Systems Reference Library - All about the IBM 1130 Computing ...

mode, operation of the line adapter is changed asfollows:1. In transmit mode, the send data line to thedata set is looped back to the input of theSERDES.2. All characters are read from or stored in bits8 through 15 of the data table words.3. After each character in transmit mode, andbefore each character in receive mode, thediagnostic device status word (DSW) is storedin the transmit and receive data tables,respectively. This storing is automaticallyaccomplished by means of data channel (cyclesteal) operations.Figure 98 illustrates the format of diagnostictransmit and receive data tables. Note that spacemust be reserved in the tables for the diagnosticDSW's. When constructing diagnostic data tables,consideration must be given to characters that maybe automatically inserted into the transmissionstream by the line adapter. With external clocking,for example, a synchronous idle sequence (SYN SYNor DLE SYN) is automatically inserted if a synchronousidle sequence is not detected in the data streamwithin 1 second intervals. The added synchronousidle sequence would add two additional diagnosticDSW's to both data tables. In transparent mode,this insertion can be avoided by using shorter datatables (approximately 50 characters in length). Innormal mode, SYN SYN sequences can be placed inthe transmit data table at intervals of less than1 second. Transparent mode transmission alsoleaves exposure to automatic insertion of a secondDLE following any DLE in the transmit data table.This DLE insertion would cause one additionaldiagnostic DSW in both data tables.The XIO sense device also provides a diagnosticfunction (program receive input) when a line adapteris in receive mode. Modifier bit 8 being di in theXIO sense device causes a space (0-bit) to enter theSERDES. A subsequent XIO sense device causes amark (1-bit) to enter the SERDES. Thus the input tothe SERDES can be program controlled with a seriesof XIO sense device appropriately timed.When using program receive input, the data setcable must be in test position to avoid interferencewith input data on the transmission line.CA PROGRAMMINGEach line adapter on a CA operates under data channelcontrol for data transfer. The two line adaptersReceive1000 I Byte Count2,d Di,gnostic DSW3rd Di agnostic DSW1st Character2nd Character3rd CharacterEnd Character Diagnostic DSWEnd Character1st BCC Diagnostic DSW2nd BCC Diagnostic DSWPad Diagnostic DSWPad Character* In Receive Diagnosticoperation, the 1st Diagnosticword is not stored.Only EBCDICFigure 98. CA Diagnostic Data TablesOwn AddressITransmit1010 I Byte Count1s t Dicdd tic DSW2nd DI,or,c6tic DSWByte CountN+1 CharacterN+1 Diagnostic DSW---,..--,.....--,---,...---..........End CharacterEnd Character Diagnostic DSW1st BCC Diagnostic DSW2nd BCC Diagnostic DSWPADPod D n i c tic DSW1st Character2nd Character3rd Character3rd Dicdn,tic DSWChain Word (if used)Nth CharacterAnythingChain Word (to Receive)111737Aof a CA may share a single data channel if concurrentoperation of both line adapters is not desired. However,if concurrent (overlap) operation, is desired,the line adapters must be assigned to separate datachannels.The line adapters are individually controlledthrough use of the execute I/O (XIO) instruction. Theinput/output control command (IOCC) referenced by anXIO must have an area code of 10101, 10110, 10111,or 10100 to address CA's 1, 2, 3, or 4, respectively.The following IOCC's are used for operation andcontrol of the line adapters.Communications Adapter 187