[vcf-midatlantic] Known-good IBM joystick?

Hagstrom, Paul hagstrom at bu.edu
Tue Jul 10 14:03:53 EDT 2018


Retrieve STICK(0) first.  STICK(0) will sample all the joystick values and return the x-coordinate of joystick A.  STICK(1) returns the y-coordinate of joystick A that it found last time STICK(0) was called.

https://archive.org/stream/IBMBASICAV1.10Manual/IBM%20BASICA%20v1.10%20Manual#page/n375/mode/2up

Also, are you sure the values go from 0-255 like they do on the Apple?  In particular, if it's only, say, returning 0-100, then it's never going to be more than 180, and it's likely to go the other way when in an auto-entered resting state.

 -Paul




> On Jul 10, 2018, at 1:34 PM, Evan Koblentz via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:
> 
> I know anyone can make mistakes, but .... I am VERY confident in my code this time around.  :)
> 
> Alas, I don't have the actual IBM code here at home.
> 
> The joystick routine in my (perfectly working) Applesoft code is:
> 
> --------------------------
> 
> 3000  REM NAVIGATION
> 3010 FB =  PDL (1):LR =  PDL (0):M = 0: REM  SET VARIABLES
> 3020  IF FB < 75 THEN M = 5
> 3030  IF FB > 180 THEN M = 10
> 3040  IF LR < 75 THEN M = 9
> 3050  IF LR > 180 THEN M = 6
> 3060  POKE L,M: REM  SEND COMMANDS
> 3070  IF M = 10 THEN  CALL  - 198: FOR W = 1 TO 500: NEXT W: REM BACKUP ALERT
> 3080  RETURN
> 
> --------------------------
> 
> I made two changes for the IBM side:
> 
> 3010 FB=STICK(1):LR=STICK(0):M=0: REM SET VARIABLES
> 
> 3060 OUT P,M: REM SEND COMMANDS
> 
> Both lines are correct. No room for gray area there.
> 
> I omitted line 3070 for now. It makes the backup beep when the robot goes in reverse. :)  I'll add an IBM version back in after I get the navigation working again.
> 
> I don't have time now to explain to everyone how the Lego system works, but anyone who's interested is welcome to examine the relevant pages of my under-construction web site about this subject. :)
> 
> http://www.snarc.net/mbts/applebasic.htm
> http://www.snarc.net/mbts/direct.htm
> 
> 



More information about the vcf-midatlantic mailing list