SD2IEC - modifying a board, questions about two SD cards. - MMC2IEC

PCXT

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Wednesday, March 24th 2010, 2:18pm

SD2IEC - modifying a board, questions about two SD cards.

First of all, sorry for my English. And unfortunately I don't speak German.
I'm planning to build a two-card SD2IEC, but I can't build devices using SMD parts - so I'm going to design another board for it, using, if possible, only one layer (I'll figure it out if I have a schematic). I have some questions about designing it:
1. As I look to a Shadowolf's schematic here: http://www.pitsch.de/stuff/mmc2iec/index.htm#A11 there's a resistor R13 between PB2 and PA0 (IEC_ATN). According to 1.9 firmware config file, PB2 is an interrupt pin used by SD2 presence detect. Should this resistor be removed?
2. There's a way to connect a PCF8563 RTC to I2C, as I think to mark file dates properly. Are there any schematics showing how to connect this?
When RTC is powered up from circuit's power supply, it's OK, but after the power is turned off, RTC will loose its data. Will it be enough to connect CR2032 battery to RTC's Vcc thru 2 diodes (to avoid Vcc "charging" not rechargeable battery)?
3. Are there any pins/pins+small logic on the SD card socket, which can blink LED when the card is in use?

4. I'm going to build it on small boards to fit it easily in some old modem case). How long uC-SD cable can be, to not worry about interferences?
5. Should the IEC leads for Shadowolf's board be connected to two IEC connectors (like inside 1541)?

Thanks in advance
MCbx

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Unseen

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2

Wednesday, March 24th 2010, 2:29pm

Quoted from "PCXT"

1. As I look to a Shadowolf's schematic here: http://www.pitsch.de/stuff/mmc2iec/index.htm#A11 there's a resistor R13 between PB2 and PA0 (IEC_ATN). According to 1.9 firmware config file, PB2 is an interrupt pin used by SD2 presence detect. Should this resistor be removed?

Yes - the pads for that resistor were added to the PCB, but the resistor was meant to be left out. It was designed in in case there were problems with interrupt-based ATN handling, but was found not to be required after all so the pin was repurposed for the dual-SD-card-hack (now deprecated).

Quoted

2. There's a way to connect a PCF8563 RTC to I2C, as I think to mark file dates properly. Are there any schematics showing how to connect this?

I don't think so and I can't draw one right now.

Quoted

When RTC is powered up from circuit's power supply, it's OK, but after the power is turned off, RTC will loose its data. Will it be enough to connect CR2032 battery to RTC's Vcc thru 2 diodes (to avoid Vcc "charging" not rechargeable battery)?

Yes, that's the usual way to supply power to this RTC. You may want to use Schottky-type diodes (e.g. BAT85 or similiar) because they have a smaller voltage drop.

Quoted

3. Are there any pins/pins+small logic on the SD card socket, which can blink LED when the card is in use?

You could build something based on the clock line of the card.

Quoted

4. I'm going to build it on small boards to fit it easily in some old modem case). How long uC-SD cable can be, to not worry about interferences?

That depends on the cabling - some people have reported success with 30cm, others had trouble with just 10cm. Use a flat ribbon cable, don't leave out "redundant" GND or VCC lines.

Quoted

5. Should the IEC leads for Shadowolf's board be connected to two IEC connectors (like inside 1541)?

That's up to personal preference, the connectors of a 1541 are just wired in parallel after all.

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1 2 3	10 x=rnd(-1963):fori=1to81:y=rnd(1):next 20 forj=1to5:printchr$(rnd(1)16+70);:next 30 printint(rnd(1)328)-217

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AntaBaka

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3

Wednesday, March 24th 2010, 2:33pm

Quoted from "PCXT"

First of all, sorry for my English. And unfortunately I don't speak German.
I'm planning to build a two-card SD2IEC, but I can't build devices using SMD parts - so I'm going to design another board for it, using, if possible, only one layer (I'll figure it out if I have a schematic). I have some questions about designing it:

First question: Why not take an already existing layout? It's one layer and no SMD.
The only real difference is that it's using the LarsP-Variant sd2iec firmware due to some ports being used differently (and the LEDs being reversed polarity). But if you look at the Shadowolf version of the board (which is missing the external oszillator, so just look at the port connections) you can easily identify the differences.

- The IEC-Bus uses different Pins.
- The LEDs use different Pins (and they pull against GND for shadowolf, but against Vcc on LarsP)
- The Device# and Disk Change jumpers/buttons use other Pins.
- And yes, it uses a voltage divider instead of FETs...

Quoted

5. Should the IEC leads for Shadowolf's board be connected to two IEC connectors (like inside 1541)?

As you wish. It's probably easier to work with both a Floppy and a sd2iec if you have two connectors installed.

Meine Bastelseite: C64&1541 - MMC/SD2IEC - C64DTV - AMIGA - Konsolen - etc
C64Links: Wiki DTVWiki RayCarlsen TechInfo Manuals BoardRevs Zimmers

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for(;;)

caT

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4

Wednesday, March 24th 2010, 3:55pm

Quoted from "PCXT"

There's a way to connect a PCF8563 RTC to I2C, as I think to mark file dates properly. Are there any schematics showing how to connect this?

You may have a look at this: FE3 schematic

It includes a SD2IEC with LarsP-Layout and RTC w. battery

petSD

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PCXT

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5

Wednesday, March 24th 2010, 10:12pm

Thanks for all answers ;-).
I'll consider AntaBaka's version, because it can be easily built on universal board (I have lots of them from recycling).

Thanks for(;

for this schematic. This is what I wanted about this clock.

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AntaBaka

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6

Wednesday, March 24th 2010, 10:19pm

No prob.

The schematic is on the same page you linked yourself

Just a bit further down, hehe...

Meine Bastelseite: C64&1541 - MMC/SD2IEC - C64DTV - AMIGA - Konsolen - etc
C64Links: Wiki DTVWiki RayCarlsen TechInfo Manuals BoardRevs Zimmers

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PCXT

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7

Friday, March 26th 2010, 8:49pm

One more thing - I read somewhere that Shadowolf's IEC circuits (with MOSFETs) are more compatible while working with many IEC devices. And I have some questions about them:
1. Is IEC_RESERVE pin (defined in config.h as IEC_SRQ) needed? In schematic, it's labelled like temporary.
2. About MOSFETs, because I don't know much about them - what are non-SMD alternatives to IRLML2402? Will MOSFET with higher power (non-SMDs usually are) be good?

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AntaBaka

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8

Friday, March 26th 2010, 9:39pm

Quoted from "PCXT"

One more thing - I read somewhere that Shadowolf's IEC circuits (with MOSFETs) are more compatible while working with many IEC devices.

I read that too, maybe Unseen can shed some light on this.
I never used more then two devices on the IEC bus so far.

Quoted

1. Is IEC_RESERVE pin (defined in config.h as IEC_SRQ) needed? In schematic, it's labelled like temporary.

No, not really.

Meine Bastelseite: C64&1541 - MMC/SD2IEC - C64DTV - AMIGA - Konsolen - etc
C64Links: Wiki DTVWiki RayCarlsen TechInfo Manuals BoardRevs Zimmers

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Unseen

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9

Friday, March 26th 2010, 10:04pm

Quoted from "PCXT"

One more thing - I read somewhere that Shadowolf's IEC circuits (with MOSFETs) are more compatible while working with many IEC devices.

With more than three or four original CBM drives (and probably other serial devices, although not any hardware that sd2iec runs on) connected to the serial bus the AVRs outputs are not strong enough to provide reliable signals on the bus - the additional MOSFETs of Shadowolf's design can pull "harder" on the lines and IIRC have been tested with up to 10 drives on the bus.

Quoted

1. Is IEC_RESERVE pin (defined in config.h as IEC_SRQ) needed? In schematic, it's labelled like temporary.

In theory it could be used for the C128's burst mode, but that is not implemented in sd2iec.

Quoted

2. About MOSFETs, because I don't know much about them - what are non-SMD alternatives to IRLML2402? Will MOSFET with higher power (non-SMDs usually are) be good?

Sorry, I have no clue about that - I'm primarily a software person.

	Quellcode
1 2 3	10 x=rnd(-1963):fori=1to81:y=rnd(1):next 20 forj=1to5:printchr$(rnd(1)16+70);:next 30 printint(rnd(1)328)-217

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suchy

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10

Friday, May 28th 2010, 11:57am

@ PCXT, use 3V LogicLevel NMOSFETS with very low Vgs(tsh).

My MMC/SD2IEC

LarsP Layout (THANKS AntaBaka) with ATMEGA644P DIP40

firmware: sd2iec-0.9.1-larsp-m644p.bin

I tested PCF8583: SDA-PC5, SCL-PC6, it works.

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suchy

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11

Thursday, February 24th 2011, 5:13pm

Quoted from "suchy"

My MMC/SD2IEC

New LINK

&

http://c64scene.pl/viewtopic.php?t=616

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AntaBaka

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