namco 163 general question and info thread

A place that you can discuss reproduction of classic titles or "licensed-for-reproduction" homebrew for personal use.

Moderators: B00daW, Moderators

Forum rules
1. NO BLATANT PIRACY. This includes reproducing homebrew less than 10 years old, with the exception of free software.
2. No advertising your reproductions, with the exception of free software.
3. Be nice. See RFC 1855 if you aren't sure what this means.
Post Reply
FrankWDoom
Posts: 243
Joined: Mon Jan 23, 2012 11:27 pm

namco 163 general question and info thread

Post by FrankWDoom » Sat Jul 04, 2020 10:44 am

edit: expanding the scope of this thread since I have more questions than just sram

I want to add sram to this namco 163 board. I have several questions.

first, reference pics (kaiju monogatari).

board:
namco 163 111F0
namco 163 111F0
existing battery circuit to 163:
namco 163 111F0 battery circuit
namco 163 111F0 battery circuit
the the mapper pins in the pic are 13-24. the pins connected to the circuit are

19 +5Vcc (left)
22 /$E000.7 (right)

for pin 22, the rom i'm looking at is writing 0 to the corresponding register bit, so pin 22 should be high?


component questions:

what are:

1A and 2B (2B is connected to 5V on the cart edge)
the brown band smd component
the IBT chip


ram questions:

the address and data pins are self explanatory. for the remaining pins does this look right?

20 /CE1 - mapper pin 40 WRAM /CE
22 /OE - GND
26 CE2 - VCC
27 R/W - mapper pin 29 R/W (currently only connected to cart edge 14)
28 VCC - ?

for VCC, where do i tap 5V for that and what components do I need to add? (see next post for related material)

I looked at a TKROM board for some reference, and it had /CE1 permanently grounded and /OE going to the /CE pin on the mapper. Does it matter which way it goes? I'll need to have a pull up resistor on the grounded pin right? Does that dictate which pin it should be?
Last edited by FrankWDoom on Wed Jul 15, 2020 10:24 am, edited 3 times in total.

FrankWDoom
Posts: 243
Joined: Mon Jan 23, 2012 11:27 pm

Re: adding sram to a battery backed namco 163 board

Post by FrankWDoom » Sat Jul 04, 2020 10:44 am

here are two more namco 163 games, using the same board (60-16), one with sram and one without.

king of kings, with sram
namco 163 60-16 sram
namco 163 60-16 sram
namco 163 60-16 sram battery circuit
namco 163 60-16 sram battery circuit
kaiju monogatari, without sram
namco 163 60-16 no ram
namco 163 60-16 no ram
namco 163 60-16 no ram battery circuit
namco 163 60-16 no ram battery circuit
there are 3 components unpopulated on the kaiju board that i'm assuming are sram related.

from what I see the path from BAT+ is the same at least to where 1A and 2B are connected (2B is 5V again).

the left end of the white band component (?) is connected to the 103 resistor next to it on the lower leg. I'm not sure about any other connections. I can't find any connections to the battery. on those components but it's mostly trial and error searching. unfortunately most of the vias are under one of the globs (mapper I think)

lidnariq
Posts: 9765
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: adding sram to a battery backed namco 163 board

Post by lidnariq » Sat Jul 04, 2020 12:34 pm

FrankWDoom wrote:
Sat Jul 04, 2020 10:44 am
what are:

1A and 2B (2B is connected to 5V on the cart edge)
Diodes
the brown band smd component
Capacitor
the IBT chip
NPN transistor.


Some games back up the 128 bytes of RAM inside the 163 instead.

FrankWDoom
Posts: 243
Joined: Mon Jan 23, 2012 11:27 pm

Re: adding sram to a battery backed namco 163 board

Post by FrankWDoom » Sat Jul 04, 2020 4:33 pm

lidnariq wrote:
Sat Jul 04, 2020 12:34 pm
FrankWDoom wrote:
Sat Jul 04, 2020 10:44 am
what are:

1A and 2B (2B is connected to 5V on the cart edge)
Diodes
the brown band smd component
Capacitor
the IBT chip
NPN transistor.


Some games back up the 128 bytes of RAM inside the 163 instead.
thanks for that. do you have any thoughts on the pin connections?

i'm pretty confident this rom is not expecting anything in audio ram to be saved. I think i could get away with cutting the battery circuit to the mapper and running that to ram. for the mapper i could tie the pin to 5v from the other side of the chip. does that sound reasonable?

lidnariq
Posts: 9765
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: adding sram to a battery backed namco 163 board

Post by lidnariq » Sat Jul 04, 2020 5:22 pm

Yes, you could just remove all the battery-backup stuff and tie all three power pins to +5V.

Pin 22 in OEM PCBs seems to be externally tied to ground for unknown reasons.

FrankWDoom
Posts: 243
Joined: Mon Jan 23, 2012 11:27 pm

Re: namco 163 general question and info thread

Post by FrankWDoom » Wed Jul 15, 2020 10:47 am

I've managed to get sram installed and play a game that makes use of it from eproms.

both prg and chr use the nintendo-prg pinout. however, my AVS was not happy when the prg eprom /OE was connected to GND. I changed it so both /OE and /CE are on the /CE line, and it's working.

for reference, wiring is

eprom pin 3 in hole 1
pin 1 up
pin 2 -> hole 22
pin 24 -> hole 20/pin 22
pin 30 up (nc for now, for 256K roms would need to connect to the 163 directly for A17)
pin 32 -> hole 30

pin 31 also needs to be bent up to physically clear the board

the sram chip is attached to the back of the board, face down, to line up pins as best as possible. for now, the sram, is only connected to the console's 5V line. i need sram to be battery backed, where only the 163 is right now. i don't need the 163 on battery, so my plan is to cut the battery circuit to the 163 and send it to the ram chip, and connect the 163 to the console 5v only.

sram wiring:
pin 20 -> 163 pin 40
pin 22 -> pin 20
pin 26 -> prg 5V
pin 27 -> 163 pin 29
pin 28 -> prg 5V (for now)

pin 1 is nc so I left it up
when i get the ram chip on battery power, i need to add a resistor to put the ram in standby when powered down. I'm guessing I'll want to separate /OE and /CE so they're not both drawing on the battery. maybe add a diode to bridge them so only is drawing?
IMG_20200714_190743.jpg
IMG_20200714_190736.jpg
please excuse the sloppy wiring, took some trial and error to get it together. note the eproms/sockets interfere with mounting posts in the original shell. i'm not planning on putting this board back in that shell so i made use of the mounting holes to thread wires through.
Last edited by FrankWDoom on Wed Jul 15, 2020 11:11 am, edited 1 time in total.

FrankWDoom
Posts: 243
Joined: Mon Jan 23, 2012 11:27 pm

Re: namco 163 general question and info thread

Post by FrankWDoom » Wed Jul 15, 2020 11:09 am

expansion audio question:

the rom i put on the board uses both nes and exp audio. the exp audio is very quiet- barely audible when tv volume is adjusted for normal nes audio volume.

the donor board (kaiju monogatari, 111F0) appears to route exp audio from 163 to the cart edge directly, no components on the path. nes audio is bridge to the output right above the cart edge pins.

what can i do to boost exp audio output to match nes audio levels? some kind of amp maybe? or will it take a rom hack to adjust volume settings?

how do other games using this mapper deal with this? according to the wiki there are various submappers to identify discrepancies in audio volume. is that all down to programming?

I'm only able to test on an AVS console at the moment, if that makes a difference.

lidnariq
Posts: 9765
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: namco 163 general question and info thread

Post by lidnariq » Wed Jul 15, 2020 11:44 am

FrankWDoom wrote:
Wed Jul 15, 2020 11:09 am
the donor board (kaiju monogatari, 111F0) appears to route exp audio from 163 to the cart edge directly, no components on the path.
That's normal
nes audio is bridge to the output right above the cart edge pins.
That's a cart that assumed no expansion audio.

The N163 boards with sound have a resistor between the pins "AUDIO FROM 2A03" and "AUDIO TO RF", and the size of that resistor – plus some unknown variability inside the N163 IC itself – is what sets the relative volume. We've found boards with 4.7k, 10k, 15k, or 22k resistors, and sometimes the same game with different sizes but the same mix balance.

You'll either need to use a potentiometer to adjust the balance after you've assembled it, or else take a chance of needing to change it after the fact.

lidnariq
Posts: 9765
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: namco 163 general question and info thread

Post by lidnariq » Wed Jul 15, 2020 12:19 pm

FrankWDoom wrote:
Wed Jul 15, 2020 10:47 am
when i get the ram chip on battery power, i need to add a resistor to put the ram in standby when powered down. I'm guessing I'll want to separate /OE and /CE so they're not both drawing on the battery. maybe add a diode to bridge them so only is drawing?
I'd strongly recommend reusing the hybrid-powered power supply already on the board and let it power the 163 anyway. Otherwise you're basically going to be rebuilding an exact copy...

FrankWDoom
Posts: 243
Joined: Mon Jan 23, 2012 11:27 pm

Re: namco 163 general question and info thread

Post by FrankWDoom » Wed Jul 15, 2020 1:06 pm

lidnariq wrote:
Wed Jul 15, 2020 12:19 pm
FrankWDoom wrote:
Wed Jul 15, 2020 10:47 am
when i get the ram chip on battery power, i need to add a resistor to put the ram in standby when powered down. I'm guessing I'll want to separate /OE and /CE so they're not both drawing on the battery. maybe add a diode to bridge them so only is drawing?
I'd strongly recommend reusing the hybrid-powered power supply already on the board and let it power the 163 anyway. Otherwise you're basically going to be rebuilding an exact copy...
I was intending to steal the hybrid output from the 163 for the sram, i didn't want to try to recreate it separately. Do you think it would be ok if the 163 and sram shared that one output? i don't need the 163 to be battery backed so i could find another 5v for it.
lidnariq wrote:
Wed Jul 15, 2020 11:44 am
That's a cart that assumed no expansion audio.

The N163 boards with sound have a resistor between the pins "AUDIO FROM 2A03" and "AUDIO TO RF", and the size of that resistor – plus some unknown variability inside the N163 IC itself – is what sets the relative volume. We've found boards with 4.7k, 10k, 15k, or 22k resistors, and sometimes the same game with different sizes but the same mix balance.

You'll either need to use a potentiometer to adjust the balance after you've assembled it, or else take a chance of needing to change it after the fact.
so cutting that trace and bridging and connecting with a resistor (of some value tbd) should bring exp audio levels up? could you explain how that works? sorry i just don't know enough about circuit design.

reviewing the globtop boards from post #2, one of the king of kings 10k resistors unpopulated on the kaiju board appears to bridge the audio lines. i don't have the kaiju glob board in front of me so I don't know how it's getting nes audio back out of the cart atm. I will look into that.

lidnariq
Posts: 9765
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: namco 163 general question and info thread

Post by lidnariq » Wed Jul 15, 2020 2:11 pm

FrankWDoom wrote:
Wed Jul 15, 2020 1:06 pm
I was intending to steal the hybrid output from the 163 for the sram, i didn't want to try to recreate it separately. Do you think it would be ok if the 163 and sram shared that one output? i don't need the 163 to be battery backed so i could find another 5v for it.
On the one hand, I don't see why not.

On the other hand, every 163-using game with external RAM battery-backs both the 163 and the RAM, so it may well be easier or simpler to just do that instead.
so cutting that trace and bridging and connecting with a resistor (of some value tbd) should bring exp audio levels up? could you explain how that works? sorry i just don't know enough about circuit design.
It's just a resistor divider serving as a mixer. One of the resistors is invisible, inside the 163.

Post Reply