colecovision 24k mod need detect ay-3-8910

[chart45]

my coleco now have 24k ram thank to you guys now i will receive my thexder cart soon and i want to play

 

do i really need to hook the ay-3-8910 sound chip

 

what the cart look to start

 

i look the technical spec of the sgm i dont understand everything since im not familliar whit ic and programation

 

 

but if im right it look to port 50h 51h 52 and 53h

 

it's a0 and a1

 

can i use a sn74ls138 and use the a0 and a1 to output a cs to a8 and a9 of the ay chip????

 

im probably wrong that's why i.m here to learn and i dont mind if i have to order ic and programer and if the sound its not 100% i dont care my goal is to be able to play .. i dont want to creat another sgm since that thing is perfect but i want to play until eduardo get back on track. im sure im not the only one so other people will probably do the same if it's working

 

goal be able to play

 

 

[ColecoDan]

I thought everything Eduardo coded needed both the memory and the sound chip so unfortunately you are probably going to have to get the sound chip otherwise the code that checks for it will see it is not there and I think won't play the game. Some games are getting created that don't need the sound chip but I think this is not one of them.

[chart45]

i already ordered the ay-3-8910 and i try to understand how to hook it up to the coleco

[chart45]

found that maybe it's close

 

[chart45]

5-11, nanochess could you look a this to see if im going some where or im not on track at all

 

thanks guys

[+5-11under]

Looks like a good start. I've got a couple of those chips already, too.

You just have to figure out the decoding... not sure if the addresses match the SGM yet or not... and figure out the clock. I think it's normally 1/2 the Z80 clock frequency, so use a flip-flop to divide it... that's just a guess.

[chart45]

Looks like a good start. I've got a couple of those chips already, too.

You just have to figure out the decoding... not sure if the addresses match the SGM yet or not... and figure out the clock. I think it's normally 1/2 the Z80 clock frequency, so use a flip-flop to divide it... that's just a guess.

i found this circuit on google its just a starting point.... i read that the sgm look for 50h to 53h for me that mean nothing but for you probably

 

ill try to find info in the z80 programation

 

nano did the software to detect the sgm

so i think he could help us with that part.

[+5-11under]

I've been trying to wrap my head around easily accessing all the SGM I/O ports, but I think it's getting too late in the night for this. I'm getting closer, and maybe another day I'll be able to figure it out completely.

 

You'll probably also need the bottom 8K to be able to be switched between BIOS and RAM, otherwise the initial test will fail and you probably won't be able to play the SGM games (besides the ADAM conversions).

[+nanochess]

Your connections for 74LS138 look so overly complicated, you should decode port $50 from A4-A7 / IORQ in 74LS138 inputs.

 

The clock input of AY-3-8910 should go to expansion port clock that outputs 3.579545 mhz.

 

I don't want to mess with the sound chip datasheet for A0/A1/RD/WR but you should be able to solve it, otherwise you wouldn't get any fun

 

If you get the sound connected right, my software will detect it without problems

[chart45]

ok i foud this circuit to show the clock with a 74ls74

 

 

but if i dont have to use this only to plug on the expension port that will be easier but i was thiking that the clock was to high for the ay chip

[chart45]

ok now I try to understand address decoding so don't laugh at me "si chu dans le champs"

 

ok so port 50h a0=0 and a1=0

51h a0=0 and a1=1

52h a0=1 and a1=0

53h a0=1 and a1=1

 

the ay-3-8910 to be read need bdir=0 bc2=1 bc1=1

write bdir=1 bc2=1 bc1=0

 

the decoding is made by the 74ls138 chip

 

 

ok on the z80 when its time to read iorq=1 and rd=1 than iorq=0 rd=0

write iorq=1 and wr=1 than iorq=0 wr=0

 

but I don't understand how to decode a0 and a1 or why a4 - a7 /iorq since iorq is always 0 if rd or wr is not selected

 

is that a4 a7 are duplicate ???

 

the way to hook the chip will be very appreciate but i'm here to learn and understand so please give me the explanation

 

is where im at

 

[+5-11under]

I/O ports 80 to FF are used by existing items, so if you make sure A7 is set to zero (connect to G2Bbar), then you'll make sure you don't get any contention between the new I/Os and the original I/Os.

 

For the A, B, and C inputs, you then need to differentiate between ports 50/51/52, 53, and 7F, so that if one is being accessed, it won't be mistaken for one of the others. This is a bit trickier, because 53 is very similar to 50/51/52. A2 can be used to differentiate between 7F and the others. A1<AND>A0 can be used to differentiate between 53 and 50/51/52.

[chart45]

a0<and>a1 mean with resitor and diodes to c

Edited October 15, 2013 by chart45

[+5-11under]

a0<and>a1 mean with resitor and diodes to c

Yes, an AND gate with A1 and A0 as inputs. Either resistor/diode logic or otherwise.

[chart45]

ok now im at that point i put bc2 to 5v since is always high to read or write. i draw the address decoder like you said 5-11 but i cant figure it out. i think i have to use the y0 y4 and y7 with a 74ls00 to output the bdir and bc1 but since i cant understand the decoding i cant draw the bc1 and bdir. do you know a site or a pdf that could help me to understand the decoding part...

 

[chart45]

Your connections for 74LS138 look so overly complicated, you should decode port $50 from A4-A7 / IORQ in 74LS138 inputs.

 

The clock input of AY-3-8910 should go to expansion port clock that outputs 3.579545 mhz.

 

I don't want to mess with the sound chip datasheet for A0/A1/RD/WR but you should be able to solve it, otherwise you wouldn't get any fun

 

If you get the sound connected right, my software will detect it without problems

 

clk of the ay chip direct to the clk of the expension port nothing in between resistor ????

 

have you seen a good copy of that circuit from opcode for the audio out it look like the 3 chanel goes to audio out(pin 56) of the expension port with resistor and I think a capacitor

 

[chart45]

now i output audio and clk if someone could comfirm im still on track please

 

 

still trying to figure the decoding part but i dont understand im missing to much of theory

[chart45]

5-11 ,nanochess help

[+5-11under]

The PM I sent you has pretty much everything I know about decoding the required port addresses.

For the AY chip, it looks like you'll need to look at the datasheet for the BC1, BC2 and BDIR specifications. Page 2. Sorry, I haven't looked more than 2 minutes at this data sheet, but it looks "relatively" simple. Figure out what status (0 or 1) you need for each pin for each case. Write it down and see if it makes some sense, then try to figure out the logic to get there.

[+nanochess]

Check the datasheet at http://map.grauw.nl/resources/sound/generalinstrument_ay-3-8910.pdf

 

BDIR=0 BC2=1 BC1=0 must be generated by default (inactive chip, that is not accessed)

BDIR=0 BC2=1 BC1=1 must be generated by port 52H

BDIR=1 BC2=1 BC1=0 must be generated by port 51H

BDIR=1 BC2=1 BC1=1 must be generated by port 50H

 

So go ahead and make decoding logic that generates these signals

 

Note that in datasheet you can see there are three possible BDIR/BC2/BC1 combinations for inactive chip, choose the best one to reduce logic use.

 

For decoding you'll need only IORQ, A7-A4 and A1-A0.

Edited October 19, 2013 by nanochess

[chart45]

that's my problem i cant figure the output since i dont understand what go in i know when z80 output rd or wr iorq go low . i read a lot of stuff on the z80 and 74ls138 but nowhere i found info on what the address output i know i have a big lack of knowledge about that level of electronic but i try very hard cause i really want to play those sgm game ... could you tell me if i have to use the 74ls00 with the output of the 74 ls138 like the circuit i found on google and i will try every possibility thanks for your time 5-11

[chart45]

nanochess i was writing the msg when you post ill try thanks

[chart45]

ok now i receive everything i need i think

 

74ls74 to divide clock

74ls 138 to decode address for sound,24k and lower 8 k

 

64k chip

32k chip

ay-3-8910

 

now with my new baby girl i dont have a lot of time to learn all this decodind technic but i will try my best to be able to play all those sgm game

 

Edited November 8, 2013 by chart45

[+Yurkie]

ok now i receive everything i need i think

74ls74 to divide clock

74ls 138 to decode address for sound,24k and lower 8 k

64k chip

32k chip

ay-3-8910

now with my new baby girl i dont have a lot of time to learn all this decodind technic but i will try my best to be able to play all those sgm game

Wow that's a lot of chips...gonna be tough to put that together on a DIY PCB

[chart45]

if i understand what 5-11 pm me ill need only one 74ls138 but im reading the z80 manual to understand how everything works