MK50H25DIP ST Microelectronics, Inc., MK50H25DIP Datasheet - Page 41

• Manufacturer Part Number: MK50H25DIP
• Description: High Speed Link Level Controller
• Manufacturer: ST Microelectronics, Inc.

4.4.2 Active Link Setup
The following procedure should be followed to actively establish a link.
1. Issue Connect Request primitive (UPRIM=6) through CSR1. The MK50H25 will attempt to establish a
2. Wait for a Connect Confirmation primitive (PPRIM=7) from the MK50H25 (indicating reception of UA
3. If a Connect Confirmation primitive is received, a link has been established.
4. If a Disconnect Indication primitive (PPRIM=14) is received, the MK5025 has been unable to establish
4.4.3 Passive Link Setup
The following procedure should be followed for passively establishing a link.
1. Issue a Disconnect Request primitive (UPRIM=14). If issued with UPARM=0, a DM/F=0 frame will be
2. Wait for a Connect Indication primitive (PPRIM=6) from the MK50H25.
3. If a Connect Indication primitive is received (indicating SABM frame has been received), issue a Con-
4. If no Connect Indication primitive is received, the remote station is not trying to establish a link.
4.4.4 Refusing Link Setup
The following procedure should be followed when refusing link establishment.
1. A Connect Indication primitive received indicates a request by the remote station to establish a link.
2. Issue a Disconnect Request primitive to refuse to establish the link (causes MK50H25 to respond with
4.4.5 Sending Data
Use the following procedure to send a frame:
1. Wait for the OWNA bit of the current transmit descriptor to be cleared, if it is not already.
2. Fill the buffer associated with the current transmit descriptor with the data to be sent, or set the de-
3. Repeat steps 1 & 2 for next buffer if chaining is necessary, setting SLF, ELF and MCNT appropriately.
4. Set the OWNA bit for each descriptor used.
5. Go on to next descriptor. The OWNA bits will be cleared when data has been sent successfully and
4.4.6 Receiving Data
The following procedure should be followed when receiving a frame:
1. Make sure the OWNA bit of the current receive descriptor is clear.
2. Read data out of the buffer associated with the current receive descriptor.
3. Set the OWNA bit of the current receive descriptor.
4. If the ELF bit of the current receive descriptor is clear, then go on to the next descriptor and repeat
4.4.7 Link Disconnect
The following procedure should be followed to disconnect an established link.
1. Issue the Disconnect Request primitive to the MK50H25.
2. A Disconnect Confirmation primitive (PPRIM=15) will be issued after successful disconnection, and the
logical link. It does this by sending a SABM/P=1 frame, and repeats sending it at T1 timer intervals un-
til a response is received or N2 have been sent (in which case it would issue PPRIM=14 with
PPARM=1).
frame in response to SABM sent).
a link. The reason will be in the PPARM field of CSR1.
sent; if issued with UPARM=1, a DISC/P=0 frame will be sent to the remote station requesting link
setup. This step is optional in many cases, but some networks require either a DM or DISC be sent to
initiate passive link setup.
nect Response primitive to indicate willingness to establish the link (causes MK50H25 to respond with
a UA frame). The link is now established.
a DM or DISC frame depending on value of UPARM).
scriptor buffer address to any already filled buffer.
acknowledged. In Transparent Mode, OWNA bits are cleared immediately after frame transmission.
the above steps appending data from each buffer until a descriptor with the ELF bit set is reached.
MK50H25 will go into Normal Disconnected state.
MK50H25
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