Datasheet

25A512
DS22237C-page 8 Preliminary  2010-2011 Microchip Technology Inc.
Read Sequence
The device is selected by pulling CS low. The 8-bit
READ instruction is transmitted to the 25A512 followed
by the 16-bit address. After the correct READ instruction
and address are sent, the data stored in the memory at
the selected address is shifted out on the SO pin. The
data stored in the memory at the next address can be
read sequentially by continuing to provide clock pulses.
The internal Address Pointer is automatically incre-
mented to the next higher address after each byte of
data is shifted out. When the highest address is
reached (FFFFh), the address counter rolls over to
address 0000h allowing the read cycle to be continued
indefinitely. The READ instruction is terminated by rais-
ing the CS
pin (Figure 2-1).
FIGURE 2-1: READ SEQUENCE
SO
SI
SCK
CS
0 234567891011 21222324252627282930311
0100000115 14 13 12 210
76543210
Instruction 16-bit Address
Data Out
High-Impedance