P I N A S S I G N M E N T S 1. /MEMRQ ( I0 ) 20. VCC 2. /IORQ ( I1 ) 19. OUT ( B9 ) 3. /RDSTB ( I2 ) 18. INP ( B8 ) 4. NULLBUS ( I3 ) 17. INTA ( B7 ) 5. /REFRESH ( I4 ) 16. /WO ( B6 ) 6. /M1 ( I5 ) 15. /BEGIN ( B5 ) 7. 02 ( I6 ) 14. INST ( B4 ) 8. S0 ( I7 ) 13. MEMR ( B3 ) 9. S1 ( BI0 ) 12. ENINT ( B2 ) 10. GND 11. /WM1 ( B1 ) E Q U A T I O N S SMEMR = / /MEMRQ * / /RDSTB * / NULLBUS INST = / /MEMRQ * / /M1 * / NULLBUS BEGIN = / /MEMRQ * / /RDSTB ( MEMORY READ ) + / /MEMRQ * /RDSTB * /REFRESH ( MEMORY WRITE ) + / /IORQ * / 02 ( I/O CYCLE ) + / /MEMRQ * /REFRESH ( MEMORY CYCLE ) /WO = / /MEMRQ * /REFRESH * /RDSTB * / NULLBUS + / /IORQ * /RDSTB * /M1 * / NULLBUS INTA = / /M1 * / /IORQ * / NULLBUS + INTA * / INST * ENINT * / NULLBUS ENINT = /MEMRQ + / /RDSTB + / 02 INP = / /IORQ * / /RDSTB * / NULLBUS OUT = / /IORQ * /RDSTB * / INST * / NULLBUS /WM1 = / /M1 * / /MEMRQ ( WAIT ON M1 ) / /M1 * / /IORQ ( WAIT ON INTA ) / /MEMRQ * /REFRESH * / S0 ( WAIT ON MEMORY ) / /IORQ * / S1 ( WAIT ON I/O ) NOTES ON CURRENT ARTWORK REGARDING 82S153 ADDITION: 1. LIFT PIN 11 OF CHIP TO DISCONNECT ARTWORK TRACE BETWEEN 11 AND 12 (PIN 12 IS NOW USED AS AN INTERNAL FEEDBACK ONLY) 2. JUMPER /WM1 (TERM B1, PIN 11) OUTPUT TO /M1 INPUT OF 74LS175 ON BOARD FOR WAIT STATES INSTEAD OF CURRENT SETUP. 3. REMOVE THE 74S10 USED TO INVERT BEGIN OUT OF 82S153 AND JUST USE THE INVERTED BEGIN INSTEAD. 4. PROVIDE FOR JUMPERS TO PINS 8 AND 9 OF 82S153 TO GROND THEM FOR THE OPTIONAL WAIT ON MEMORY AND I/O CYCLES. THESE PINS SHOULD BE TIED HIGH THROUGH 4.7k PULLUPS.