CY8CPLC20(2009) データシートの表示（PDF） - Cypress Semiconductor
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CY8CPLC20 Datasheet PDF : 44 Pages
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CY8CPLC20
Table 1-1. Powerline Transceiver (PLT) Packet Structure
Byte
Offset
Bit Offset
7 65
4
3
2
1
0
0x00 SA DA Type Service RSVD RSVD Response RSVD
Type
Type
0x01
Destination Address
(8-Bit Logical, 16-Bit Extended Logical or 64-Bit Physical)
0x02
Source Address
(8-Bit Logical, 16-Bit Extended Logical or 64-Bit Physical)
0x03
Command
0x04
RSVD
Payload Length
0x05
0x06
Seq Num
Powerline Packet Header CRC
Payload (0 to 31 Bytes)
Powerline Transceiver Packet CRC
1.3.3 Packet Header
The packet header contains the first 6 bytes of the packet when
1-byte logical addressing is used. When 8-byte physical
addressing is used, the source and destination addresses each
contain 8 bytes. In this case, the header can consist of a
maximum of 20 bytes. Unused fields marked RSVD are for future
expansion and are transmitted as bit 0. Table 1-2 describes the
PLT packet header fields in detail.
Table 1-2. Powerline Transceiver (PLT) Packet Header
Field
Name
SA Type
DA Type
Service
Type
Response
Seq Num
Header
CRC
No. of
Bits
Tag
Description
1 Source
0 – Logical Addressing
Address Type 1 – Physical Addressing
2 Destination 00 – Logical Addressing
Address Type 01 – Group Addressing
10 – Physical Addressing
11 – Invalid
1
0 – Unacknowledged Messaging
1 – Acknowledged Messaging
1 Response
0 - Not an acknowledgement or
response packet
1 - Acknowledgement or response
packet
4 Sequence
Number
4-bit unique identifier for each
packet between source and desti-
nation.
4
4-bit CRC value. This enables the
receiver to suspend receiving the
rest of the packet if its header is
corrupted
1.3.4 Payload
The packet payload has a length of 0 to 31 bytes. Payload
content is user defined and can be read or written through I2C.
1.3.5 Packet CRC
The last byte of the packet is an 8-bit CRC value used to check
packet data integrity. This CRC calculation includes the header
and payload portions of the packet and is in addition to the
powerline packet header CRC.
1.3.6 Sequence Numbering
The sequence number is increased for every new unique packet
transmitted. If in acknowledged mode and an acknowledgment
is not received for a given packet, that packet is re-transmitted
(if TX_Retry > 0) with the same sequence number. If in
unacknowledged mode, the packet is transmitted (TX_Retry + 1)
times with the same sequence number.
If the receiver receives consecutive packets from the same
source address with the same sequence number and packet
CRC, it does not notify the host of the reception of the duplicate
packet. If in acknowledged mode, it still sends an acknowl-
edgment so that the transmitter knows that the packet was
received.
1.3.7 Addressing
The CY8CPLC20 has three modes of addressing:
■ Logical addressing: Every CY8CPLC20 node can have either
a 8-bit logical address or a 16-bit logical address. The logical
address of the PLC Node is set by the local application or by
a remote node on the Powerline.
■ Physical addressing: Every CY8CPLC20 has a unique 64-bit
physical address.
■ Group addressing: This is explained in the next section.
1.3.8 Group Membership
Group membership enables the user to multicast messages to
select groups. The CY8CPLC20 supports two types of group
addressing:
■ Single Group Membership – The network protocol supports up
to 256 different groups on the network in this mode. In this
mode, each PLC node can only be part of a single group. For
example, multiple PLC nodes can be part of Group 131.
■ Multiple Group Membership – The network protocol supports
eight different groups in this mode and each PLC node can be
a part of multiple groups. For example, a single PLC node can
be a part of Group 3, Group 4, and Group 7 at the same time.
Both these membership modes can also be used together for
group membership. For example, a single PLC node can be a
part of Group 131 and also multiple groups such as Group 3,
Group 4, and Group 7.
The group membership ID for broadcasting messages to all
nodes in the network is 0x00.
The service type is always set to Unacknowledgment Mode in
Group Addressing Mode. This is to avoid acknowledgment
flooding on the powerline during multicast.
1.3.9 Remote Commands
In addition to sending normal data over the Powerline, the
CY8CPLC10 can also send (and request) control information to
(and from) another node on the network. The type of remote
command to transmit is set by the TX_CommandID register and
when received, is stored in the RX_CommandID register.
When a control command (Command ID = 0x01-0x08 and
0x0C-0x0F) is received, the protocol automatically processes
the packet (if Lock_Configuration is '0'), responds to the initiator,
and notifies the host of the successful transmission and
reception.
Document Number: 001-48325 Rev. *E
Page 4 of 44
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