Possible to use W25Q128FVSG with only resistors and no level shifter?

is there a way to use w25q128FVSG with resistor(ONLY!) without use of level shifter or " Diode and reistor level shifter "

Yeah, you can use the “lite version” of the schematic.

I believe this should be exactly what you’re looking for although you will need a capacitor as well as a resistor.

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yeah, but this might damage the chip. I am giving 3.3v in VCC but the pro micro clone I am using uses a 4v voltage regulator so the pins give a max of 4v (I did not confirm if its 4v) out while the chip uses 0.004A of current so

(A - B) / C = 230 ohms

A = 4v ( pro micro output)

B = 3.08v (voltage I wanna put into all the other pins except VCC? and hold?

C = current drawn from the flash chip

But I don’t know if this will work because I only have 1 flash chip and I don’t wanna damage it

I think people use resistors to limit the voltage when using a ST7789 display and it also works with 3.3v not 5v so I think it might work

You can use a voltage divider on the output pin of the controller. But you need a regulator to supply the flash chip with that same voltage.

It is more important to keep signal voltage and power supply at the same level than it is to worry about 1 volt too much.

If you really do smoke it from just 4 volts let me know I’ll send you a replacement for free I have several hundred sitting in the shelf not doing anything. :slight_smile:

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If you are supplying 3.3V to VCC then the chip’s outputs will be a little lower than 3.3V. What you are likely thinking of is if you power the pro micro from usb there’s a diode drop so it’s IO falls somewhere around 4V. In either case VCC and IO voltage will always be very close to eachother. In the end the IO can never (normally) output a voltage higher than the chip’s VCC because the IO is a totem cmos output driven from VCC.


I made a schematic that I will use but I am not too sure about the connections

do I need a capacitor between GND and VCC also do I need to put a 10k resistor between VCC and cs and do I need to connect WP to vcc. Btw all the resistors are 220 ohms

I also have another question. if I program the board separately using an Arduino mega, then do I need the programmer(Arduino mega) again to program the w25q128fvsg flash chip

i did not have that in mind in fact I did not even know that there was a diode drop

Traces on the same layer cannot cross or they will short together. As for a cap between vcc and gnd, it’s good practice to place as close as possible near the power pins of the ic.

I just made it as a way to see what the connections might be like i am using a perf board to actually solder everything

Thx, also do I need to put a 10k resistor between cs and vcc?

Sorry, so for the arduclone I made I didn’t have a pullup for cs and I directly connected wp to vcc and it works for me but that may not necessarily be best practice.

Why are you using series resistors? How many other circuits have you built before? I wouldn’t recommend Arduboy to be your first try, it’s recommended for intermediate users. But you’ve got the cad software, so I can see you’re on a good start.

But based on the questions you are asking I wonder if you might find some other projects to start on first that can build a foundation for better understanding arduboy.

Either way I wish you luck, but it seems like you’re focusing on moving quickly instead of learning well.

I have made quite alot of Arduino and esp32 projects but arduboy is just quite interesting I have never used flash memory so I do not understand this well, as I a budget for projects and just spend last of it on flash memory so I cant get a levelshifter or a 1N1418 diode

Ok well, I think the series resistors are not necessary, they won’t harm anything either, I don’t think. As long as they aren’t too large value.

i am using 220 ohm resistors.