I have a logic analyzer coming in the mail, but thought I might ask for help here first.

I soldered the 25Q128 flash onto an adapter and wired it up to an Arduino UNO clone as you can see in the images below. I get nonsense data in the serial monitor. The 4 10k resistors are connected in parallel to GND and there are 4.7k resistors on the SCK, MISO, MOSI and CS lines. I am using the TestFlash sketch from the SPIMemory Arduino library by Marzogh. Could it be a bad soldering joint? Or am I missing something?

I used this as a guide also:



Here are some pictures and a diagram.





Fritzing diagram

  • 2
    That "guide" is bad. You don't want any resistors on MISO. Just connect it direct between the Arduino and the chip.
    – Majenko
    Commented Jan 23, 2021 at 17:48

1 Answer 1


You will be better to buy one of these from aliExpress. enter image description here

here's de pinout connections to an arduino:

  • Pin 1 - CS

  • Pin 2 - D0 (I/O1)

  • Pin 3 - VCC (I/O2)

  • Pin 4 - GND

  • Pin 5 - Di

  • Pin 6 - CLK

  • Pin 7 - VCC (I/O)

  • Pin 8 - VCC

this connection setup does not make use of the full data parallel async I/O, as you can see only I/O1 is connected to D0. This way has much slower data transfers.

  • what is "pin 1"? Uno TX pin?
    – Juraj
    Commented Oct 13, 2021 at 5:16
  • CS = chip select Commented Oct 13, 2021 at 7:09
  • 1
    I ask what are the pins on the left. Uno pins? you use the TX pin as CS?
    – Juraj
    Commented Oct 13, 2021 at 7:13
  • you can use any digital pin for CS Commented Oct 13, 2021 at 12:55

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