m24lr64-r STMicroelectronics, m24lr64-r Datasheet - Page 57

• Manufacturer Part Number: m24lr64-r
• Description: 64 Kbit Eeprom With Password Protection & Dual Interface 400 Khz I?c Serial Bus & Iso 15693 Rf Protocol At 13.56 Mhz
• Manufacturer: STMicroelectronics

M24LR64-R
16
M24LR64-R protocol description
The transmission protocol (or simply protocol) defines the mechanism used to exchange
instructions and data between the VCD and the M24LR64-R, in both directions. It is based
on the concept of “VCD talks first”.
This means that an M24LR64-R will not start transmitting unless it has received and
properly decoded an instruction sent by the VCD. The protocol is based on an exchange of:
●
●
Each request and each response are contained in a frame. The frame delimiters (SOF,
EOF) are described in
Each request consists of:
●
●
●
●
●
●
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Each response consists of:
●
●
●
●
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The protocol is bit-oriented. The number of bits transmitted in a frame is a multiple of eight
(8), that is an integer number of bytes.
A single-byte field is transmitted least significant bit (LSBit) first. A multiple-byte field is
transmitted least significant byte (LSByte) first, each byte is transmitted least significant bit
(LSBit) first.
The setting of the flags indicates the presence of the optional fields. When the flag is set (to
one), the field is present. When the flag is reset (to zero), the field is absent.
Table 20.
Table 21.
Request SOF Request_flags
Response
SOF
a request from the VCD to the M24LR64-R
a response from the M24LR64-R to the VCD
a request SOF (see
flags
a command code
parameters, depending on the command
application data
a 2-byte CRC
a request EOF (see
an answer SOF (see
flags
parameters, depending on the command
application data
a 2-byte CRC
an answer EOF (see
Response_flags
VCD request frame format
M24LR64-R Response frame format
Section 12: M24LR64-R to VCD
Figure 20
Figure
Figure 35
Figure 41
Doc ID 15170 Rev 9
Parameters
Command
22)
code
and
to
to
Figure
Figure
Figure
Parameters
40)
46)
21)
Data
frames.
M24LR64-R protocol description
Data
2-byte CRC
2-byte CRC
Response
Request
EOF
EOF
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