MR25H256CDC EverSpin Technologies Inc, MR25H256CDC Datasheet - Page 8

• Manufacturer Part Number: MR25H256CDC
• Description: IC MRAM 256KBIT 40MHZ 8DFN
• Manufacturer: EverSpin Technologies Inc

Specifications of MR25H256CDC

• Format - Memory: RAM
• Memory Type: MRAM (Magnetoresistive RAM)
• Memory Size: 256K (32K x 8)
• Speed: 40MHz
• Interface: SPI Serial
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-VDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 819-1015

Everspin Technologies © 2010
Write Data Bytes (WRITE)
The Write Data Bytes (WRITE) command allows data bytes to be written starting at an address specified by
the 8-bit address. The data bytes are written sequentially in memory until the write operation is terminated
by bringing CS high. The entire memory can be written in a single command. The address counter will roll
over to 0000h when the address reaches the top of memory.
Unlike EEPROM or Flash Memory, MRAM can write data bytes continuously at its maximum rated clock
speed without write delays or data polling. Back to back WRITE commands to any random location in mem-
ory can be executed without write delay. MRAM is a random access memory rather than a page, sector, or
block organized memory so it is ideal for both program and data storage.
The WRITE command is entered by driving CS low, sending the command code, and then sequential write
data bytes. Writes continue as long as the memory is clocked. The command is terminated by bringing CS
high.
SPI COMMUNICATIONS PROTOCOL
SCK
SCK
CS
CS
SO
SO
SI
SI
7
40
0
0
6
41
0
1
5
42
0
2
Instruction (02h)
MSB
Data Byte 2
4
43
0
3
3
44
0
4
2
45
0
High Impedance
5
1
46
High Impedance
1
6
0
47
0
7
7
48
MSB
X
8
6
Figure 2.6 WRITE
49
X
9
5
50
Data Byte 3
X
10
4
51
16-Bit Address
8
3
52
3
2
28
53
Document Number: MR25H256 Rev. 2, 4/2010
2
1
29
54
1
0
30
55
0
31
MSB
MSB
7
7
32
6
6
32
5
5
32
Data Byte N
MR25H256
4
4
32
3
3
32
2
2
32
1
1
32
0
0
32
Mode 3
Mode 0