TSS461 ATMEL Corporation, TSS461 Datasheet - Page 41

• Manufacturer Part Number: TSS461
• Description: VAN Data Link Controller
• Manufacturer: ATMEL Corporation

Figure 24. Message Status Updating
Message Data (String Pointed by: Message Pointer Register + 1)
4194C–AUTO–01/06
P: Producer
(*) After IT ROK or RNOK. In case of IT RE, the values can be erroneous.
Data Frame
Data Frame
Frame Type
Immediate
Immediate
Deferred
Deferred
Reply
Reply
Reply
Reply
DATA0 is the first received (or transmitted) byte, DATAn is the last one.
Notes:
1. If the length reserved (in the message length & status register) for an incoming frame is 2
2. The Mailbox RAM area is a circular buffer. The next location after 0xFF is 0x80.
Node x
I, C
I, C
I, P
bytes greater or more, the TSS461E will write the 2 bytes of the CRC field in the message
string just after DATAn.
Because the VAN frame does not contain a message length, the only way for the component
to know the length of the DATA field is either the message length register value, or the EOD
field detection. When the reserved length is too large, at the moment when it detects the EOD,
the TSS461E has already written the 2 bytes of the CRC field, considering these bytes as nor-
mal DATA.
C
P
P
- - -
7
I: Initiator
Commu-
nication
- - -
6
Node A
C: Consumer
I, P
I, C
I, C
- - -
5
C
P
P
RAK
RAK
RAK
RAK
RAK
Message Status on Node A after IT(*)
- - -
4
RNW
RNW
RNW
RNW
RNW
DATAn
DATA0
previous values
- - -
3
RTR
RTR
RTR
RTR
RTR
previous
previous
length
length
length
- - -
value
value
2
-- - -
TSS461E
1
- - -
0
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