DS80C390_00 Datasheet, PDF (134/155 Pages) Dallas Semiconductor – High-Speed Microcontroller User’s Guide Supplement

Figure 16- 4 CRC Field
Data Field or
Control Field
DS80C390 High-Speed Microcontroller User’s Guide Supplement
CRC Field
ACK Field
CRC Sequence
CRC Delimiter
Acknowledge Field (ACK): (Standard and Extended Format)
The ACK Field is made up of two bits. The transmitting node will send two recessive bits in the ACK
field. The receiving nodes which have received the message and found the CRC Sequence to be correct
will reply by driving the ACK Slot with a dominant bit. The ACK Delimiter is always a recessive bit.
Figure 16- 5 Acknowledge Field
CRC Field
ACK Field End of Frame
ACK
Slot
ACK Delimiter
End of Frame: (Standard and Extended Format)
The End of Frame for both the Data and Remote Frame is established by the transmitter by sending seven
recessive bits.
Interframe Spacing (Intermission): (Standard and Extended Format)
Data Frames and Remote Frames are separated from preceding frames by three recessive bits termed the
Intermission. During the Intermission the only allowed signaling to the bus is by an Overload condition.
No node is allowed to start a message transmission of a Data or Remote Frame during this period. If no
node becomes active following the Interframe Space an indeterminate number of recessive bit times will
transpire in the Bus Idle condition until the next transmission of a new Data or Remote Frame by a node.
Figure 16- 6 Intermission
Frame
Interframe Space
Frame
Intermisson Bus Idle
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