NEC PD78078 用户手册

7

0

IE

PSW

Z

RBS1

AC

RBS0

0

ISP

CY

PC

15

0

PC15 PC14 PC13 PC12 PC11 PC10

PC9

PC8

PC7

PC6

PC5

PC4

PC3

PC2

PC1

PC0

The 

µ

PD78078 and 78078Y Subseries units incorporate the following processor registers.

The control registers control the program sequence, statuses, and stack memory.  The control registers consist

of a program counter (PC), a program status word (PSW), and a stack pointer (SP).

The program counter is a 16-bit register which holds the address information of the next program to be

executed.

In normal operation, the PC is automatically incremented according to the number of bytes of the instruction

to be fetched.  When a branch instruction is executed, immediate data and register contents are set.

RESET input sets the reset vector table values at addresses 0000H and 0001H to the program counter.

The program status word is an 8-bit register consisting of various flags to be set/reset by instruction

execution.

Program status word contents are automatically stacked upon interrupt request generation or PUSH PSW

instruction execution and are automatically reset upon execution of the RETB, RETI and POP PSW instructions.

RESET input sets the PSW to 02H.