Some questions about hardware

By MSXGuy

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MSXGuy's picture

12-01-2022, 04:17

Hi. New to the forum, but have been using MSX for some time now.

I have a few questions, maybe some expert here could help me?

First one is, does it exist any RAM IC with the same pin out as the Mitsubishi M5K4164ANP. Datasheet in the link below:
https://datasheetspdf.com/datasheet/M5K4164ANP-15.html

Also, I am not interested in using memory mappers or similars.

The second question: what is the highest cassette baud rate an MSX2 could be able to load (from PC to MSX). I have been doing some experiments with mixed results, but I don't know if that is because I did something wrong. I am using either CAS files or WAV files directly.

Third: what is the most recommended .CAS converter and/or player for Windows? I read somewhere that it is possible to use BlueMSX to convert from CAS to WAV, but I couldn't find a way to do it.

Another question is: about cartridge slots: it seems there is a RESET pin in the cartridge slots. I could be wrong, but I assume it is used to hardreset the computer. If my assumption is correct, to reset it through the cartridge slot, should it be shorted to ground or to 5v? Also, removing a game cartridge from the slot while the computer is on, it could damage the PC. What would happen if somehow we disconnect the 5v and 12v lines from the cartridge slot and then we remove the cartridge, but the computer is still on? Besides the obvious software glitches etc, could that avoid damaging the computer?
Lets say I modify my MSX and I add a push switch at the bottom of the slot. As soon as the user pulls the cartridge one millimiter, the switch is un-pressed and breaks the 5v and 12v connections to the cartridge slot.

Last question: excuse my poor knowledge about this, but in what slot and memory addresses is located the expansion bus of the Mitsubishi ML-G10 (I am refering to the next page: https://www.msx.org/wiki/CON-SUP_Connector ). It seems this information is missing in the wikia.

Thank you.

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By Jipe

Paragon (1528)

Jipe's picture

12-01-2022, 09:45

for the RAM exist many chips search 64kx1 DRAM on google Wink
for the slot mapping see on : https://www.msx.org/wiki/Mitsubishi_ML-G10

By gdx

Enlighted (5011)

gdx's picture

12-01-2022, 10:18

The /Reset pin is not to make a initialization but this is a reset signal from the MSX.

There is no point in removing MSX cartridges that are on.

By Grauw

Ascended (10306)

Grauw's picture

12-01-2022, 11:13

The reset signal is an output signal, not an input. It’s there so that cartridges can revert to their initial state when the computer boots and resets. Tying it to 5v or ground will cause a short.

About the ML-G10 expansion bus, I don’t see any slot select signal (/SLTSL) on the pinout you linked to, so I don’t think the expansion bus is mapped to a slot.

By MSXGuy

Supporter (4)

MSXGuy's picture

14-01-2022, 03:11

Jipe wrote:

for the RAM exist many chips search 64kx1 DRAM on google Wink
for the slot mapping see on : https://www.msx.org/wiki/Mitsubishi_ML-G10

Thank you. Related to the memory ICs I already found what I was looking for.

gdx wrote:

The /Reset pin is not to make a initialization but this is a reset signal from the MSX.
There is no point in removing MSX cartridges that are on.

I am not asking if there is a point in removing cartridges, but about how the MSX works.

Grauw wrote:

The reset signal is an output signal, not an input. It’s there so that cartridges can revert to their initial state when the computer boots and resets. Tying it to 5v or ground will cause a short.

About the ML-G10 expansion bus, I don’t see any slot select signal (/SLTSL) on the pinout you linked to, so I don’t think the expansion bus is mapped to a slot.

Thank you for your reply, very useful. As for the RESET, totally understood. For the Commodore 64, the expansion port/cartridge slot has a RESET signal that resets the computer it is made low. Is there any way to achieve something similar in an MSX?

As for the ML-G10, are you aware of some extra documentation about that expansion bus, other than the one in this MSX wikia?

Also, my last question was if we break the 5 and 12volt connection to the cartridge slot and then we pull the cartridge, can the MSX and/or cartridge be still damaged?

By gdx

Enlighted (5011)

gdx's picture

14-01-2022, 09:22

MSXGuy wrote:

I am not asking if there is a point in removing cartridges, but about how the MSX works.

I know. My first sentence explained how the /Reset pin works because you don't seem to understand it. Grauw made the same explanation but from a technical point of view.
The second sentence was to tell you that I think it's not a good idea to add a switch in the cartridge slot like you explained. It's not for nothing that it was removed from the MSX standard. It's better to put a switch with a pull-up resistor on slot selection signal if you want ignore a cartridge ROM or put a system that prevents removing the cartridge when the MSX is on.

MSXGuy wrote:

For the Commodore 64, the expansion port/cartridge slot has a RESET signal that resets the computer it is made low. Is there any way to achieve something similar in an MSX?

No. This can be done by software.

MSXGuy wrote:

Also, my last question was if we break the 5 and 12volt connection to the cartridge slot and then we pull the cartridge, can the MSX and/or cartridge be still damaged?

I think yes, it's possible especialy with some expansions or interfaces. That's why I said that there is no point in removing cartridges. It was just advice.

By Parn

Paladin (672)

Parn's picture

14-01-2022, 19:17

The ML-G10 bus expansion connector seems to be good only for port-based devices and some kind of video stuff.