Pre Release HP01 Running
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07-17-2016, 03:09 PM
Post: #21
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RE: Pre Release HP01 Running
(07-17-2016 11:09 AM)fhub Wrote:(07-17-2016 10:44 AM)teenix Wrote: 1) If you look in the menu you can see an option [Fine tune timer] This will adjust the timer for the processor execution loop and therefore the time updates. A bit like using the crystal trimmer on the watch circuit board. It will never be perfect, but neither was the actual watch. The time will always drift slightly. It will sync to the PC time on start up. This is a pre-release watch/calculator, not what was made available to the public as far as I know. The engineers of the day obviously saw the same problem and made some changes before presenting it for sale. Looking at the code as it executes, the keys don't do anything that I can see unless they are pressed directly after entering valid time/alarm values and set the AM/PM display indicator if in 12 hour mode. Status bit 1 is the flag for 12/24 hour mode. The A register data changes, but the display change shouldn't have occurred, so I have modified the way the code interacts with the "hardware" but will test further before updating. I cannot even say for sure what frequency the internal chips operate at because even though I looked over the logic diagrams that are in the patent document, (and there are lots) the circuitry in that area is a bit vague, and the only text reference I could find was "some other frequency...". Therefore, I have assumed that the 38.4KHz from the crystal is multiplied to a similar value as the Classic chipsets run on otherwise the calculator would be painfully slow to use. cheers Tony |
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