Search found 107 matches

by tzok
Mon Jul 15, 2019 1:39 pm
Forum: 8 BIT CORNER
Topic: 27C400/27C800 EPROM emulator
Replies: 16
Views: 465

Re: 27C400/27C800 EPROM emulator

What is the access time?
by tzok
Sun Jul 14, 2019 4:40 pm
Forum: HARDWARE ISSUES
Topic: Plastic yellowing: Light + heat?
Replies: 10
Views: 301

Re: Plastic yellowing: Light + heat?

I think the yellowing may also have something to do with using gas stoves/cookers in house where the Atari is/was kept.
by tzok
Sat Jul 13, 2019 9:25 pm
Forum: CHAT FORUM
Topic: 520STFM - TOS upgrade confusion
Replies: 8
Views: 202

Re: 520STFM - TOS upgrade confusion

You may look for 27C1000 (NOT 010 nor 1001) EEPROMs, but they are likely to be 200ns ones, so on the very border line of the acceptable latency for a stock 8MHz ST. They are 32 pins, but the "excessive" pins can be tied together and hooked to VCC (except \OE which should be tied to GND). You may als...
by tzok
Wed Jun 26, 2019 8:51 pm
Forum: SOFTWARE PROGRAMMING & DISCUSSION
Topic: change a bit in a variable ?
Replies: 6
Views: 199

Re: change a bit in a variable ?

It's pretty common in C... Set bit 3 (0 based index, so bit 3 is 4th bit): a|=(1<<3) Clear bit 3: a&=~(1<<3) << - shift left | - bitwise OR & - bitwise AND ~ - bitwise NOT Unfortunately Spectrum BASIC doesn't have bitwise operators, it only has logical ones :( I'm unsure if in HiSoft BASIC it is any...
by tzok
Wed Jun 26, 2019 2:29 pm
Forum: CHAT FORUM
Topic: Floppy corrupted when used on ST and PC won't read it ?
Replies: 18
Views: 351

Re: Floppy corrupted when used on ST and PC won't read it ?

So exactly opposite to my issue, but somehow expected - I was using a true DD drive in Atari and a DD formatted HD diskette together with a HD drive in PC. It is not as bad as with 5,25" disks, but HD drives dislike DD disks and opposite way around too. It works when formatted, saved and read in the...
by tzok
Tue Jun 25, 2019 11:12 pm
Forum: CHAT FORUM
Topic: Floppy corrupted when used on ST and PC won't read it ?
Replies: 18
Views: 351

Re: Floppy corrupted when used on ST and PC won't read it ?

Was it a true DD floppy or a HD floppy formatted to 720kB? With the latter ones, I had the same problem.
by tzok
Sat Jun 15, 2019 9:55 pm
Forum: ROM UPGRADES
Topic: MASK AND ROM PINOUTS EXPLAINED
Replies: 2
Views: 874

Re: MASK AND ROM PINOUTS EXPLAINED

Actually, there existed a 1Mbit non-JEDEC compatible EPROMs, which had the same A16 and /OE pin locations as MASK-ROMs, these were 27C1000 and 27C301. /CE pin location (22) is the same with all 27C1001/010/1000/301 and the MASK-ROM (you are showing pin numbers for 28 pin 256kb MASK-ROM)... or maybe ...
by tzok
Fri Jun 07, 2019 9:26 pm
Forum: HARDWARE ISSUES
Topic: Bad resistor?
Replies: 5
Views: 200

Re: Bad resistor?

These are not even resistors, but just a fancy jumper wires... apparently someone moved them from one position to another from the top (without removing the board from bottom case).
by tzok
Fri Jun 07, 2019 10:55 am
Forum: STFM
Topic: C070789-001 REV .D
Replies: 2
Views: 1955

Re: C070789-001 REV .D

Yet another C070789-001 REV .D:
C070789-001_REV.D.jpg
C070789-001_REV.D.jpg (544.11 KiB) Viewed 307 times
by tzok
Mon Jun 03, 2019 8:48 pm
Forum: HARDWARE DISCUSSIONS
Topic: Si5351A clock generator - any good for a booster?
Replies: 2
Views: 191

Si5351A clock generator - any good for a booster?

I have recently found a very interesting chip called Si5351A. It is a 3 channel clock generator (8kHz - 160MHz). All 3 clocks can be phase locked. Chip is programmable by the I2C bus. It is available as an breakout board from Adafruit, or from Aliexpress. Have anyone considered using it for an ST bo...