M14C64 Datasheet, PDF (5/14 Pages) STMicroelectronics – Memory Card IC 64/32 Kbit Serial I²C Bus EEPROM

M14C64, M14C32
the seven bits are fixed at 1010000b (A0h), as
shown in Table 5.
The 8^th bit is the read or write bit (RW). This bit is
set to ‘1’ for read and ‘0’ for write operations. If a
match occurs on the Device Select Code, the cor-
responding memory gives an acknowledgment on
the SDA bus during the 9^th bit time. If the memory
does not match the Device Select code, it will de-
select itself from the bus, and go into stand-by
mode.
Each data byte in the memory has a 16-bit (two
byte wide) address. The Most Significant Byte (Ta-
ble 3) is sent first, followed by the Least significant
Byte (Table 4). Bits b15 to b0 form the address of
the byte in memory. Bits b15 to b13 are treated as
a Don’t Care bit on the M14C64 memory. Bits b15
to b12 are treated as Don’t Care bits on the
M14C32 memory.
Write Operations
Following a START condition the master sends a
Device Select code with the RW bit set to ’0’, as
Figure 6. Write Mode Sequences with WC=1
shown in Table 6. The memory acknowledges it
and waits for two bytes of address, which provides
access to the memory area. After receipt of each
byte address, the memory again responds with an
acknowledge and waits for the data byte. Writing
in the memory may be inhibited if input pin WC is
taken high.
Any write command with WC=1 (during a period of
time from the START condition until the end of the
two bytes address) will not modify the memory
content and will NOT be acknowledged on data
bytes, as shown in Figure 6.
Byte Write
In the Byte Write mode, after the Device Select
code and the address, the master sends one data
byte. If the addressed location is write protected by
the WC pin, the memory replies with a NoACK,
and the location is not modified. If, instead, the WC
pin has been held at 0, as shown in Figure 7, the
memory replies with an ACK. The master termi-
nates the transfer by generating a STOP condi-
tion.
WC
BYTE WRITE
ACK
ACK
ACK
NO ACK
DEV SEL
BYTE ADDR BYTE ADDR
DATA IN
R/W
WC
PAGE WRITE
WC (cont'd)
PAGE WRITE
(cont'd)
ACK
ACK
ACK
NO ACK
DEV SEL
BYTE ADDR BYTE ADDR DATA IN 1
DATA IN 2
R/W
NO ACK
NO ACK
DATA IN N
AI01120B
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