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

storage with one XIO initialize read to initiate theaction. The input/output control command (IOCC)address word contains the core storage address of adata table. The first word of the table contains thescan control bits and word count for the operation.The word count is 1 more than the number of inputgroups to be read. The scan control bits determinewhether an interrupt is given and whether chainingor termination of the operation occurs when the wordcount reaches O.The word following the word count and scan controlbits in the data table contains the initial inputgroup address for this data table. The data channel"writes" this address into digital input basic, whichthen initiates reading of the input group. After theinput group is read, the data is transferred by thedata channel to the next sequential core storage wordin the data table. Upon completion of each datatransfer, the word count is decreased by 1 and theinput group address is increased by 1. The new addresscauses the next sequential input group to beread.This operation continues until the word countreaches 0. At this time, the scan control bits aremonitored. If continuous scanning is indicated, thedata channel takes four cycles to initialize for thenext data table. The first cycle transfers the wordfollowing the first data table to the channel addressregister (CAR). This word contains the address ofthe next data table. The second cycle reads thefirst word of the next data table to the B-register.A CAR check is then made. The third cycle transfersthe word count and scan control bits to digitalinput basic. The fourth cycle transfers the initialinput group address for this data table to digital inputbasic. Data transfers then resume by means ofdata channel operations.Figure 46 shows two data tables which could beused for chained sequential operation. In this example,the IOCC initiating the operation is at locations3042 and'3043.Data channel sequential mode may be used withor without external sync.Data Channel Single AddressData channel single address mode of operation isidentical to data channel sequential mode of operationexcept that the initial input group address is notincreased after each data transfer. Therefore, thesame input group is read repeatedly. The data isplaced in sequential words of the data table until theword count reaches 0.Location(Decimal) 08 152999Scan Word Count = 1230003001•••3011301 2Location(Decimal)301530163017301 8•••3041304230430 8 15CAR Check Word = 3015Word Count = 25Input Group AddressData Word 12.11, • ... lllData Word 351.1111.11..1Starting Table Address = 2999DI-Initialize ReadInput Group AddressData Word 1 ......-- • -.• ._-11.,.1.0.,■•■■■■Data Word 11Next Table Address = 3015..,............•■•••••IOCC17223BFigure 46. Digital Input Data Tables, Chained Sequential ModeData channel single address mode may be usedwith or without external sync.Data Channel RandomUsing data channel random mode of operation, inputgroups can be read at random into core storage withone XIO initialize read to initiate the action. Theinput/output control command (IOCC) address wordcontains the core storage address of the data table.The first word of the table contains the scan controlbits and word count for the operation. The wordcount is twice the number of input groups to be read.The word following the word count and scancontrol bits in the data table is an input groupaddress. The data channel "writes" this addressinto digital input basic, which then initiatesreading of the input group. After the inputgroup is read, the data is transferred by the datachannel to the next sequential core storage wordin the data table. The data channel then "writes"Digital Input 119