M95320-R View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'M95320-R' PDF : 48 Pages View PDF
M95320-W M95320-R M95320-DR
Instructions
When the highest address is reached, the address counter rolls over to zero, allowing the
Read cycle to be continued indefinitely. The whole memory can, therefore, be read with a
single READ instruction.
The Read cycle is terminated by driving Chip Select (S) high. The rising edge of the Chip
Select (S) signal can occur at any time during the cycle.
The instruction is not accepted, and is not executed, if a Write cycle is currently in progress.
6.6
Write to Memory Array (WRITE)
As shown in Figure 12, to send this instruction to the device, Chip Select (S) is first driven
low. The bits of the instruction byte, address byte, and at least one data byte are then shifted
in, on Serial Data Input (D).
The instruction is terminated by driving Chip Select (S) high at a byte boundary of the input
data. The self-timed Write cycle, triggered by the Chip Select (S) rising edge, continues for a
period tW (as specified in AC characteristics in Section 9: DC and AC parameters), at the
end of which the Write in Progress (WIP) bit is reset to 0.
Figure 12. Byte Write (WRITE) sequence
S
0 1 2 3 4 5 6 7 8 9 10 20 21 22 23 24 25 26 27 28 29 30 31
C
Instruction
16-Bit Address
Data Byte
D
15 14 13 3 2 1 0 7 6 5 4 3 2 1 0
High Impedance
Q
AI01795D
1. Depending on the memory size, as shown in Table 5, the most significant address bits are Don’t Care.
In the case of Figure 12, Chip Select (S) is driven high after the eighth bit of the data byte
has been latched in, indicating that the instruction is being used to write a single byte.
However, if Chip Select (S) continues to be driven low, as shown in Figure 13, the next byte
of input data is shifted in, so that more than a single byte, starting from the given address
towards the end of the same page, can be written in a single internal Write cycle.
Each time a new data byte is shifted in, the least significant bits of the internal address
counter are incremented. If the number of data bytes sent to the device exceeds the page
boundary, the internal address counter rolls over to the beginning of the page, and the
previous data there are overwritten with the incoming data. (The page size of these devices
is 32 bytes).
Doc ID 5711 Rev 14
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