Strange questions
ZXNet echo conference «real.speccy»
I’m thinking of connecting a flash to the Spectrum, but I ran into the following problem:
1. You need to somehow forcibly disable the BASIC ROM and connect TR-DOS.
2. And you need to manipulate the A16 signal.
3. And you also need to somehow make CS for microcircuits so that it works both for reading and
writing.
Point 1 is done only in KAY or SCORPION, and in different ways
nothing has been done on the Pentagon :-( What can we come up with here?
Point 2 can very much depend on point 1, probably just
a port into which you can write.
Point 3 causes some difficulties... For example, on a scorion or
KAY, you need to mix the signals A14, A15 and BLK (aka CSDCCE) on the logic I element.
And what can happen on all sorts of Pentagons of various modifications or
computers where instead of one ROM there are 2,3,4 or more microcircuits?
For example, TR-DOS controllers with their own ROM are common, the only thing that is clear
is that it is all replaced by one 28F0001BX... %-(
Finally, does anyone here want to replace the ROM with a flash drive? And don’t suffer
then with ROMs, numerous versions firmware and a bunch of glitches in them
- I took and programmed what I needed. Moreover, even in 128kb you can
in addition to the basics, put a couple of necessary programs and a normal bootloader
from disks/screws, test the computer... 100,000 cycles will be enough for the rest of the life
of this spectrum.
Even inScorpio with GMX has it, but the mythical Pentagon-2 does not :-(
Kirill Frolov. [ZX]
Somehow Kirill Frolov tapped on the keyboard to All:
KF> Finally, does anyone here want to replace the ROM with a flash drive? And then they don’t have to suffer
KF> with ROMs, numerous versions of firmware and a bunch of glitches in them
KF> - they took it and programmed what they needed. Moreover, even in 128kb you can
KF> in addition to the basics, place a couple of necessary programs and a normal loader
KF> from disks/screws, test the computer... 100,000 cycles will be enough until the end of the life
KF> of this spectrum.
1. How much does a flash drive cost?
2. What is the marking? is it suitable?
3.What signals does it have?
4.How to prohibit/allow writing to it?
5.Is there protection against accidental writing?
6.In general, the principle of programming?
7.A specific circuit plz...
ugh! In short, you can come up with a dozen more questions...
KF> Kirill Frolov.
C ya in nE>
with this:
KF> I’m thinking of connecting a flash to the Spectrum and ran into the following problem:
KF> 1. You need to somehow forcibly disable the BASIC ROM and connect
KF> TR-DOS.
I at one time I threw my own development - a ROM emulator. The same thing,
only SRAM 2x62256 is connected. I think it’s enough to just replace them with
FLASH.
All the best, Pavel Fedin.
KF>> then they suffer with ROMs, numerous firmware versions and
OG> 1. How much does a flash drive cost?
$3 or less if you tear it out of a pussy.
OG> 2. Which marking is suitable?
28F001BX-B or -T. With the letter B it’s wrong, their boot block starts with 0, but I haven’t seen them
. And with the letter T, the boot block starts at 1E000, you need to invert 3
signals.
OG> 3. What signals does it have?
I don’t understand. TTL, the pins are the same as the ROM, only 32 pins.
Address, data, power, general, OE, CS, WR, RP, VPP.
RP -- reset or +12V is supplied there at the time of writing/erasing the boot block.
VPP -- you need +12V if you want to write/erase.
OG> 4. How to disable/enable it recording?
With a jumper.
OG> 5. Is there protection against accidental recording?
There is a boot block. Unlike other blocks, its erasing or writing
is only possible when +12V is supplied to the RP. Those. if the program writes the main
block, it cannot spoil the boot block, you can put another
jumper to allow writing to the boot block.
OG> 6. In general, the principle of programming?
There is an automatic machine built into the chip that does this.
Controlled by sending to the command register commands and data, feedback
through the status register.
OG> 7. A specific circuit plz...
I'm thinking about it. I need to get 2 bits somewhere, I can’t find where. :-(
Kirill Frolov. [ZX]
KF> TR-DOS. 2. And you need to manipulate signal A16. Advertisement Output to A14..A17 ROM.
You attach the OE signal to the port, so that when resetting the output is disabled.
Resistors set the output to +5 volts and at start the highest bank is turned on.
Input addresses and data are attached to D0..D5, write signal to the port control
ROM addresses.
The startup program writes the required values into the registers and submits
permission to the OE. After that, you work and connect instead of BASIC48/128,
TR-DOS, EXPANSION whatever ROM pages you want.
For the third point, you cut off the /RD signal from the ROM decoding, send
it to the OE ROM. The decryption signal is on the CS, the recording signal on the ROM is /WR through an inhibiting register, so that all sorts of crooked BASICS do not ruin the flash drive.
And the last thing. In the older boot-block page, in case the computer crashes while the ROM is being flashed, this program should allow you to load the firmware from the drive and flash it.
By the way, flash drives have such a thing as write protection in the boot-block.
For example, 28F001 has older 16 kilobytes are sewn up only when a voltage of 12 volts is applied to the 30th leg, and not just to the 1st.
Wow!The Protoss are attacking my Zerlings! It's time to get going. Ivan.
- Divorce the scheme, big and small... [Sprinter-II] [Forth-CPU] [ZX]
... ivan...@mail.ru * http://st-rektal.chat.ru * http://www.atlant.ru/peters
04 Jan 00 15:21, Ivan Mak wrote to Kirill Frolov:
IM> For the third point, you cut off the /RD signal from the ROM decoding,
IM> and feed it to the OE ROM. The decoding signal is on the CS, the writing signal to the ROM is
IM> /WR through a prohibiting register, so that all sorts of crooked BASICS don’t ruin the flash drive
IM>.
What for? If they ruin it, you can sew it up again. Yes, and they won’t ruin it, before
they themselves will freeze, switch something...
IM> such a thing as write protection in boot-block. For example, in 28F001 the older
IM> 16 kilobytes are sewn up only when a voltage of 12 volts is applied to the 30th
IM> leg, and not just to the 1st.
Tell me then, you can apply +12 there from the jumper or as
on a piece of paper it is written only at the moment write/erase ?
┌───┐
RES X───────┤1 o──────┬───────────────> RP# (30 pin)
one time │ЛH3│ │
already inverted └───┘ ┌┴┐
rovan │ │
│ │
└┬┘
│
+ +12V jumper.
Kirill Frolov. [ZX]
No, you’re wrong about this. If I'm not mistaken, the flash drive has a strobe
signal... Then, it's enough to install one switch (either a hardware -
toggle switch), or a software one (trigger, etc.), and that's all telemarket...
OG> 6. In general, the principle of programming?
2KF: By the way, the same interesting...
Good luck! Evgeny. (Aka 2:5057/18.73) ■ The night is shorter than the day... The day will kill me... The world of illusions burns down in it. (C) Aria.
I’m sitting here listening to music and seeing that Oleg Golenkoff wrote Kirill Frolov:
OG> 1. How much does a flash drive cost?
150 rubles.
OG> 6. In general, the principle of programming?
kick and y are not flash drives