A flash memory controller on a PCIE bus controls flash-memory modules on a flash bus. The flash-memory modules are plane-interleaved using interleaved bits extracted from the lowest bits of the logical block index. These plane-interleave bits are split into a LSB and a MSB, with middle physical block bits between the LSB and MSB. A physical sequential address counter generates a physical block number by incrementing the plane-interleave bits before the middle physical block bits, and then relocating the MSB to above the middle physical block bits. This causes blocks to be accessed in a low-high sequence of 0, 1, 4096, 4097, 2, 3, 4098, 4099, etc. in the four planes of flash memory. A RAM physical page valid table tracks valid pages in the four planes, while a RAM mapping table stores the plane, block, and page addresses for logical sectors generated by the physical sequential address counter.