MK50H27 datasheet(18/56 Pages) STMICROELECTRONICS

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to continuously transmit SIOS signal units.

Init: instructs the MK50H27 to read the initialization block from memory.

Valid only in the Power Off mode.

Trans: instructs the MK50H27 to enter the HDLC Transparent phase of

operation. Data frames are transmitted and received out of the de-

scriptor rings but no protocol processing is done. Address and

Control fields are not prepended to the frames, but CK processing

works normally. HDLC Transparent Mode may be exited only with a

Power Off primitive or by a bus RESET. Valid only in the Power Off

phase.

Status Request: instructs the MK50H27 to write the current link status

into the STATUS BUFFER.

Valid in

all

states,

but

only after

the Init primitive has been previously issued.

Self-Test Request: instructs the MK50H27 to perform the built in

internal self test. Valid only in the Power Off phase. See section 4.4.8

for the self test procedure.

Stop: forces all DMA activity to cease. Causes the MK50H27 to enter the

Out of Service phase and to continuously transmit SIOS signal units.

Valid in all phases except the Power Off and Out of Service phase.

Start: initial alignment begins and the descriptor rings are reset. Start

should only be issued when in the Out of Service phase, after the in-

itialization block has been read.

Local Processor Outage: issued to the MK50H27 to indicate that level

3 or higher levels cannot accept signalling messages. All subsequent

MSU’s are ignored by the MK50H27 & SIPO signal units are transmit-

ted.

Local Processor Recovered: indicates end of Local Processor Outage

condition. The MK50H27 may resume transmitting FISUs and MSUs.

Emergency: indicates that the emergency proving period is to be used

for initial alignment.

Emergency Ceases: Indicates that the normal proving period is to be

used for initial alignment (this is the default proving period).

Retrieve BSNT: causes the entire STATUS BUFFER to be updated

including the last transmitted Backward Sequence Number (BSNT).

When completed, PPRIM 18 will be issued.

Retrieval request and FSNC: indicates that the FSNC has been

written to the Status Buffer and requests the MK50H27 to update the

retransmission buffer. The MK50H27 should then place

the up-

dated retransmission index into the Status Buffer.

Congestion: causes the MK50H27 to enter a congestion state and send

SIB signal units at T5 timer interval. It is recommended that the DRX

bit in CSR0 also be set when issuing this primitive so that MSUs can-

not be received during congestion.

Clear Congestion: This primitive should be used only to clear the

Congestion state caused by UPRIM 14. If DRX is set, it should be

cleared just prior to issuing this primitive. If congestion state was en-

tered due to a MISSed signal unit then the congestion state should be

cleared by clearing MISS.

Start Sending SIOS: If JSS7E=1, this primitive can be used to resume

sending of SIOS signal units, stopped by issuance of UPRIM 17. Valid

only in Out Of Service phase when JSS7E=1 (CSR2).

Stop Sending SIOS: If JSS7E=1, this primitive can be used to stop the

transmission of SIOS signal units while the MK50H27 is in the Out of

Service phase.

TTC specification JT-Q703 requires that transmission

of SIOS stop some period of time after going Out Of Service; this primi-

tive provides the mechanism for meeting that requiremnt. Transmis-

MK50H27

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