ST93C06C ST Microelectronics, ST93C06C Datasheet - Page 9

• Manufacturer Part Number: ST93C06C
• Description: 256 bit 16 x 16 or 32 x 8 SERIAL MICROWIRE EEPROM
• Manufacturer: ST Microelectronics

Erase All
The Erase All instruction (ERAL) erases the whole
memory (all memory bits are set to ’1’). A dummy
address is input during the instruction transfer and
the erase is made in the same way as the ERASE
instruction. If the ST93C06 is still performing the
erase cycle, the Busy signal (Q = 0) will be returned
if S is driven high, and the ST93C06 will ignore any
data on the bus. When the erase cycle is com-
pleted, the Ready signal (Q = 1) will indicate (if S
is driven high) that the ST93C06 is ready to receive
a new instruction.
Write All
For correct operation, an ERAL instruction should
be executed before the WRAL instruction: the
WRAL instruction DOES NOT perform an automat-
ic erase before writing. The Write All instruction
(WRAL) writes the Data Input byte or word to all the
addresses of the memory. If the ST93C06 is still
performing the write cycle, the Busy signal (Q = 0)
will be returned if S is driven high, and the ST93C06
will ignore any data on the bus. When the write
cycle is completed, the Ready signal (Q = 1) will
indicate (if S is driven high) that the ST93C06 is
ready to receive a new instruction.
READY/BUSY Status
During every programming cycle (after a WRITE,
ERASE, WRAL or ERAL instruction) the Data Out-
put (Q) indicates the Ready/Busy status of the
Figure 9. ST93C06 Timing
S
D
C
Dummy Clock pulse
0
memory when the Chip Select (S) is driven High.
Once the ST93C06 is Ready, the Ready/Busy
status is available on the Data Output (Q) until a
new start bit is decoded or the Chip Select (S) is
brought Low.
COMMON I/O OPERATION
The Data Output (Q) and Data Input (D) signals can
be connected together, through a current limiting
resistor, to form a common, one wire data bus.
Some precautions must be taken when operating
the memory with this connection, mostly to prevent
a short circuit between the last entered address bit
(A0) and the first data bit output by Q. The reader
may also refer to the SGS-THOMSON application
note ”MICROWIRE EEPROM Common I/O Opera-
tion”.
DIFF ERENCES BETWEEN ST93C06 AND
ST93C06C
Each instruction of the ST93C06 requires an Addi-
tional Dummy clock pulse after the rising edge of
the Chip Select input (S) and before the START bit,
see Figure 9. When replacing the ST93C06 with
the ST93C06C in an application, it must be
checked that this Dummy Clock cycle DOES NOT
HAPPEN when D = 1: if it is so, this clock pulse will
latch an information which is decoded by the
ST93C06C as a START bit (see Figure 10) and the
following bits will be decoded with a shift of one bit.
START Bit
1
AI01334
ST93C06, ST93C06C
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