|Re: HP15C LE Pause Operation not as expected|
Message #12 Posted by Jeff O. on 3 Feb 2012, 8:31 a.m.,
in response to message #6 by Thomas Chrapkiewicz
This bug does not exist in the preproduction 15c+ machine (the prototypes from the HHC2010). (Has this been reported here?)
Yes, see this post for example.
Has anyone compared the advantages/disadvantages of the 15c+ code with the 15CLE code?
Perhaps it would be worth transplanting the 15c+ code to a 15CLE machine.(?)
The firmware that came on the 15C+ units presented to HHC 2010 attendees is dated 2009-08-03. While it may not exhibit the so-called PSE bug, there are issues with it, as follows:
At the conference, we were told (if I recall correctly) that integration was slow with 15C+. The sample program that was presented with the 15C+ included an integration. The documentation that I have from the meeting states that the program ran on the original 15C in 123 seconds and on the 15C+ in 7.5 seconds. I went ahead and entered the program onto machines running both the 2009-08-03 firmware and the 2011-04-15 firmware of the current production units. On the machine running the 2009-08-03 firmware, it indeed ran in 7 to 8 seconds. With the 2011-04-15 firmware, it ran in about 1.4 seconds, so I can confirm that integration was indeed slow with the 2009-08-03 firmware.
Also found at the conference was a bug in the display of program line numbers. For example, enter 62 steps in program memory, then go to step "000" and back-step. The program counter will show "05o", "05-", then "05r" before showing the correct "059" step number. If you enter 63 steps and back-step, it will start at "057", then "056", etc., all the way down to "000". Continuing to back-step shows step 999, 998 997, 996, 995 and 994 before cycling back to 057.
Like the 2011-04-15 firmware of the production units, the 2009-08-03 firmware does not like combinations and permutations in programs. Enter the following program from the 15c LE bug reports article:
Now enter a small number, 1, 2, 3, etc. and run the program. It will come back quickly with the expected answer of 56. Now enter a larger number, like 56, and run the program. The display will briefly show running once, then go blank. Despite the blank display, the program continues to run, executes the loops, and then stops. Now alter the program like this:
Note that I put the PSE in the wrong place if I want to see each iteration then stop. Enter a small number like 5 and run the program. It dutifully stops at each pause and displays 56. Then the display goes blank, but the program is still running. Wait a while and press a key to stop it, then recall register 0. It will have a large negative number in it, indicating that the calculator continued to run after counting down to zero. This is proper execution of the program as entered, except there was no running display to tell you that the calculator was still running to indicate that you made an error in the program. If you replace the Cy,x with Py,x, you get the same behavior. If replaced by another function, say y^x, it works fine. So using Cy,x or Py,x in a program blanks the display while the program is running. If you somehow got into an endless loop, you might think the calculator was off while it continued to run with a blank display.
Another anomaly is if you set flag 9, either manually or in a program. With proper operation, the display starts flashing when you set flag 9, and stops if you clear it with g-CF-9, or press the back-arrow key. This is what happens with the 2011-04-15 firmware. With the 2009-08-03 firmware, setting flag 9 causes the display to go blank. If you press a key, there is a momentary display, then it goes blank again. It appears that keystrokes and functions work normally, the display just blanks out after each key-press. Normal display is returned by pressing the back-arrow key, or g-CF-9, i.e. the standard way to clear flag 9.
The above behavior also occurs for overflow conditions which would normally cause a flashing display.
Finally, the 2009-08-03 firmware also exhibits items 3, 4, 5, 6 and 10 from the 15c LE Bug Report Article.
Based on the above, I do not consider the 2009-08-03 firmware to necessarily be a good alternative to the 2011-04-15 firmware.
Edited: 3 Feb 2012, 1:23 p.m. after one or more responses were posted