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The full command sequence and flow chart for Chip Erase operation is provided on page 49 of the datasheet. Similarly, the command sequence for read command is explained on page 43. You can download our low level driver for parallel NOR flash devices from the following link and use it in your application.
Regarding wait time requirement after power on, I am looking into this query and shall get back to you on this shortly.
I would like to inform you that GL-N is not a new part and is not recommended for new designs. Please let me know if you have any more queries.
The minimum amount of time that you should wait after power on (tVCS) as mentioned in the datasheet on page 71 is 50us.
You can also find this parameter in the timing diagram for Chip/Sector Erase operation (Figure 15.6) on page 73 of the datasheet.