Datasheet

512
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
31.7.8.12 Frame Slot Mode
This mode is useful only for Master nodes. It respects the following rule: each frame slot shall be longer than or
equal to TFrame_Maximum.
If the Frame Slot Mode is enabled (FSDIS = 0) and a frame transfer has been completed, the TXRDY flag is set
again only after TFrame_Maximum delay, from the start of frame. So the Master node cannot send a new header if
the frame slot duration of the previous frame is inferior to TFrame_Maximum.
If the Frame Slot Mode is disabled (FDIS = 1) and a frame transfer has been completed, the TXRDY flag is set
again immediately.
The TFrame_Maximum is calculated as below:
If the Checksum is sent (CHKDIS = 0):
• THeader_Nominal = 34 x TBit
• TResponse_Nominal = 10 x (NData + 1) x TBit
• TFrame_Maximum = 1.4 x (THeader_Nominal + TResponse_Nominal + 1)
(Note:)
• TFrame_Maximum = 1.4 x (34 + 10 x (DLC + 1 + 1) + 1) x TBIT
• TFrame_Maximum = (77 + 14 x DLC) x TBIT
If the Checksum is not sent (CHKDIS = 1):
• THeader_Nominal = 34 x TBit
• TResponse_Nominal = 10 x NData x TBit
• TFrame_Maximum = 1.4 x (THeader_Nominal + TResponse_Nominal + 1
(Note:)
)
• TFrame_Maximum = 1.4 x (34 + 10 x (DLC + 1) + 1) x TBIT
• TFrame_Maximum = (63 + 14 x DLC) x TBIT
Note: The term “+1” leads to an integer result for TFrame_Max (LIN Specification 1.3)
Figure 31-45. Frame Slot Mode
Break
Synch
Protected
Identifier
Data N
Checksum
Header
Inter-
frame
space
Response
space
Frame
Frame slot = TFrame_Maximum
Response
TXRDY
Write
US_THR
Write
US_LINID
Data 1 Data 2 Data 3
Data3
Data N-1
Data N
Frame Slot Mode
Disabled
Frame Slot Mode
Enabled
LINTC
Data 1