  Regardless of the program steps in the original program, reading a program card should overwrite the old program so there is no place to continue other than the first step of the new program, no?-kby

No. When a program is loaded with MERGE, it is loaded after the current line. So, from a program that uses the sequence MERGE PAUSE, the program is loaded after the PAUSE.

In both cases, execution continues at step 1 of the loaded program. The difference lies in where in program memory that program ends up.

It just occurred to me that there is another experiment I should do, namely, check what happens if MERGE is performed while there is a pending RTN to a location after the MERGE. A pending RTN to a location before the MERGE works as expected, but a location after the MERGE doesn't really make sense, so how is that handled?

UPDATE: There's no special handling for bogus RTN locations. So, if at the time of the MERGE, there is a pending RTN to somewhere after that MERGE, execution will still return to that location, even though it has been overwritten.

[teenix]

Thanks for the help :-)

This line in 67 manual Pg 294 didn't offer much insight, but the answers make sense.

"6. Execution will resume automatically when the card is read."

cheers

Tony

[[kby]]

I’ll have to read and fiddle around more later. While trying to do this on the 67 batteries went lie, then when plugged in looks like an ACT or ROM failure (turns on with all 0s and a sigh I’m the mantissa and exponent no decimal point and unresponsive). Somehow my 97s had a stick or misaligned card reader I’m trying to fix, my other 97 has a bad printer feed, which is not critical for this, but. The 67 would be the easiest for me to fiddle with this on. Much more familiar with -65 behavior than -67.-kby

[teenix]

(11-23-2020 12:45 AM)[kby] Wrote:  I’ll have to read and fiddle around more later. While trying to do this on the 67 batteries went lie, then when plugged in looks like an ACT or ROM failure (turns on with all 0s and a sigh I’m the mantissa and exponent no decimal point and unresponsive). Somehow my 97s had a stick or misaligned card reader I’m trying to fix, my other 97 has a bad printer feed, which is not critical for this, but. The 67 would be the easiest for me to fiddle with this on. Much more familiar with -65 behavior than -67.-kby

I hope not in your case, but faulty batteries/terminals and plugged into a charger can be a bad combination on the 67 and may result in damage like the "no batteries with charger" problem. I think external changing is the only safe option for this model and the Woodstocks these days.

cheers

Tony

[[kby]]

(11-23-2020 01:11 AM)teenix Wrote:  

(11-23-2020 12:45 AM)[kby] Wrote:  I’ll have to read and fiddle around more later. While trying to do this on the 67 batteries went lie, then when plugged in looks like an ACT or ROM failure (turns on with all 0s and a sigh I’m the mantissa and exponent no decimal point and unresponsive). Somehow my 97s had a stick or misaligned card reader I’m trying to fix, my other 97 has a bad printer feed, which is not critical for this, but. The 67 would be the easiest for me to fiddle with this on. Much more familiar with -65 behavior than -67.-kby

I hope not in your case, but faulty batteries/terminals and plugged into a charger can be a bad combination on the 67 and may result in damage like the "no batteries with charger" problem. I think external changing is the only safe option for this model and the Woodstocks these days.

cheers

Tony

As long as it’s the ACT and not one of the ROMs I’m OK. I can scrounge another ACT, if from no place else then one of the -67 boards I have with the buggy ROMs. Or if it’s a ROM but not one of the buggy ones, then I have those too, but I’ll need to figure out which are the problematic ROMs.

On the -67, though, I am a little surprised that it has the charger no batteries issue since even though internally it’s a Woodstock, it uses the Classic charger which is regulated DC, right? Isn’t it just like running a Classic off of AC only as the charge buckle essentially does that? The -97 is another matter, and should be subject to the Woodstock problem

[teenix]

(11-23-2020 05:44 AM)[kby] Wrote:  On the -67, though, I am a little surprised that it has the charger no batteries issue since even though internally it’s a Woodstock, it uses the Classic charger which is regulated DC, right? Isn’t it just like running a Classic off of AC only as the charge buckle essentially does that? The -97 is another matter, and should be subject to the Woodstock problem

Not really sure, but just going by HP-67 owners manual Page 27 and Page 312.

HP-97 Page 23 and on Page 232
"Whether you operate from battery power or from power supplied by the charger, the battery pack must always be in the calculator."

However, Section 2-41 of the 97 Service Manual says that the 97 can be operated without batteries, but won't work properly.

cheers

Tony