IBM System/7 Functional Characteristics - All about the IBM 1130 ...

Read and Convert ADC0 5 8 11 16 20 26 31Op code R Fun Zeros Mod DA MA0 0 0 0 1 X XX 0 1 0 0 0 0 0 0 0 0 1 0 1 0 0 1 0 0 XXXXXXI 1 I 1 II 1 1 1 I 1 1 III 1 1 1 1 1 1 1 1 1 1•■■■••■■•■••• ••••••••■■• •–■••••,-■-•0 8-F 4 0 2 9 0-3 XThis command is used for repetitive operations on a single analog input point. Theread-and-convert-ADC command stores the binary output value from the ADC into the indexregister (R), or the accumulator if R=000, and starts another conversion cycle.Data transferred to the register can have either of two formats, depending upon whetherthe last convert command requested automatic gain or selected a particular amplifier gain.If automatic gain was selected, the 16 bits of data have the format:01 13 15S Data RRRTwelve bits of binary data plus sign (S bit) are returned. The RRR field indicates whichamplifier gain Was automatically selected by the amplifier. (Refer to the table in the"Convert Analog Input" command description.) If RRR=000, an overload conditionoccurred with the automatic gain selection.If a particular amplifier gain was selected by the last convert command, the 16 bitsof data have the format:0 1 15S Data OLFourteen bits of binary data plus sign (S bit) are returned. The single-bit OL field isset on if an overload condition occurred with the program selected amplifier gain.The convert portion of the read-and-convert-ADC command converts the analog inputpoint specified by the last convert command, utilizing the same amplifier gain. Thus, ifautomatic gain was specified by the last convert command, then automatic gain is also usedby each subsequent execution of the read-and-convert-ADC command.Since this command performs repetitive operations on a single analog input point, thesolid-state multiplexer is monopolized during this time. To terminate this repetitive readsequence and free the multiplexer, a read-ADC command must be issued if the result of thelast conversion cycle is needed by the program. However, any command other than theread-and-convert-ADC command may be issued to terminate the repetitive read sequence.The conversion cycle started by a read-and-convert-ADC command does not depend on anexternal synchronization pulse, nor can it be started by an external synchronization pulse.