IS80C286-20 Intersil, IS80C286-20 Datasheet - Page 8

• Manufacturer Part Number: IS80C286-20
• Description: IC CPU 16BIT 5V 20MHZ 68-PLCC
• Manufacturer: Intersil

Specifications of IS80C286-20

• Processor Type: 80C286 16-Bit
• Speed: 20MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 68-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -

BIT POSITION
FLAGS:
MSW:
11
10
0
2
4
6
7
8
9
AUXILIARY CARRY
15
15
STATUS FLAGS:
OVERFLOW
RESERVED
NT
14
NAME
PARITY
OF
CARRY
CF
PF
AF
ZF
SF
TF
DF
IF
ZERO
SIGN
13
IOPL
FIGURE 2. STATUS AND CONTROL REGISTER BIT FUNCTIONS
Carry Flag - Set on high-order bit carry or borrow; cleared otherwise.
Parity Flag - Set if low-order 8 bits of result contain an even number of 1 bits; cleared otherwise.
Set on carry from or borrow to the low order four bits of AL; cleared otherwise.
Zero Flag - Set if result is zero; cleared otherwise.
Sign Flag - Set equal to high-order bit of result (0 if positive, 1 if negative).
Overflow Flag - Set if result is a too-large positive number or a too-small negative number (excluding
sign-bit) to fit in destination operand; cleared otherwise.
Single Step Flag - Once set, a single step interrupt occurs after the next instruction executes. TF is
cleared by the single step interrupt.
Interrupt-Enable Flag - When set, maskable interrupts will cause the CPU to transfer control to an inter-
rupt vector specified location.
Direction Flag - Causes string instructions to auto decrement the appropriate index registers when set.
Clearing DF causes auto increment.
12
OF
TABLE 1. FLAGS WORD BIT FUNCTIONS
11
10
DF
PROCESSOR EXTENSION EMULATED
MONITOR PROCESSOR EXTENSION
IF
9
80C286
TF
8
8
PROTECTION ENABLE
SF
7
TASK SWITCH
FUNCTION
ZF
6
5
CONTROL FLAGS:
TRAP FLAG
INTERRUPT ENABLE
DIRECTION FLAG
SPECIAL FIELDS:
I/O PRIVILEGE LEVEL
NESTED TASK FLAG
AF
4
TS
3
3
EM
PF
2
2
MP
1
1
CF
PE
0
0