PIC17C752-25I/P View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC17C752-25I/P

High-Performance 8-Bit CMOS EPROM Microcontrollers

Microchip Technology 

PIC17C75X

FIGURE F-2: ALUSTA REGISTER (ADDRESS: 04h, UNBANKED)

R/W - 1 R/W - 1 R/W - 1 R/W - 1 R/W - x

FS3 FS2 FS1 FS0

OV

bit7

R/W - x

Z

bit 7-6:

FS3:FS2: FSR1 Mode Select bits

00 = Post auto-decrement FSR1 value

01 = Post auto-increment FSR1 value

1x = FSR1 value does not change

R/W - x R/W - x

DC

C

bit0

R = Readable bit

W = Writable bit

-n = Value at POR reset

(x = unknown)

bit 5-4:

FS1:FS0: FSR0 Mode Select bits

00 = Post auto-decrement FSR0 value

01 = Post auto-increment FSR0 value

1x = FSR0 value does not change

bit 3:

OV: Overflow bit

This bit is used for signed arithmetic (2’s complement). It indicates an overflow of the 7-bit magnitude,

which causes the sign bit (bit7) to change state.

1 = Overflow occurred for signed arithmetic, (in this arithmetic operation)

0 = No overflow occurred

bit 2:

Z: Zero bit

1 = The result of an arithmetic or logic operation is zero

0 = The results of an arithmetic or logic operation is not zero

bit 1:

DC: Digit carry/borrow bit

For ADDWF and ADDLW instructions.

1 = A carry-out from the 4th low order bit of the result occurred

0 = No carry-out from the 4th low order bit of the result

Note: For borrow the polarity is reversed.

bit 0:

C: carry/borrow bit

For ADDWF and ADDLW instructions.

1 = A carry-out from the most significant bit of the result occurred

Note that a subtraction is executed by adding the two’s complement of the second operand. For

rotate (RRCF, RLCF) instructions, this bit is loaded with either the high or low order bit of the source

register.

0 = No carry-out from the most significant bit of the result

Note: For borrow the polarity is reversed.

DS30264A-page 274

Preliminary

© 1997 Microchip Technology Inc.

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