Search found 1610 matches

by Andy Rea
Wed Jan 26, 2011 4:43 pm
Forum: Hardware
Topic: New Hardware Projects
Replies: 88
Views: 43926

Re: New Hardware Projects

SirMorris, are you on about the video correction circuit ? if you are be sure to test it with 25thanni, i found that with my first version based around the LM1881 that the scroller at the bottom of the screen starts to output character data right after the hSync and was causing the display to go wob...
by Andy Rea
Tue Jan 25, 2011 11:27 pm
Forum: GAMES
Topic: While we are releasing games...
Replies: 5
Views: 6534

Re: While we are releasing games...

Of course, free for everybody to use as they please, shame i no longer have the Assembly listing for Tron trails, but the assembly listing is there for the lights out, maybe somebody would like to add the other 60 levels :lol: it's quite easy if you have a look at the assembly.

Regards Andy
by Andy Rea
Tue Jan 25, 2011 7:17 pm
Forum: Sinclair Misc
Topic: Egg on my face
Replies: 4
Views: 3988

Re: Egg on my face

Whoops :lol:

we all have bad days Rich, i appriciate the effort and time and resources you put in to keep these forums going i'm sure the others will say the same.

Regards Andy
by Andy Rea
Tue Jan 25, 2011 7:10 pm
Forum: GAMES
Topic: While we are releasing games...
Replies: 5
Views: 6534

While we are releasing games...

here are a couple i wrote way back in 2006 and 2007 Tron trails, race your 'light bike' which is a black blob :? around the screen trying to get your computer opponent to crash first ! written 2006 lightsout, conversion of tiger games classic lights out game, all custom levels, written nearly all in...
by Andy Rea
Sun Jan 23, 2011 3:11 pm
Forum: Hardware
Topic: i2c
Replies: 3
Views: 4509

Re: i2c

That looks like an interesting chip, looks easy enough to hang off the z80 bus and as you say takes the work out of having to write a 'bit banger' yourself, i'll be adding one of those to my shipping list :)

Thank you

Andy
by Andy Rea
Fri Jan 21, 2011 6:24 pm
Forum: SALES
Topic: Timex 16K ram pack on ebay
Replies: 2
Views: 5070

Timex 16K ram pack on ebay

http://cgi.ebay.co.uk/Sinclair-ZX81-TS- ... 2c5a2e98df

Nothing to do with me, but if any are collecting timex stuff :)

All the best Andy
by Andy Rea
Thu Jan 20, 2011 6:16 pm
Forum: Development
Topic: ZX81 Rom Routines
Replies: 6
Views: 7278

Re: ZX81 Rom Routines

Hi Tim, I have done a little bit of experimenting and have come up with the following. 0061 4082 01 00 00 PLOT LD BC,$0000 0062 4085 2A 30 40 LD HL,($4030) 0063 4088 E5 PUSH HL ;SAVE t-ADDR 0064 4089 3E 98 LD A,$98 ;AS LONG AS IT'S LESS THAN $9E SHOULD PLOT. 0065 408B 32 30 40 LD ($4030),A 0066 408E...
by Andy Rea
Wed Jan 19, 2011 11:54 pm
Forum: Hardware
Topic: i2c
Replies: 3
Views: 4509

i2c

Hi, I have read references to the i2c used by some on here, but can not find details of how to build such an interface, i should be able to code a 'bit basher' as long as i can get the hardware working, i want to interface an i2c RTC to my zx81, as part of my hard disk drive clock project, once ever...
by Andy Rea
Wed Jan 19, 2011 10:45 pm
Forum: Development
Topic: New game - "Laby"
Replies: 15
Views: 25408

Re: New game - "Laby"

Hi Bernd, Yes i can see how you are storing the mazes, so as you say not much if any to be saved there. only thing i can think it that you try to optimise the assembler more, i have never used 'C' to program zx81, does it compile to assembly listing or directly to binary ? if you get the intermediat...
by Andy Rea
Wed Jan 19, 2011 8:28 pm
Forum: Development
Topic: ZX81 Rom Routines
Replies: 6
Views: 7278

Re: ZX81 Rom Routines

for un-plotting try to make sure memory address $4030 holds the value $9E before calling the routine, any value lower than $9E and the plot/unplot routine will call plot in any case, also the value of A prior to the call $0BB2 has noo effect, A is loaded with the value $2B (43 in decimal) to check t...