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View Full Version : Fun with Harprit's book...



rohorn
11-21-2010, 07:30 AM
New at all this and have a need to learn it - so I got Harprit's book a few months ago at the local bookstore. It is even more educational now that I have the hardware!

Spent the last few evenings trying to get the display working with the "LCDminimal" program in Ch.14. All I got was 1 row of faint black squares. I was wondering if the display was bad, so I tried a display demo from the Object Exchange - now I have TWO rows of solid black squares - and faint readouts if the LCD is held at funny angles! Turns out that the contrast pin didn't like being grounded after all - replaced the jumper with a 2K resistor and it worked perfectly. But at least I got to see how the Object Exchange works - and how OBJ works in Prop Tool - that was neat!

Went back to "LCDminimal", compared it to the LCD data sheet, learned a lot, accomplished nothing, wondered why the display demo readout would still be on the display even though "LCDminimal" was uploaded, which didn't make sense. Checked the schematic against the program - and there it was - the "enable" and "write" display pins are assigned the wrong pins in the program (or the schematic is wrong).

And that has resulted in a good evening - I learned something, got results, and nothing caught fire. I'm looking forwards to finishing this book with more of that.

John Abshier
11-21-2010, 05:36 PM
This book has lots of errors. I remember reading that he has a web site with corrections.

Programming & Customizing the Multicore Propeller Microcontroller: Official Guide is a much better book.

John Abshier

Invent-O-Doc
11-21-2010, 05:53 PM
Harpit's book is an interesting and different approach with novel projects, though I agree that the Official guide is a better book, especially for learning purposes. The only part that is hard is that one of the chapter authors uses atypical timings (with a 10MHz crystal) and nothing works until you notice that.

prof_braino
11-21-2010, 06:30 PM
New at all this and .....
replaced the jumper with a 2K resistor and it worked perfectly. But at least I got to see how the Object Exchange works - and how OBJ works in Prop Tool - that was neat!

And that has resulted in a good evening .... and nothing caught fire.

Cool Beans!

Are you using this book along with or instead of the regular propeller manual?