TSS461 ATMEL Corporation, TSS461 Datasheet - Page 45

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

Retries,
Rearbitrate and
Abort
Retries
4194C–AUTO–01/06
Retries and rearbitrate commands are located, in the Transmit Control Register and in the Com-
mand Register, respectively. An abort command is located in each channel register set, in the
Message Length & Status Register (base_address + 0x03). These three commands are avail-
able only when the TSS461E is producer.
Figure 25. Transmit Function
The purpose of retries feature is to provide, the capability of retrying a transmit request in case
of failure, when a node tries to reach another node, either on normal DATA frame or on REPLY
REQUEST frame.
The maximum of retries is programmable through MR[3:0] of the Transmit Control Register
(0x01). When a channel is enable – bit CHTx= 0 of Message Length & Status Register, a 4-bit
counter is loaded with MR[3:0]. At each attempt, this counter will be countdown. To 0, an IT TE
is set in the Interrupt Status Register (0x09), and the transmission is stopped.
MR[3:0] = 1 indicates 1 retry, hence 2 transmission attempts will be performed (see Table 4).
The number of retries performed, as well as the current channel number associated, can be
read in the Transmission Status Register (0x05).
The Last Error Status Register (0x07) informs about the trouble encountered:
retry counter
Decrement
current Ch.
Disable of
abort
yes
yes
(EOF+IFS= 12 Timeslots)
and wait for the end
load”Max - retries”
Select the lowest
Wait for bus free
Ch. number and
on current Ch.?
Transmit frame
Abort activated
Ch. Enabled in
Retry needed?
Abort required
on current Ch.
Xmit Mode?
rearbitrate?
Activate
yes
no
no
no
no
rearbitrate
TSS461E
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