Specifications

Contents
Prefetch Pointer (PFP) ........................................ 6-6
General Purpose Registers
..................................... 6-6
Pointers and Index Registers
................................... 6-7
Program Status Word (PSW) [FL]
.............................. 6-8
V20 ARCHITECTURAL ENHANCEMENTS
....................... 6-9
Dual Data Bus
............................................... 6-9
Effective Address Generator
................................... 6-9
16/32-Bit Temporary Shift Registers (TA,TB)
.................. 6-10
Loop Counter (LC)
.......................................... 6-10
Program Counter (PC) and Prefetch Pointer (PFP)
.............. 6-10
Enhanced and Unique Instructions
............................. 6-11
MODE OPERATIONS - 8080 EMULATION MODE
............... 6-12
Break for Emulation (BRKEM)
............................... 6-14
Return From Emulation (RETEM)
............................ 6-14
Call Native Routine (CALLN)
................................ 6-15
Return from Interrupt (RETI)
................................. 6-15
Register Use in Emulation Mode
.............................. 6-16
DMA SUPPORT
................................................ 6-18
RESET STATE
................................................. 6-20
WAIT-STATE GENERATOR
..................................... 6-21
Chapter 7. NUMERIC DATA PROCESSOR (8087) 7-1
OVERVIEW
..................................................... 7-1
zSBC 337 PIGGYBACK PROCESSOR
............................ 7-3
INSTALLING THE zSBC 337
..................................... 7-4
COPROCESSOR INTERFACE
.................................... 7-7
MEMORY ADDRESSING
........................................ 7-8
INTERRUPT/NUMERIC ERRORS
................................ 7-9
REFERENCES
................................................. 7-13
Chapter 8. SERIAL COMMUNICATIONS (16C452) 8-1
OVERVIEW
..................................................... 8-2
SERIAL COMMUNICATIONS PROTOCOL
....................... 8-3
SERIAL INTERFACE (RS-232-C/422/485)
......................... 8-8
RS-232-C vs. RS-422/485
.................................... 8-10
Signal Definitions
........................................... 8-11
SERIAL REGISTERS
........................................... 8-16
Transmit and Receive Buffer Registers
........................ 8-20
Scratchpad Register
......................................... 8-20
Line Control Register
........................................ 8-21
Baud Rate Generator
......................................... 8-24