HP 29E IR GPS What????

[Dieter]

(05-25-2017 04:47 PM)PANAMATIK Wrote:  Yes. But Geoff should use f STO 1 and RCL 1 in the program instead, then R0 is still free to use as index register.

Geoff does not want to use any indirect register calls, it's me who suggested this way of extending the number of possible locations.

(05-25-2017 04:47 PM)PANAMATIK Wrote:  

(05-25-2017 03:04 PM)Dieter Wrote:  Any manual STO 0 during a regular calculation will stop the permanent update of this register.

No, this is true only when you are in GPS menu, not during regular calculation mode.
(...)
...your temporary value will be overwritten every second.

OK. Now please take a look at the second program version I suggested earlier in this thread:

Code:

01  LBL 0
02  RCL 0
03  X<>Y
03  STO 0
04  R↓
05  RCL i
06  +
..  ...

Here R0 is recalled, then an index number (1, 2, 3, ...) is stored there and the indexed register containing the timezone is recalled and added. This should take not more than about 0,1...0,2 seconds. Would this mean that the proposed program should work in, say, 4 out of 5 cases, but sometimes the GPS data update happens during these first steps before the RCL i, thus overwrites R0 so that RCL i recalls the wrong register?

Anyway, according to the above information this version should work once the GPS time is assigned to R 1:

Code:

01  LBL 0
02  STO 0  ; store index
03  ISZ    ; increment index to get register number for timezone
04  RCL 1  ; recall GPS time
05  RCL i  ; add local timezone
06  +
07  2
08  4
09  X<>Y
10  X<0?
11  +
12  2
13  4
14  X>Y?
15  CLX
16  –
17  RTN

This version uses R0 as index register while R1 holds the current GPS time (f STO 1). The timezone table is stored in R2 and up, so timezone no. (i) is returned by RCL (i+1). That's why I'd prefer GPS data to be stored in higher registers so that R1...R14 could be used for the timezone table.

(05-25-2017 04:47 PM)PANAMATIK Wrote:  

(05-25-2017 03:04 PM)Dieter Wrote:  Is there a chance that a later 29C GPS version may use more than just R 0 ... R 7?

This would be required only if you want to use all eight GPS values (UTC time, latitude, longitude, Speed, Heading, Elevation, doHP and No of Satellites) to be dynamically updated. But I don't think you need all of them. At least the HP-29E could be extended to use also registers 8-9 in a later version.

If would be a nice feature even if you only need one or two of the GPS values because it may free up the lower registers for general use. So an f STO ,5 would leave R 0...14 unchanged.

Dieter