Kawasaki 80C152, KS152JB, 80C51 Sending Abort Character, Line Idle, Acknowledgement

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KS152JB Universal Communications Controller Technical Specifications

required for implementing bit stuffing and striping are incorporated into the GSC hardware. This makes the operation transparent to the user. About the only time this operation becomes apparent to the user, is if the actual data on the transmission medium is being monitored by a device that is not aware of the automatic insertion of 0s. The bit stuffing/stripping guarantees that there will be at least one transition every 6 bit times while the line is active.

3.3.5 SENDING ABORT CHARACTER

An abort character is one of the exceptions to the rule that disallows more than 5 consecutive 1s. The abort character consists of any occurrence of seven or more consecutive ones. The simplest way for the C152 to send an abort character is to clear the TEN bit. This causes the output to be disabled which, in turn, forces it to a constant high state. The delay necessary to insure that the link is high for seven bit times is a task that needs to be handled by user software. Other methods of sending an abort character are using the IFS register or using the Raw Transmit mode. Using IFS still entails clearing the TEN bit, but TEN can be immediately re-enabled. The next message will not begin until the IFS expires. The IFS begins timing out as soon as DEN goes high which identifies the end of transmission. This also requires that IFS contain a value equal to or greater than 8. This method may have the undesirable effect that DEN goes high and disables the external drivers. The other alternative is to switch to Raw Transmit mode. Then, writing OFFH to TFIFO would generate a high output for 8 bit times. This method would leave DEN active during the transmission of the abort character.1

When the receiver detects seven or more consecutive 1s and data has been loaded into the receive FIFO, the RCABT flag is set in RSTAT and the frame is ignored. If no data has been loaded into the receive FIFO, there are no abort flags set and that frame is just ignored. A retransmitted frame may immediately follow an abort character, provided the proper flags are used.

3.3.6 LINE IDLE

If 15 or more consecutive 1s are detected by the receiver the Line Idle (LNI) in TSTAT is set. The seven 1s from the abort character may be included when sensing for a line idle condition. The same methods used for sending the Abort character can be used for creating the Idle condition. However, the values would need to be changed to reflect 15 bit times, instead of seven bit times.

3.3.7 ACKNOWLEDGEMENT

Acknowledgment in SDLC is an implied acknowledge and is contained in the control field. Part of the control frame is the sequence number of the next expected frame. This sequence number of is called the Receive Count. In transmitting the Receive Count, the receiver is in fact acknowledg- ing all the previous frames prior to the count that was transmitted. This allows for the transmis- sion of up to seven frames before an acknowledge is required back to the transmitter. The limitation of seven frames is necessary because the Receive Count in the control field is limited to three binary digits. This means that if an eighth transmission occurred this would cause the next Receive Count to repeat the first count that still is waiting for an acknowledge. This would defeat the purpose of the acknowledgment. The processing and general maintenance of the sequence

Kawasaki LSI USA, Inc.

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Ver. 0.9 KS152JB2

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Contents Introduction Technical Specifications Pin Description PIN DescriptionName Description Port Pin Name Alternate FunctionXTAL2 XTAL1RST ALE PsenEben EpsenSpecial function Registers SFR map for the cpuReset Timing Reset Values of the SFRs Configurations SconSbuf Indeterminate Tmod PconPort 0 I/O Pad Port 2 I/O Pad Port bit I/O PadsPorts 4,5 Program Psen EpsenComments Fetch viaTIMER/COUNTERS Tmod Timer/Counter Mode Control RegisterTcon Timer/Counter Control Register ModeTimer/Counter in Mode IE Interrupt Enable Register Timer/Counter 0 in ModeInterrupts Priority Level Structure Egste EDMA1 Egstv EDMA0 Egsre Egsrv Pgste PDMA1 Pgstv PDMA0 Pgsre PgsrvPX0 EX0Pgsrv Egsrv 2BHPDMA1 EDMA1PT1 ET1 1BHKawasaki LSI USA, Inc Ver .9 KS152JB2 Status of the External Pins during Idle and Power Down Power Down and IdleALE Psen Pcon Power Control Register Smod IDLLocal Serial Channel Local Serial Port Mode ControllerSerial Port Mode Mode Load Sbuf Baud Rates Smod Timer 1 generated commonly used Baud ratesMHZ JNB SINGLE-STEP OperationReti Kawasaki LSI USA Inc Global Serial Channel Introduction11/IDLE CRC None DC JAM CRCCsma Sdlc 11/IDLEExternal clock Internal clock Control cpu Control dma Raw Receive Raw Transmit CSMA/CD Frame Format CSMA/CD OverviewPreamble BOF Address Info CRC EOF Kawasaki LSI USA, Inc Ver .9 KS152JB2 23 24 Interframe Space CSMA/CD Data Encoding Manchester Encoding BIT TimeCollision Detection Jitter ToleranceMissing 0-to-1 Transition Narrow PulsesUnexpected 1-to-0 Transition Resolution of Collisions GSC InactiveResponse to a Detected Collision What the GSC was doing TfifoDCR BackoffAlgorithm Prbs Tcdcnt Load Bkoff Slot Clock Myslot Random BackoffBKOFF= Myslot Deterministic Backoff Hardware Based Acknowledge Kawasaki LSI USA, Inc Ver .9 KS152JB2 Sdlc Frame Format BOF Address Control Info CRC EOFKawasaki LSI USA, Inc Ver .9 KS152JB2 Nrzi BIT Time Data EncodingBIT STUFFING/STRIPPING Line Idle Sending Abort CharacterAcknowledgement PRIMARY/SECONDARY Stations Point-to-point NetworkMulti-Drop Network Ring NetworkUsing a Preamble in Sdlc HDLC/SDLC ComparisonSdlc Hdlc User Defined ProtocolsLine Discipline Planning for Network Changes and ExpansionsDMA Servicing of GSC Channels Kawasaki LSI USA, Inc Ver .9 KS152JB2 Baud Rate Initialization Test Modes External Driver InterfaceJitter Receive Local Value Manchester Encoding BIT Time Receive Sampling Rate ReceivedBIT Time Received Transmit WaveformsReceiver Clock Recovery CSMA/CD Clock RecoveryDetermining Receiver Errors External ClockingRcbat Crce AddressingDetermining Line Discipline 2 CPU/DMA Control of the GSCCollisions and Backoff What the GSC was doing Response GSC Register Descriptions Successful Ending of Transmissions and ReceptionsGMOD84H Xtclk PL1 PL0 PL1 PL0 Length BitsKawasaki LSI USA, Inc Ver .9 KS152JB2 DCJ DCR SA5 SA4 SA3 SA2 SA1 SA0 ARB REQ Garen Xrclk Gfien IDLRcabt Crce RDN Rfne Gren Haben Kawasaki LSI USA, Inc Ver .9 KS152JB2 LNI Noack Tcdt TDN Tfnf TEN DMA Kawasaki LSI USA, Inc Ver .9 KS152JB2 DMA Operation DMA with the 80C152DMA Registers Alternate Cycle Mode Burst ModeDAS IDA SAS ISASerial Port Demand Mode External Demand ModeTiming Diagrams 12 OSC.PERIODS ALE Psen P1 Inst FloatPCH P2 SFR DMA Cycle Resume Program Execution DMA Transfer from Internal Memory to Internal MemoryDMA Cycle 12 OSC. Periods Resume Program Execution ALE Psen 12 OSC. Periods ALE Psen Inst DMA Data OUT PCL Inst PCHDMA Cycle Resume Program Execution Arbiter Mode Request ModeHold/Hold Acknowledge Using the HOLD/HLDA Acknowledge ARB REQInternal Logic of the Arbiter ALE ARB If Hlda = ALE AEQ ALE REQDmxrq Internal Logic of the Requester DMA Arbitration Kawasaki LSI USA, Inc.oup, Inc Ver .9 KS152JB2 Kawasaki LSI USA, Inc Ver .9 KS152JB2 Kawasaki LSI USA, Inc Ver .9 KS152JB2 DMA Arbitration with Hold/Hold Ack Summary of DMA Control Bits DAS IDA SAS ISA DoneInterrupt Structure IE0 TI+RI ET1 EX1 ET0 EX0PT1 PX1 PT0 PX0 IPN1GSC Transmitter Error Conditions Transmit Error Flags Logic for Clearing TEN, Setting TDNGSC Receiver Error Conditions Glossary Kawasaki LSI USA, Inc Ver .9 KS152JB2 DCON0/1 092H,093H Xtclk PL1 PL0 Kawasaki LSI USA, Inc 102 Ver .9 KS152JB2 Kawasaki LSI USA, Inc 103 Ver .9 KS152JB2 PT1 PX1 PT0 EX0 Myslot 0F5H DCJ DCR SA5 SA4 SA3 SA2 SA1 SA0 Smod ARB REQ Garen Xrclk Gfien IDL OVR Rcabt Crce RDN Rfne Gren Haben Kawasaki LSI USA, Inc 108 Ver .9 KS152JB2 SM0 SM1 SM2 REN TB8 RB8 TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0Gate Kawasaki LSI USA, Inc 111 Ver .9 KS152JB2 Port Stack PointerData Pointer LOW DPL.7 DPL.6 DPL5 DPL.4 DPL.3 DPL.2 DPL.1 DPL.0Timer Control Data Pointer HighDPH.7 DPH.6 DPH.5 DPH.4 DPH.3 DPH.2 DPH.1 DPH.0 DPHTimer Mode Control Gate TimerTimer 0 LSB Timer 1 LSBTimer 0 MSB Timer 1 MSBSerial Port Control SM0Serial Data Buffer SBUF.7Program Status Word RS1 RS0Accumulator ACC.7 ACC.6 ACC.5 ACC.4 ACC.3 ACC.2 ACC.1 ACC.0Kawasaki LSI USA, Inc 119 Ver .9 KS152JB2 Kawasaki LSI USA, Inc 120 Ver .9 KS152JB2
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