Search found 431 matches

by at67
Today, 02:46
Forum: Support
Topic: Nonfunctional Gigatron.
Replies: 10
Views: 118

Re: Nonfunctional Gigatron.

Dodgy Arduino HW/SW CRO's can be super misleading on digital circuits in the MHz range, they are usually fine for Audio and KHz, but I wouldn't trust what you are displaying. e.g. Are the units per division correct? If they are then those signals are rubbish, also the signal with ringing/undersampli...
by at67
Today, 02:35
Forum: Hardware and software hacking
Topic: gtBASIC
Replies: 178
Views: 40300

Re: gtBASIC

This was a design choice, I coded that particular function in the runtime so that if there are any non-alpha chars, (apart from the -ve symbol), in the string then it would return 0. This function would be 2x or maybe even 3x bigger to handle all cases properly and I deemed it not worth the waste of...
by at67
24 Nov 2021, 12:51
Forum: Support
Topic: Nonfunctional Gigatron.
Replies: 10
Views: 118

Re: Nonfunctional Gigatron.

It's painful but have you checked for shorts/open circuits on every chip using a multi-meter whilst the board is not powered? Have you measured the voltage across a random selection of the TTL chips? (VCC should be 4.75v to 5.25v) It's hard to tell, but it looks like you have used HCT as your TTL fa...
by at67
18 Nov 2021, 10:22
Forum: Hardware and software hacking
Topic: Can I build with HC rather than HCT series ICs ?
Replies: 5
Views: 164

Re: Can I build with HC rather than HCT series ICs ?

In theory if you replace ALL the chips with pin equivalent HC versions you should get better noise immunity. The problem is I don't think you can replace every chip with an HC equivalent and as soon as you start mixing TTL logic levels with HC logic levels you are invariably going to face problems. ...
by at67
17 Nov 2021, 06:40
Forum: Hardware and software hacking
Topic: gtBASIC
Replies: 178
Views: 40300

Re: gtBASIC

Replace that line with this for now:

Code: Select all

IF ((A=15) AND (O<>20) AND (O<>1)) OR ((A=29) AND (O<>16)) OR O>C3 THEN
by at67
17 Nov 2021, 06:13
Forum: Hardware and software hacking
Topic: gtBASIC
Replies: 178
Views: 40300

Re: gtBASIC

wbushby wrote: 17 Nov 2021, 02:09 I have found issues with comparative logic in IF..THEN statements

IF (A=15 AND O<>20 AND O<>1) OR (A=29 AND O<>16) OR O>C3 THEN...

This gives error 'syntax error in number literal'
Thanks I'll check this line out and get back to you.
by at67
17 Nov 2021, 06:13
Forum: Hardware and software hacking
Topic: gtBASIC
Replies: 178
Views: 40300

Re: gtBASIC

wbushby wrote: 15 Nov 2021, 20:34 Is command INT(x) implemented in this version of basic ?
This function converts floats to ints? If so, there are no floats in gtBASIC, yet...
by at67
17 Nov 2021, 06:08
Forum: Hardware and software hacking
Topic: 6Bit audio:
Replies: 26
Views: 7769

Re: 6Bit audio:

axelb wrote: 16 Nov 2021, 07:37 This is a breadboard-tested solution for the 8 bit audio.
That looks great, good job designing and testing it.
by at67
10 Nov 2021, 06:15
Forum: Hardware and software hacking
Topic: MINT - a minimal interpreted language
Replies: 3
Views: 121

Re: MINT - a minimal interpreted language

This looks very cool, like a modern version of CHIP8, that kind of ethos?
by at67
08 Nov 2021, 15:42
Forum: Hardware and software hacking
Topic: Implementing a faster multiplication routine
Replies: 20
Views: 2695

Re: Implementing a faster multiplication routine

Is my code uniformly faster across the board, or am I making big gains on some "expensive" pixels, and doing less well on other, "cheaper" pixels. After all, Marcel's code would be very fast when one value is zero! Does that happen? Does that happen often? Marcel's code will onl...