Motorola MC68824 User Manual page 49

II
the OFFLINE command may be given safely. The coding for this command is F8 and its format
is shown below:
WARNING
The free FD and BD pool pointers (see. SECTION 4 BUFFER STRUCTURES) may be
incorrect after issuing the OFFLINE command if any data frame was received since they
were last initialized. They must be reinitialized (SET TWO WORDS command) before
giving the IDLE or RECEIVE TEST command.
3.2.4 IDLE Command
The IDLE command causes the TBC to go from OFFLINE to the IDLE state. The IDLE command
must only be given when the TBC is in the OFFLINE state (i.e., not in_ring). The free frame
descriptor and free buffer descriptor pools should be initialized before giving this command. The
IDLE command is used, for example, after initialization, testing, or physical management.
The IDLE command causes the TBC to:
Clear any_send_pending (802.4 boolean),
Reset the receive and transmit machines,
Enable the receive machine,
Set noise expected (see 2.2.13 STATISTICS),
Zero the lasLtoken_rotation_timer (TRT) variable located in the private area,
Zero the internal token_rotation_timer (TRT) counter,
Set the no_successor status bit,
Zero the transmitter fault count located in the private area,
Load free FD and BD pool pointers from the private area to the TBC,
Return command confirmation, and
Enter the IDLE state.
The coding for this command is 'FO' and its format is shown below:
1
I
1
I
1
I
1
o
I
0
I
0
3.2.5 RESET Command
This command is equivalent to a hardware reset and is used to reset the TBC. RESET may be
issued to the TBC with the semaphore register equal to 'FE' or 'FF'. It:
Sets the semaphore register to 'FE' hex,
Returns all modes to their default values of zero except for HLEN which defaults to one (see
3.3.3 SET MODE 3 Command),
MOTOROLA
MC68824 USER'S MANUAL
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