Author |
Topic: Flash cart
question (neviksti) (Read 1547
times) | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
 
|
 |
Flash cart question
(neviksti)
«
on: Feb 23rd a 09:49:18pm » |
   |
Have you manage to build your new flash cart
design, or are you still working on designing
the PCB?
mainly, the thing I am looking
to build at the moment, is the cart
reader/writer, to start with. |
|
Logged | | | |
neviksti
Newbie
Karma:
42
[applaud]
[smite]
Gender:
Posts: 45
|
 |
Re:Flash cart question
(neviksti)
« Reply
#1 on: Feb 24th a 04:24:26pm » |
|
The design is done ... I just need to lay out
the PCB, make some boards, populate one, and see
if it works. Which takes longer than it
may sound.
If all you want is the cart
reader/writer so you can dump SRAM and ROM from
a cart ... and change the SRAM on the cart as
well... then I can just tell you how to hook it
up. It's a pretty simple circuit so you
could just use a protoboard for this one.
Its just that soldering the cartridge connector
would be annoying with a protoboard. I
guess you could use ribbon cable and solder a
little wire to each pin of the connector ... and
then solder the wires into the protoboard as
necessary.
Anyway, since I would like a
flash cart, I'm going to layout and order a PCB
for the programmer and the cart (hopefully
sometime this century  ). It'll be
much easier to put together with a PCB (and
it'll be more 'solid'). So I don't feel
like making a protoboard of something like that
(I trust the programmer to work).
Here's
the deal ... there is very little hardware in
the programmer because the burden is put on the
software. So I need to make a program for
you if you want to use the design.
(actually it's a pair of programs ... one for
the PC, probably written in C... and one for the
AVR microcontroller, written in ASM ) It
wouldn't be that hard to write the programs, its
just that, well ... I'm not known for having my
programs work the first try. It usually
doesn't take me long to fix up the 'first run'
bugs, but the problem here is that you will have
the hardware ... I will have the software ...
and we'll have to work together to figure out
who made what errors, and debug
everything.
You seem like a smart
guy. So if you're willing to go through
the debugging process with me ... I'm willing to
tell you what to do to make the programmer, and
I'll write the software while you make the
hardware.
Let me know if this sounds like
a good deal to you. |
|
Logged | | | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
|
|
Re:Flash cart question
(neviksti)
« Reply
#2 on: Feb 24th a 06:50:47pm » |
|
That would be a good deal.
how would the
microcontroller used in the flashcart
reader/writer be programmed?
Im currently
working on readying a cart connector (from a
broken snes) to attach onto a proto pcb.
|
|
Logged | | | |
neviksti
Newbie
Karma:
42
[applaud]
[smite]
Gender:
Posts: 45
|
|
Re:Flash cart question
(neviksti)
« Reply
#3 on: Feb 24th a 09:06:05pm » |
|
part list:
Atmel AVR
microcontroller: AT90s8535 - 32 I/O
pins
Parallel Port connector
octal latch:
74HCT573
SNES cartridge connector
+5V
regulator (500mA, TO-220 package):
LM78M05CT
47 uF electrolytic cap
47 pF
tantalum cap
9V AC/DC adapter 500 mA
power
adapter receptacle
8 Mhz crystal (parallel
resonance)
18pF caps (two) or whatever value
the crystals
require
=======================================
a
few notes:
Yeah, the power supply is beefer
than is necessary. You can tone it done if
you want.
I'd suggest soldering a DIP socket
in for the atmel and plugging the chip in
instead of soldering the atmel directly to the
board. Why? Because the atmel chip is
really neat and handy to use in projects ...
you're basically building a programmer for the
atmel as well. So later you can program an
atmel and stick a 'brain' in some of your other
projects
OK, here's
the wiring:
power
supply:
connect +9V from AC/DC adapter to Vin
of regulator
ground of adapter to ground of
board
Vout of regulator is the +5V for
everything
put the two caps (47pF, 47uF) in
parallel across the +5V and
GND
Cartridge Connector
every
pin is fairly obvious
connect to atmel,
power, or octal latch as defined
below
connection for pins not described
below:
pins 1-4,28-31,32-35, 59-62 = "extra
tabs"
just leave these
unconnected for now
pin 18 =
/IRQ
leave this unconnected
as well
pin 26 =
/RESET
connect to
+5V
pin 24,55 = Security chip
out
just leave these
unconnected for now
pin 25,56 = Security chip
in
you can ground
these
or you could just
leave these unconnected for now
pin 57 = no
connect
AT90s8535 - 32 I/O
pins
http://www.atmel.com/atmel/acrobat/1041s.pdf
for summary datasheet
AREF = AVCC = VCC =
+5V
AGND = GND
crystal connects to
XTAL1, XTAL2
the two crystal caps ( ~ 18pF),
from XTAL1 to GND, and XTAL2 to
GND
PORTB
B0 - ready
to receive (to PC)
B1 -
latch (/LE of octal
latch)
B2 - /RD (cart
connector pad 23)
B3 - /WR
(cart connector pad
54)
B4-B7 - communication
to PC
B4
- /SS -
grounded
B5
- MOSI
B6
- MISO
B7
- SCK
PORT
C:D
address
lines
C0-C7 - address lines
A0-A7
D0-C7 - address lines
A8-A15
PORT A
data
lines - (data to cartridge) and (upper 8 address
lines - to octal
latch)
octal
latch
A0-A7
connect to D0-D7 of octal
latch
Q0-Q7
of octal latch connect to BA0-BA7 of cartridge
connector
/OE
of octal latch connect to
GND
cart
connector
A0-A7
connect to D0-D7 of cartridge
connector
Parallel port - 8 data, 4
control, 5
status
data
D0 - pin2 -
MOSI
D1 - pin3 -
SCK
D6 - pin8 - /CART (cart
connector pad 49)
D7 - pin9
- /RESET (of
Atmel)
status
S4 -
pin13 - MISO
S5 - pin12 -
ready to receive (from
atmel)
gnd
pins
18-25
connect to ground of
board
====================================
Ok,
that should be all.
Oh, if you just need an
easy place to get everything, Digikey has all
the parts available you should need.
Let
me know if I left anything out.
BTW, the
program I'm going to write is just a simple
command line prog. Once it works, I'll
release the code and someone can make a nice
little VisualBasic or MFC interface or
something, for it if they want. I don't
usually find the need to do that stuff.
|
|
Logged | | | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
|
|
Re:Flash cart question
(neviksti)
« Reply
#4 on: Feb 24th a 11:16:51pm » |
|
A question, relating to digikey.
I did a
bit of searching around, and came to these part
numbers.
Atmel: AT90S8535-8PC-ND
Octal
Latch: 296-2128-5-ND
47 uf electrolyte
cap: P5870-ND
5V power regulator:
LM78M05CT-ND
8Mhz crystal: 300-5010-ND
18pf caps for crystal: P4003A-ND
are
these okay, or are there other digikey part #'s
that would be better?
I had difficulty
finding the 47pf tantalum cap.
|
| « Last Edit: Feb
24th a 11:40:57pm by CaitSith2 » |
Logged | | | |
neviksti
Newbie
Karma:
42
[applaud]
[smite]
Gender:
Posts: 45
|
|
Re:Flash cart question
(neviksti)
« Reply
#5 on: Feb 24th a 11:50:30pm » |
|
>what does 47 pf convert to in uf?
uF
= micro-Farad = 10^-6 F
pF = pico-Farad =
10^-12 F
These are the standard units
you'll see capacitors sold in. Although
they do sell these freaky 1 F capacitors now ...
about the size of a quarter! Amazing, I
don't know how they do it. So I guess you
can add just plain Farad to that list now. Also
people use nF - nano-Farad when talking about
values sometimes, although they usually aren't
listed in such quantities.
So I guess
someone could call it:
0.000047
uF
That exact value doesn't really matter
anyway. It's just that's a common value
that's easy to obtain.
Hmmm... I just
checked digikey. I see why you ask
now.
The bigger the better I guess ...
just keep the impedance down. That's the
whole point of a tantalum cap (you actually
don't even need a tantalum cap ... any low
impedance one will do).
You see, for a
power supply, the voltage regulator tries to
keep a constant voltage but it helps to add in
capacitors to maintain this voltage during quick
changes in current (very common with digital
circuits). The electrolytic cap holds a
lot of charge and can supply large current when
needed, however it has a high "impedance" and
takes awhile to respond. The tantalum caps
don't really hold as much (for same amount of
$), but have a lower ESR (Equivalent
Series Resistance) and therefore can respond
quicker to changes in current.
Make
sense?
Again, I'm not an engineer or
electrician, so that's just my take on non-ideal
capacitors. Also, I usually don't take
much time thinking about capacitor values.
I probably should have said 47nF, go for 0.047uF
or higher then.
In reality, the circuit
will probably work without either of those caps,
but I've seen really weird errors that can't be
traced back to anything except something strange
going on with the power supply. It's
easier to shell out the 50 cents or whatever and
not worry about it. |
|
Logged | | | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
|
|
Re:Flash cart question
(neviksti)
« Reply
#6 on: Feb 25th a 12:22:52pm » |
|
I think I know what else I could use the atmel
chip for.
once I know the APU pinout, I
can use the atmel chip to interface the APU to
the PC.
besides that, the atmel seems to
be very versatile and usefull for a lot of
things. |
|
Logged | | | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
|
|
Re:Flash cart question
(neviksti)
« Reply
#7 on: Feb 25th a 10:08:01pm » |
|
Based on my continuity testing, both on an
actual working snes, and on the cart connector
that I got from a busted snes, cart pins 5 is
connected to 36, and pin 27 is connected to
58
nothing else, as far as I know is
connected together.
oh yeah, I now
have a ribbon cable connected to the cart
connector, making it ready for use in
contruction.
I just have to order the
parts. |
|
Logged | | | |
neviksti
Newbie
Karma:
42
[applaud]
[smite]
Gender:
Posts: 45
|
|
Re:Flash cart question
(neviksti)
« Reply
#8 on: Feb 26th a 10:21:51am » |
|
>Based on my continuity testing, both on an
actual
>working snes, and on the cart
connector that I got
>from a busted snes,
cart pins 5 is connected to 36,
>and pin
27 is connected to 58
Yes.
pin 5 = pin
36 = GND
pin 27 = pin 58 = VCC
I
thought you already had a document showing what
each pin of the cartridge connector (that we're
using) is for. If not I can give you some
of my documentation.
>oh yeah, I now
have a ribbon cable connected to the
>cart connector, making it ready for use
in contruction.
>
>I just have to
order the parts.
Sounds good! |
|
Logged | | | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
|
|
Re:Flash cart question
(neviksti)
« Reply
#9 on: Feb 26th a 10:58:31am » |
|
I need the documentation on the cart connector.
|
|
Logged | | | |
neviksti
Newbie
Karma:
42
[applaud]
[smite]
Gender:
Posts: 45
|
|
Re:Flash cart question
(neviksti)
« Reply
#10 on: Feb 26th a 06:15:47pm » |
|
>I need the documentation on the cart
connector.
OK, I uploaded one of my docs
here:
cart-chip-pinouts.html
Sorry
about the pop-ups and such ... but that's the
only web-space I have to trade files
on.
|
|
Logged | | | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
|
|
Re:Flash cart question
(neviksti)
« Reply
#11 on: Feb 26th a 06:40:53pm » |
|
No problem with the popups (popup
killer)
I outlined a set of
schematics on paper, to help me with assembly of
the 'cart/atmel reader/writer'
I like
your idea of directly implementing the atmel
chip programmer into the cart reader/writer
hardware.
Would this thing also be
capable of accessing the DSP chips, (for getting
output data from a set input) |
| « Last Edit: Feb
26th a 08:12:57pm by CaitSith2 » |
Logged | | | |
neviksti
Newbie
Karma:
42
[applaud]
[smite]
Gender:
Posts: 45
|
|
Re:Flash cart question
(neviksti)
« Reply
#12 on: Feb 26th a 10:02:42pm » |
|
>Would this thing also be capable of
accessing the DSP
>chips, (for getting
output data from a set input)
Why
not? On a DSP cart the DSP chip is
completely separate from the ROM and SRAM.
So we can directly access all of it (unlike the
SFX and S-DD1). Since our programmer can
read/write to any location on the cart there is
no problem.
Remember the hardware
is simple ... the brunt of the work is put on
the software. Which means it takes a bit
more to setup, but also means it is much more
versatile. So something like that would
just require more programming work. |
|
Logged | | | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
|
|
Re:Flash cart question
(neviksti)
« Reply
#13 on: Feb 26th a 10:57:44pm » |
|
Ok, so DSP is fully accessable, SDD1 and SFX
isn't. I wonder what other hardware is not
fully accessable. my current guess would
be SPC7110.
I do wonder though if I could
access the RTC on my FEOEZ cart directly (for
reading as well as writing).
This
hardware could potentially be integrated with an
emulator like zsnes, for playing certain
unemulated DSP chip games (some racing game that
doesn't have a gun on the hood and therefore
sucks, others), maybe use other chips that are
fully accessable. |
|
Logged | | | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
|
|
Re:Flash cart question
(neviksti)
« Reply
#14 on: Feb 27th a 12:52:56pm » |
|
I have managed to find the spare 5V power
regulator I had from a broken snes. now it
is just a matter to take a trip to the local
electronic stores and get a power adaptor
recepticle (to fit spare snes power adaptor),
some capacitors, and some kind of connection
system that only connects one way.
thats
the power supply taken care of. |
|
Logged | | | |
neviksti
Newbie
Karma:
42
[applaud]
[smite]
Gender:
Posts: 45
|
|
Re:Flash cart question
(neviksti)
« Reply
#15 on: Feb 27th a 01:41:00pm » |
|
>I do wonder though if I could access the RTC
on my
>FEOEZ cart directly (for reading
as well as writing).
I have no
documentation (or a cartridge) of this. So
I'm not really sure. Worth a
try.
>This hardware could potentially
be integrated with an
>emulator like
zsnes, for playing certain unemulated
>DSP chip games ...
Not
really. This system transfers data too
slow. It wasn't designed for that. Yeah,
maybe I should have mentioned that earlier ...
it will take awhile to read/write large chunks
to the cartridge. It's not like its an
overnight thing ... I just don't think its fast
enough to work with an emulator.
Besides,
if you had the cartridge with those chips, you
could just play them on the real SNES |
|
Logged | | | |
CaitSith2
Jr. Member
Karma:
7
[applaud]
[smite]
Gender:
Posts: 69
You don't need a reason to help
people
|
|
Re:Flash cart question
(neviksti)
« Reply
#16 on: Feb 27th a 05:55:31pm » |
|
Finished building the power supply.
Now I
know what parts I have to get
online.
AT90S8535 - Atmel AVR
74HCT573
- Octal Latch
8 Mhz crystal
2 caps of
value crystal requires
40 pin DIP
socket.
Parts I should be able to get
locally.
Project box for power
supply
Heat Sink for power regulator
chip
Prototyping PCB board. |
| « Last Edit: Feb
27th a 09:02:18pm by CaitSith2 » |
Logged | | | |
neviksti
Newbie
Karma:
42
[applaud]
[smite]
Gender:
Posts: 45
|
|
Re:Flash cart question
(neviksti)
« Reply
#17 on: Feb 28th a 09:42:29am » |
|
>Heat Sink for power regulator chip
I
don't know what chip you got since you said you
pulled it out of a old SNES ... but we aren't
going to be drawing that much current, and the
chip was designed to handle a lot, so a heat
sink probably isn't necessary. (at least it
wasn't with the regulator I suggested)
However, it sounds like you're going to be using
this power supply for other things ... so
beefing it up a bit could be helpful .
>Prototyping
PCB board.
You probably can get this
from digikey as well. If you don't mind
shelling out more money for convenience you can
always get it from the local
Radioshack.
----------< | | | | | |
