flash SI has no signal

[wen]

I use spi0 to connect a flash GD25VQ16C.I send a Read Status Register Command 05,but there is no so signal.

[Werner Johansson]

The main gotcha with those flash parts is that they need #HOLD pulled high (some devices have built-in pull-ups, some don't). If #HOLD isn't pulled high the chip will not respond at all in single-bit mode.