Giant Meter wave Radio Telescope National Center for Radio Astrophysics Tata Institute of Fundamental Research NCRA·TTF'R Interface between a PC parallel port and GPIB devices Author: L. Pommier Project director: T.L.VeHkanmuBHUllmll Date: 06102104 Table of Contents 1.Introduction................................................................................................................................... 2­ 2.The GPm interface .......................................................................................................................§. 2.1.GPIB messages....................................................................................................................................................2 2.2.GPIB devices.......................................................................................................................................................2 2.3.6PIB Signals........................................................................................................................................................2 2.3.1.Data lines....................................................................................................................................................Z 2.3.2.Management lines......................................................................................................................................Z 2.3.3.Handshake lines.........................................................................................................................................Z 2.4.The handshaldng protocol. ..................................................................................................................................§. 3.The parallel port interface ............................................................................................................ ,2 3.1.The interface modes............................................................................................................................................ 2­ 3.2.The parallel port signals ......................................................................................................................................2 3.2.1.The Data Register.................................................................................................................................... 10 3.2.2. The Status Register.................................................................................................................................. 10 3.2.3.The Control Register................................................................................................................................ 11 3.3.Accessing the parallel port................................................................................................................................ 12 3.3. 1.Programming ways.................................. ................................................................................................12 3.3.2.Linux direct access and results...............................................................................................................12 4.The existing parallel port-to-GPm interlace .......... .. ........................................................ 13 4.1.The parallel port-to-GPIB driver...................... ...................................................... 13 4.2.Cable connection between the two' ................................................11 4.3.Electrical specifications................................ .. ................................................ 15 4.3. 1.Parallel port electrical ..................................................... 15 4.3.2. GPIB electrical specifications........... ........................................ 16 4.4.Electrical compatibility between the two ................................ 17 4.4. 1. Output types.............................................. .................................................. 17 4.4.1.1.Open-collector and open-drain.......... ~. ....................17 4.4.1.2.Totem-pole and push-pull............ ;.................................................................................................. 17 4.4.I.3.Tri-state............................................................................................................................................j! 4.4.1.4.Conc1usion.......................................................................................................................................ll 4.4.2.Conclusicn on electrical compatibility between the two inteifaces..................................................... 19 5.Further interlacing solution: the adapter box ............................................................................20 5.I.Introduction............................................................................................ ~ ...........................................................20 5.2.Adapter box Design........................................................................................................................................... 21 5.2.1.Adapter box without direction control................................................................................................... 21 5.2.1.1.Presentation......................................................................................................................................21 5.2.1.2.Resistances not compatible with GPIB currents ...........................................................................21 5.2.2.Adap(er box with a 3-state controL .......................................................................................................23 5.2.2.1.Presentation......................................................................................................................................23 5.2.2.2.Final adapter box design .................................................................................................................24 TIFR - NCRA - GMRT Technical Report Parallel port 1GPm interface 2/28 6.Multi-devices testing and further proceedings ..........................................................................25 6.1.Multi-devices testing .........................................................................................................................................25 6.2.Further proceedings ..........................................................................................................................................25 7 .Conclusion............................................................................ :.................... :................................ 26 8.References...................................................................................................................................27 9 .Appendix................................................................................................................ ~ ....................28 Illustration Index Illustration I : GPm devices...........................................................................................................................................6 Illustration 2 : GPm handshaking..................................................................................................................................8 Illustration 3 : Parallel port GPm hybrid cable and connectors ............................................................................. 13 Illustration 4: IEEE 488 bus current according to bus voltage ................................................................................. 16 Fig. 5 : open-collector output........................................................................................................................................ 17 Fig. 6 : bidirectional line with open-collector outputs................................................................................................ 17 Fig.7: Totem-pole output............................................................................................................................................ 17 Fig. 8 : Tri-state oUtpul ................................................................................................................................................. 18 Illustration 9 : Linear-chained configuration ...............................................................................................................20 TIlustration 10: Star-chained configuration................................................................................................................. 20 Illustration. 11 : Adapter box transceiver without direction control for bidirectionallines ....................................21 Illustration. 12: Adapter box transceiver with a 3-state control for bidirectionallines........................................... 23 Illustration 13: Adapter box design .............................................................................................................................24 Illustration 14 ; Test setting.......................................................................................................................................... 25 TIFR - NCRA - GMRT Technical Report Parallel port I GPIB interface 3128 Index of Tables Table I : Parallel port bits of the Data Register.......................................................................................................... 10 Table 2 : Parallel port bits of the Status Register.................................................................................................... ;... 10 Table 3: Parallel