How do I switch between the 3-byte address and 4-byte address read/ program/ erase operations on Cypress's 256 Mbit SPI Flash device? - KBA203738

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Question:

How do I switch between the 3-byte address and 4-byte address read/ program/ erase operations on Cypress's 256 Mbit SPI Flash device?

 

Answer:

The Cypress 256 Mbit SPI Flash device (and higher density SPI Flash) provides commands which can use 3-byte and 4-byte addresses. This is done by setting bit0 and bit7 of the Bank Address Register accordingly. When a 3-byte address is used, bit0 = 0 and bit7 = 0 should be set in the Bank Address Register (power-up default value) to address the lower half of the memory locations. To address the upper half of the memory locations, bit0 = 1 and bit7= 0 should be set in the Bank Address Register. When a 4-byte address is used, bit7 of the Bank Address Register should be set to 1. Bit0 is a "Don't care."