AT34C02C-TH-T View Datasheet(PDF) - Atmel Corporation
Part Name
Description
MFG CO.
AT34C02C-TH-T
Atmel Corporation
'AT34C02C-TH-T' PDF : 25 Pages View PDF
WP Connected to Vcc
Set PSWP
W
Programmed
X
Set PSWP
W
Not Programmed
X
Read
RSWP
R
Read
RSWP
R
X
Programmed
X
Not Programmed
Set RSWP
W
X
Programmed
Set RSWP
W
X
Not Programmed
Clear
RSWP
W
Programmed
X
Clear
RSWP
W
Not Programmed
X
No ACK
ACK
No ACK
ACK
No ACK
ACK
No ACK
ACK
STOP - Indicates permanent write protect register is
programmed
Cannot program write protect registers
STOP - Indicates reversible write protect register is
programmed
Read out data don't care. Indicates RSWP register is
not programmed
STOP - Indicates reversible write protect register is
programmed
Cannot program write protect registers
STOP - Indicates permanent write protect register is
programmed
Cannot write to write protect registers
8. Read Operations
Read operations are initiated the same way as write operations with the exception that the
read/write select bit in the device address word is set to one. There are three read operations:
current address read, random address read and sequential read.
CURRENT ADDRESS READ: The internal data word address counter maintains the last
address accessed during the last read or write operation, incremented by one. This address
stays valid between operations as long as the chip power is maintained. The address “roll over”
during read is from the last byte of the last memory page to the first byte of the first page.
Once the device address with the read/write select bit set to one is clocked in and acknowledged
by the EEPROM, the current address data word is serially clocked out. To end the command,
the microcontroller does not respond with an input zero but does generate a following stop con-
dition (see Figure 8-3 on page 14).
RANDOM READ: A random read requires a “dummy” byte write sequence to load in the data
word address. Once the device address word and data word address are clocked in and
acknowledged by the EEPROM, the microcontroller must generate another start condition. The
microcontroller now initiates a current address read by sending a device address with the
read/write select bit high. The EEPROM acknowledges the device address and serially clocks
out the data word. To end the command, the microcontroller does not respond with a zero but
does generate a following stop condition (see Figure 8-4 on page 14).
SEQUENTIAL READ: Sequential reads are initiated by either a current address read or a ran-
dom 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 sequential read will continue. The
sequential read operation is terminated when the microcontroller does not respond with a zero
but does generate a following stop condition (see Figure 8-5 on page 14).
12 AT34C02C
5185D–SEEPR–1/08
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