Winbond W25M512JVFIQ serial Flash
The Winbond W25M512JVFIQ is a stacked SPI Flash, meaning it consists of two seperate 256 MBit SPI Flashes. Both SPI Flashes share the same Pins and by default always Die #0 is selected for access. To select the second SPI Flash die #1 it is necessary to send a special command to the SPI Flash. After sending the command you can access die #1 similar to accessing die #0 before.
Selecting second Flash die of Winbond W25M512JVFIQ serial flash
The following initsteps show how to reconfigure the serial flash to select the second die of the stacked SPI Flash by sending the command "0xC2 0x01"
To select the first die #0 again send "0xC2 0x00" to the SPI Flash or reset the SPI Flash.