DM-xxCC Default Display Values



#2

Michael has really improved the look of his web site at http://www.rpn-calc.ch/. The home page now features a carrousel of all five calculator models.

Mindlessly spinning the calculators, I started wondering why he chose the various default display values for each model:

DM-10CC = 1.7321
Easy, 3 SQRT

DM-11CC = 1.4142
Again easy, 2 SQRT

DM-12CC = 1.55
The best I that I can come up with is: 111 LN LN

DM-15CC = 1.6180
Pure gold, 5 SQRT 1 + 2 /

DM-16CC = AA55 H
Again, no idea:
BIN 1010101 Enter Enter 1001 RLn + HEX
or
HEX 55 Enter Enter 9 RLn +

Does anyone have a better solution for the DM-12CC or DM-16CC? Maybe Michael could give us the real answers.

Mark Hardman


#3

About the "AA55": don't think too much about mathematics there, remember it's a programmers' calculator. And "AA" and "55" are two bytes often used for memory testing, as they have a peculiar bit pattern - AA is 10101010 and 55 is 01010101. So it might just be a tribute to old-style computer programming, which is what the 16C was for.


#4

It goes back even further than that. In the old Teletype days (Western Union Telex et al), they used to send a line of "RYRYRYRYRYRYRY"... in order to "exercise" the send and receive contacts. These machines use the old 5-level (5-bit) "Baudot" code. R and Y are the TTY equivalent of 0xAA55 for memory tests --- their bit patters are 01010 and 10101 (but I don't remember offhand which is which).

They especially look nice punched into paper tape!

|  o   o   o   o   o   o   o   o  o

| o o o o o o o o

| o o o o o o o o o

| o o o o o o o o

| o o o o o o o o o

Dale, W8ABZ

(Don't ask how many Teletype (R) Model 19ASR, 28ASR and 32ASR machines I fixed back in the radio club in college days....)

#5

I wonder what the keys of the ones with titanium housing will be like!


Possibly Related Threads...
Thread Author Replies Views Last Post
  [HP Prime] Constants Library Values Timothy Roche 24 2,202 11-02-2013, 04:17 PM
Last Post: Les Koller
  HP 35s - multiple program input values? Arno 3 525 04-29-2013, 11:27 AM
Last Post: Gerson W. Barbosa
  DM-1x Silver vs. DM-1xCC Aluminum quality? bhtooefr 11 1,007 04-14-2013, 07:08 PM
Last Post: bhtooefr
  [wp34s] Alternative MIO (allows calculations when entering element values) David Maier 1 338 02-03-2013, 02:51 PM
Last Post: Marcus von Cube, Germany
  Flashing the DM-15CC Geoff Quickfall 11 901 01-14-2013, 05:18 AM
Last Post: Mike (Stgt)
  Review of the DM-16CC hpnut 1 358 01-04-2013, 04:21 PM
Last Post: Guido (Canada)
  Default angle mode Eric Smith 71 3,425 12-06-2012, 01:19 AM
Last Post: Eddie W. Shore
  DM 15CC silver edition arrived! Hans Holzach 10 1,064 12-05-2012, 01:40 AM
Last Post: Juergen Keller
  dm-15cc battery life David Griffith 7 754 12-04-2012, 10:07 PM
Last Post: Walter B
  Can the display for a HP32Sii be replaced with the display from another model? Bruce Larrabee 8 935 10-10-2012, 10:05 PM
Last Post: Luiz C. Vieira (Brazil)

Forum Jump: