Dynamic Shift Registers - Bitsavers - Trailing-Edge

ROM Code Convertersrn"owSK0003 sine/cosine look-up table kitgeneral descriptionThe SK0003 Sine/Cosine Look-Up Table Kit consistsoffour MaS ROMs: three MM4210/MM5210'sand one MM4220/MM5220-1024 bit static readonly memories. They are P-channel enhancementmode monolithic MaS integrated circuits utilizinga low threshold technology.THE SINE FUNCTIONThe SK0003 implements the equation sinO = sinM cos L + cos M sin L. Cos L was assumed to be1 in the equation. However, it is a variable between1 and 0.99998 and is a function of round off error.Worst case error is 1-5/8 bits in LSB at address1415 (62.25°). The error increases from zero to.002% every 8 bits, therefore, the MM4220/MM5220 provides the error correction factorcos(M - 2.81°)sin L in the equation sinO = sinM +cos(M - 2.81°)sin L. The circuitry to perform thisfunction is shown in Figure 1. Additional informationis available in MOS Brief 10.THE COSINE FUNCTIONTo generate the cosine function cosO = sin (0 -90°), the input must be complemented and alogical "1" added. Figure 2A is a logic diagramof the circuitry used to provide the cosine function,as well as providing both sine and cosinefunctions in the same system. 11-bit resolutionand 12-bit accuracy ±1-5/8-bits is achieved in thisconfiguration.A reduction in logic can be achieved as shown inFigure 2B if a loss in resolution of 1/2-bit in an11-bit input or 1/4-bit in a 10-bit input is acceptable.ELECTRICAL CHARACTERISTICSRefer to the appropriate data sheet for eachdevice shown in the figures. The devices noted are:MM4210/MM5210, MM4220/MM5220, DM5483/DM7483, DM7812/DM8812 and DM5486/DM7486.logic diagramGATES~)--.--{{A.I.A~ MM5210 8JMKOOII,B,I..·" B, "z'A, Z.. " ..• AI 0117413,I.'. , ,-,.," .. •11" I,CARRY INPUT.,.. CARRYOUTPUT,. .."i·'OM'''' '. ,.,IINARY"CARRY INPUTz·,v~{ .. B.{~A,MMS210B,MKOO9 ~A,B,CARRYOUTPUTD.fCl3CARRYI.PUT",.,"Z·11R~ (TO EACH OUTI'UT)-12VFIGURE 1. SK0003 Logic Diagram (Kit Includes ROMs Only). This Circuit Provides 11-Bit Resolution and 12-BitAccuracy in a 0 to Sin 0 Converter.179