CAT25080 Datasheet, PDF (9/16 Pages) Catalyst Semiconductor – 8-Kb and 16-Kb SPI Serial CMOS EEPROM

CAT25080, CAT25160
READ OPERATIONS
Read from Memory Array
To read from memory, the host sends a READ instruction
followed by a 16−bit address (see Table 11 for the number
of significant address bits).
After receiving the last address bit, the CAT25080/160
will respond by shifting out data on the SO pin (as shown in
Figure 9). Sequentially stored data can be read out by simply
continuing to run the clock. The internal address pointer is
automatically incremented to the next higher address as data
is shifted out. After reaching the highest memory address,
the address counter “rolls over” to the lowest memory
address, and the read cycle can be continued indefinitely.
The read operation is terminated by taking CS high.
Read Status Register
To read the status register, the host simply sends a RDSR
command. After receiving the last bit of the command, the
CAT25080/160 will shift out the contents of the status
register on the SO pin (Figure 10). The status register may
be read at any time, including during an internal write cycle.
While the internal write cycle is in progress, the RDSR
command will output the RDY (Ready) bit status only (i.e.,
data out = FFh).
CS
SCK
0 1 2 3 4 5 6 7 8 9 10 20 21 22 23 24 25 26 27 28 29 30
OPCODE
BYTE ADDRESS*
SI
0 0 0 0 0 0 1 1 ^AN
A₀
SO
Dashed Line = mode (1, 1)
HIGH IMPEDANCE
* Please check the Byte Address Table (Table 11)
DATA OUT
765432 10
MSB
Figure 9. READ Timing
CS
SCK
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14
OPCODE
SI
0
0
0
0
0
1
01
HIGH IMPEDANCE
SO
Dashed Line = mode (1, 1)
DATA OUT
7
6
5
4
32
10
MSB
Figure 10. RDSR Timing
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