AMIS-49587 Datasheet, PDF (39/59 Pages) ON Semiconductor – Power Line Carrier Modem

AMIS−49587
MEDIUM ACCESS CONTROL
DESCRIPTION
The local communication exchanges data with the MAC
sub−layer. These data (included into local frames) contain
information about the DLC frame transmission on the mains
(Initial credit, current credit, delta credit, local and
destination MAC addresses) and the data field. Other
information for transmission such as the Preamble, the Start
Sub−frame Delimiter, the Frame Indicator and the Frame
Check Sequence are directly managed by the MAC
sub−layer and the PHYsical layer. In case of transmission
from AMIS−49587 to the mains, if necessary, the MAC
sub−layer will separate the frame into one or several
sub−frame(s) (maximum 7 sub−frames). In case of frame
reception made up of several sub−frames, the AMIS−49587
will send back the complete frame (without Pre, SSD, FI,
FCS) to the local communication after the last sub−frame
reception and only if the frame is correct and dedicated for
this application.
THE COMMANDS AVAILABLE
MA_DATA_Request (Tag 51h)
Description: The MA_Data_Request is sent from the base micro local LLC sub−layer to the AMIS−49587 local MAC
sub−layer to request a DLC frame transmission. This request must be received by the AMIS−49587 in the time−slot preceding
the transmitting one.
Syntax:
Initiator
Base Micro
Master/Slave
Command (arguments)
MA_Data_Request (MAC_Frame)
Possible Response
MA_Data_Confirm (Transmission_Status)
Frame Format :
<STX> Length
< MA_Data_Request >
MAC_Frame
CHK
Table 36. DESCRIPTION OF THE MAC_FRAME FIELD
Field name
Length
Value
Initial Credit
Current Credit
Delta Credit
3 bits b7−b5
3 bits b4−b2
2 bits b1,b0
0h to 7h
0h to 7h
0h to 3h
Source Address
12 bits b23−b12
Not used
000h to FFFh
Destination Address
12 bits b11−b0
000h to FFFh
Pad length
1 byte
Not used
M_sdu
up to 242 bytes
Description
Initial Credit
Current Credit = Initial Credit
Delta Credit = Received Delta Credit (Slave) = 0 (Master)
Slave Mode (Filled by MAC layer)
Master Mode
Destination MAC address of the target station DLC
Filled by MAC layer
MAC service data unit
MA_DATA_Confirm (Tag 52h)
Description: The MA_DATA_Confirm is sent from AMIS−49587 to a base micro (SLAVE or MASTER) either as positive
acknowledgment when a MA_DATA_Request has successfully been transmitted by the physical layer, or as negative
acknowledgment when the transmission has been refused. The positive acknowledgment is sent after the frame transmission
on the mains and before the beginning of the repetition (if the credit is higher than zero). The Transmission_Status byte contains
a value corresponding at this positive or negative acknowledgment. The different values for the Transmission_Status field are
described in the Table 45: Transmission Status.
Syntax:
Initiator
AMIS−49587
Master/Slave
Command (arguments)
MA_Data_Confirm (Transmission_Status)
Possible Response
Frame Format :
<STX> Length
< MA_Data_Confirm >
Transmission_Status
CHK
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