I fabricated the PCB by combining STM32F769BI + IS42S32800D-6TLI SDRAM.
The circuit only changed the package type, and the circuit of the 769-EVAL board remained the same.
The firmware did the same.
However, SDRAM does not seem to work at all.
SDRAM initialization itself does not seem to be.
When observing the waveform with an oscilloscope, the address and other control signals were observed with normal waveforms.
However, the signal on the data bus looks like a triangle.
I want to know what the problem is.
EVAL-B / D shows a square wave when I watch a waveform, but my board has a triangular waveform, not a square wave.
The voltage should be 3.3V but it is about 0.8V.
Control signals...
but Data bus signal is...
The above figure shows that 1 is written on the data bus and reading is repeated.
As you can see in the picture,
In EVAl, a square wave came out, but on my board, it came out like a triangle wave.
The clock frequency or other signal is normal, but it seems that the data bus is not initialized due to these signals.
Can you see what's wrong?
