ocr: THE Z-80 MICROPROCESSOR (Continued) 906150 Z-80 MICROPROCESSOR A11- 1 40 FA10 18 HALT Halt State. Active low output indicating that A12- 2 39 FA9 the andi is Z-80 awaiting has executed some a kind of HALT interrupt instruction before A13- 3 38 FA8 execution the can CPU continue. continuously While in executes tha HALT NOPS state, A14- 4 37 FA7 to continue refresh activity, A15- 5 36 FA6 19 MEMREQ that Memory indicates Request. that the Active address low, bus tri-state holds output a PHI- 6 35 FA5 valid address for a memory read or write D4- 7 34-A4 20 tORG operation. Input/Output Heguest. Act ...
