Instructions
M93C86, M93C76, M93C66, M93C56, M93C46
5.1
Read Data from Memory
The Read Data from Memory (READ) instruction outputs data on Serial Data Output (Q).
When the instruction is received, the op-code and address are decoded, and the data from
the memory is transferred to an output shift register. A dummy 0 bit is output first, followed
by the 8-bit byte or 16-bit word, with the most significant bit first. Output data changes are
triggered by the rising edge of Serial Clock (C). The M93Cx6 automatically increments the
internal address register and clocks out the next byte (or word) as long as the Chip Select
Input (S) is held High. In this case, the dummy 0 bit is
not
output between bytes (or words)
and a continuous stream of data can be read.
5.2
Write Enable and Write Disable
The Write Enable (WEN) instruction enables the future execution of erase or write
instructions, and the Write Disable (WDS) instruction disables it. When power is first
applied, the M93Cx6 initializes itself so that erase and write instructions are disabled. After
an Write Enable (WEN) instruction has been executed, erasing and writing remains enabled
until an Write Disable (WDS) instruction is executed, or until V
CC
falls below the power-on
reset threshold voltage. To protect the memory contents from accidental corruption, it is
advisable to issue the Write Disable (WDS) instruction after every write cycle. The Read
Data from Memory (READ) instruction is not affected by the Write Enable (WEN) or Write
Disable (WDS) instructions.
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STMICROELECTRONICS [ STMICROELECTRONICS ]
