Quad-Serial Configuration (EPCQ) Devices Datasheet

ID 683078
Date 1/23/2020
Document Table of Contents

1.7.5. Fast Read Operation (0Bh)

When you execute the fast read operation, you first shift in the fast read operation code, followed by a 3-byte addressing mode (A[23..0]) or a 4-byte addressing mode (A[31..0]), and dummy clock cycle(s) with each bit being latched-in during the rising edge of the DCLK signal. Then, the memory contents at that address is shifted out on DATA1 with each bit being shifted out at a maximum frequency of 100 MHz during the falling edge of the DCLK signal.

Figure 11. Fast Read Operation Timing DiagramTo access the entire EPCQ256 or EPCQ512/A memory, use 4-byte addressing mode. In the 4-byte addressing mode, the address width is 32-bit address.

The first byte address can be at any location. The device automatically increases the address to the next higher address after shifting out each byte of data. Therefore, the device can read the whole memory with a single fast read operation. When the device reaches the highest address, the address counter restarts at 0x000000, allowing the read sequence to continue indefinitely.

You can terminate the fast read operation by driving the nCS signal high at any time during data output. If the fast read operation is shifted in while an erase, program, or write cycle is in progress, the operation is not executed and does not affect the erase, program, or write cycle in progress.