st93c46a STMicroelectronics, st93c46a Datasheet - Page 8

• Manufacturer Part Number: st93c46a
• Description: 1k 64 X 16 Or 128 X 8 Serial Microwire Eeprom
• Manufacturer: STMicroelectronics

ST93C46A/46C/46T, ST93C47C/47T
INSTRUCTIONS (cont’d)
(Q = 0) will be returned if S is driven high, and the
ST93C46 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 ST93C46
is ready to receive a new instruction.
The Write instruction includes an automatic Erase
cycle before writing the data, it is therefore unnec-
essary to execute an Erase instruction before a
Write instruction execution.
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 above. If the ST93C46 is still performing
the write cycle, the Busy signal (Q = 0) will be
returned if S is driven high, and the ST93C46 will
Figure 7. ERASE, ERAL Sequences
Notes: 1. An: n = 5 for x16 org. and 6 for x8 org.
8/13
2. Xn: n = 3 for x16 org. and 4 for x8 org.
ERASE
ERASE
ALL
S
D
Q
S
D
Q
1 1
1
CODE
CODE
OP
0
OP
1
0
1
An
0
ADDR
ADDR
Xn X0
A0
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 ST93C46 is ready to
receive a new instruction.
Write All
For correct operation, an ERAL instruction should
be executed before the WRAL instruction.
The Write All instruction (WRAL) writes the Data
Input byte or word to all the addresses of the
memory. In the WRAL instruction, NO automatic
erase is made so all bytes/words must be erased
before the WRAL instruction. If the ST93C46 is still
performing the write cycle, the Busy signal (Q = 0)
will be returned if S is driven high, and the ST93C46
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 ST93C46 is
ready to receive a new instruction.
BUSY
BUSY
STATUS
STATUS
CHECK
CHECK
READY
READY
AI00879B