at34c02b ATMEL Corporation, at34c02b Datasheet - Page 13

• Manufacturer Part Number: at34c02b
• Description: Two-wire Serial Eeprom With Permanent And Reversible Software Write Protect 2k 256 X 8
• Manufacturer: ATMEL Corporation

3417E–SEEPR–1/07
does not respond with a zero but does generate a following stop condition (see Figure
14 on page 14).
SEQUENTIAL READ: Sequential reads are initiated by either a current address read or
a random address read. After the microcontroller receives a data word, it responds with
an acknowledge. As long as the EEPROM receives an acknowledge, it will continue to
increment the data word address and serially clock out sequential data words. When the
memory address limit is reached, the data word address will “roll over” and the sequen-
tial read will continue. The sequential read operation is terminated when the
microcontroller does not respond with a zero but does generate a following stop condi-
tion (see Figure 15 on page 14).
PERMANENT WRITE PROTECT REGISTER (PSWP) STATUS: To find out if the regis-
ter has been programmed, the same procedure is used as to program the register
except that the R/W bit is set to 1. If the device sends an acknowledge, then the perma-
nent write protect register has not been programmed. Otherwise, it has been
programmed and the device is permanently write protected at the first half of the array.
Table 10. PSWP Status
REVERSIBLE WRITE PROTECT REGISTER(RSWP) STATUS: To find out if the regis-
ter has been programmed, the same procedure is used as to program the register
except that the R/W bit is set to 1. If the sends an device acknowledge, then the revers-
ible write protect register has not been programmed. Otherwise, it has been
programmed and the device is write protected (reversible) at the first half of the array.
Figure 10. Device Address
Figure 11. Byte Write
Command
Read PSWP
A2
A2
A1
A1
Pin
A0
A0
B7
0
B6
1
B5
1
Preamble
B4
0
B3
A2
B2
A1
B1
A0
RW
B0
1
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