STMicroelectronics M93C66-WMN6P Memory IC M93C66-WMN6P Data Sheet
Product codes
M93C66-WMN6P
Clock pulse counter
M93C86-x M93C76-R M93C66-x M93C56-x M93C46-x
DocID4997 Rev 15
8
Clock pulse counter
In a noisy environment, the number of pulses received on Serial Clock (C) may be greater
than the number delivered by the master (the microcontroller). This can lead to a
misalignment of the instruction of one or more bits (as shown in
than the number delivered by the master (the microcontroller). This can lead to a
misalignment of the instruction of one or more bits (as shown in
) and may lead to
the writing of erroneous data at an erroneous address.
To avoid this problem, the M93Cx6 has an on-chip counter that counts the clock pulses from
the start bit until the falling edge of the Chip Select Input (S). If the number of clock pulses
received is not the number expected, the WRITE, ERASE, ERAL or WRAL instruction is
aborted, and the contents of the memory are not modified.
the start bit until the falling edge of the Chip Select Input (S). If the number of clock pulses
received is not the number expected, the WRITE, ERASE, ERAL or WRAL instruction is
aborted, and the contents of the memory are not modified.
The number of clock cycles expected for each instruction, and for each member of the
M93Cx6 family, are summarized in
M93Cx6 family, are summarized in
. For example, a Write Data to Memory (WRITE)
instruction on the M93C56 (or M93C66) expects 20 clock cycles (for the x8 organization)
from the start bit to the falling edge of Chip Select Input (S). That is:
from the start bit to the falling edge of Chip Select Input (S). That is:
1 Start bit
+ 2 Op-code bits
+ 9 Address bits
+ 8 Data bits
+ 2 Op-code bits
+ 9 Address bits
+ 8 Data bits
Figure 8. Write sequence with one clock glitch
AI01395
S
An-1
C
D
WRITE
START
D0
"1"
"0"
An
Glitch
An-2
ADDRESS AND DATA
ARE SHIFTED BY ONE BIT