Hacking EZ-Flash Omega feature request: save indicator

imax9000 · May 24, 2021

Can we please get a first-class save indicator LED? Without it I get unnecessarily anxious about saving: did I wait long enough already to turn off safely? How about now? Maybe now? Sure it's safe now, right? right?

I don't mind soldering, however attaching the LED to SD card interface directly doesn't exactly inspire confidence that if LED is off then filesystem is in a consistent state. If there is a spare accessible pin on the FPGA that (with a firmware update) can drive an LED to turn it on before saving and turn it off afterwards - that would be awesome!

kiddejig · May 24, 2021

I have modded my Omega with a LED and I haven't had any problems yet.

Link to my thread:
https://gbatemp.net/threads/modded-ez-flash-omega-sd-activity-led.586869/

ghjfdtg · May 24, 2021

I would recommend driving the LED using a mosfet instead. That puts much less load on the data lines which are not intended for switching LEDs and data transfer at the same time. You are risking your data even if it appears to work fine.

imax9000 · May 24, 2021

kiddejig said:
I have modded my Omega with a LED and I haven't had any problems yet.

Yeah, I've seen your thread and Makho's video and find it not very satisfactory. Even aside from electrical interference, a finished write operation (and a LED being off) doesn't mean, in general case, that a) all of the save file was written and b) that all write operation required to make the filesystem consistent are finished too.

That's why I'd like to have signals from the same code that does the saving: "hey, I'm about to start saving, turn the LED on" and "okay, all writes committed and SD card reported success, turn the LED off"

kiddejig · May 25, 2021

ghjfdtg said:
I would recommend driving the LED using a mosfet instead. That puts much less load on the data lines which are not intended for switching LEDs and data transfer at the same time. You are risking your data even if it appears to work fine.

Interesting, you might be right about that. I'll let you guys know if I run into problems with corrupted files or anything. For now, I'm quite happy with my mod and I find it very useful seeing the LED blink and knowing the SD is being accessed.

imax9000 said:
Yeah, I've seen your thread and Makho's video and find it not very satisfactory. Even aside from electrical interference, a finished write operation (and a LED being off) doesn't mean, in general case, that a) all of the save file was written and b) that all write operation required to make the filesystem consistent are finished too.

That's why I'd like to have signals from the same code that does the saving: "hey, I'm about to start saving, turn the LED on" and "okay, all writes committed and SD card reported success, turn the LED off"

Fair enough, It is an interesting idea but I'm not so sure EZ-Flash are going to add features like this to the older version of the Omega flashcard. That is if there are even unused I/O pins accessible with a solder pad on the PCB. And if I'm not mistaken they have added an SD LED to the latest Omega Definitive Edition. So they have moved on for innovations to the later model.

imax9000 · May 25, 2021

kiddejig said:
Fair enough, It is an interesting idea but I'm not so sure EZ-Flash are going to add features like this to the older version of the Omega flashcard. That is if there are even unused I/O pins accessible with a solder pad on the PCB. And if I'm not mistaken they have added an SD LED to the latest Omega Definitive Edition. So they have moved on for innovations to the later model.

Damn, that'd be a shame

And it seems decompiling FPGA PROM blob isn't going to be easy too

skins4thewin · May 29, 2021

ghjfdtg said:
I would recommend driving the LED using a mosfet instead. That puts much less load on the data lines which are not intended for switching LEDs and data transfer at the same time. You are risking your data even if it appears to work fine.

How would you go about doing that? Where would you power it from? Would maybe using a higher value resistor make it a bit safer? Was thinking of using a 10k resistor if I were to do this and also far less wire than what Mahko used. That wasn't the best soldering job either. Would also just use a regular LED bulb, not a surface mount one.

imax9000 · May 29, 2021

skins4thewin said:
Where would you power it from?

I know an answer to this one: there are +5V and GND rails on the cartridge connector, and they're accessible as JTAG "+" and "-" on the back of Omega PCB.

Edit: it's 3.3V for GBA cartridges, but you get the point.

Hacking EZ-Flash Omega feature request: save indicator

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