Search found 5975 matches

by exxos
Tue Jun 18, 2019 10:21 pm
Forum: ST 16MHz V2.X SERIES BOOSTERS
Topic: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)
Replies: 438
Views: 37282

Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

I think I have 2.2K resistors on this motherboard (I put them in sockets thankfully so can change them easy)... I mean 2.2K with 23 address lines , 16 datalines.. 39 pins.. 2.2K @ 5V = 0.0023A x 39 = 0.0897A. So with some other pins might as well round up to 100mA. 0.1A x 5v = 0.5watts. But of cours...
by exxos
Tue Jun 18, 2019 10:20 pm
Forum: ST 16MHz V2.X SERIES BOOSTERS
Topic: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)
Replies: 438
Views: 37282

Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

PhilC wrote:
Tue Jun 18, 2019 10:07 pm
Sorry, I've forgotten by what was the original speed of the CPU but regardless of speed, it's an achievement to make any stable kind of increase on a chip as old as a 68000.
Original was 8MHz... The SEC has pretty much always run at 50MHz. The SEC itself says 20MHz on it.
by exxos
Tue Jun 18, 2019 9:56 pm
Forum: MEMBER BLOGS
Topic: exxos blog - random goings on
Replies: 296
Views: 8330

Re: exxos blog - random goings on

I keep thinking about a alt-ram card.. I did add it to a SEC design, but each time I do a new board, I would have to solder more stuff , larger boards, more parts.. it just gets annoying so alt-ram never gets done. I just un-forgot I designed this a while back... fr.jpg The header would be to branch...
by exxos
Tue Jun 18, 2019 9:07 pm
Forum: ST 16MHz V2.X SERIES BOOSTERS
Topic: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)
Replies: 438
Views: 37282

Re: V2.5 BOOSTER CURRENT PROTOTYPE STATUS (SEC BOOSTER)

I have been running the SEC at 50MHz as much as possible the past days.. it seems to get around 25 passes then 2 bombs to desktop. I've repeated this a few times now. I think the SEC is overheating after a while. Oddly the 50MHz osc is getting rather hot as well. So earlier I put in a 40MHz osc (doe...
by exxos
Tue Jun 18, 2019 6:05 pm
Forum: MEMBER BLOGS
Topic: exxos blog - random goings on
Replies: 296
Views: 8330

Re: exxos blog - random goings on

V3 PCB. Pots gone, resistors added. Also had to fix the audio connector holes (tiny bit to small :roll: )

v3.png
v3.png (21.04 KiB) Viewed 30 times
by exxos
Tue Jun 18, 2019 6:03 pm
Forum: MEMBER BLOGS
Topic: exxos blog - random goings on
Replies: 296
Views: 8330

Re: exxos blog - random goings on

PhilC wrote:
Tue Jun 18, 2019 5:50 pm
And theres always the brightness adjustment on the monitor which is what I used when coming up with the values I sent you.
Yeah, I've got mine at 100% and its fine, but I still think it should be brighter, but could just be my crappy monitor.
by exxos
Tue Jun 18, 2019 5:48 pm
Forum: MEMBER BLOGS
Topic: exxos blog - random goings on
Replies: 296
Views: 8330

Re: exxos blog - random goings on

I've been experimenting with resistor values. Works out at like 9.5K, 400R.... or as in now, 33R 55R. Odd how the ratio changes :shrug: In anycase, the lower resistor values seem to give a cleaner "white" colour, so I am going to stick with those. I tried 68R and while the colours are brighter, it s...
by exxos
Tue Jun 18, 2019 3:46 pm
Forum: MEMBER BLOGS
Topic: exxos blog - random goings on
Replies: 296
Views: 8330

Re: exxos blog - random goings on

Getting better :)

Likely will remove the pots and used fixed resistors on the next version.

IMG_4382.JPG
IMG_4382.JPG (221.57 KiB) Viewed 46 times
IMG_4385.JPG
IMG_4385.JPG (163.57 KiB) Viewed 46 times
by exxos
Tue Jun 18, 2019 3:17 pm
Forum: MEMBER BLOGS
Topic: exxos blog - random goings on
Replies: 296
Views: 8330

Re: exxos blog - random goings on

Version 2 cooking :)

IMG_4381.JPG
IMG_4381.JPG (102.57 KiB) Viewed 51 times
by exxos
Tue Jun 18, 2019 8:55 am
Forum: ST 16MHz V2.X SERIES BOOSTERS
Topic: SEC REV SEC1_F3_2019 BETA FITTING INSTRUCTIONS
Replies: 3
Views: 56

Re: SEC REV SEC1_F3_2019 BETA FITTING INSTRUCTIONS

PhilC wrote:
Tue Jun 18, 2019 8:51 am
Can this be run without the Rom board but with slower Rom speeds?
Nope. ROM is decoded internally and run at high speed all the time, so the ROM board has to keep up.