Microchip Technology MA330020 Data Sheet

Page of 398
dsPIC33FJ06GS101/X02 and dsPIC33FJ16GSX02/X04
DS70000318G-page 34
 2008-2014 Microchip Technology Inc.
3.4
CPU Control Registers
      
REGISTER 3-1:
SR: CPU STATUS REGISTER
R-0
R-0
R/C-0
R/C-0
R-0
R/C-0
R-0
R/W-0
OA
OB
SA
(
SB
(
)
OAB
SAB
(
,
)
DA
DC
bit 15
bit 8
R/W-0
R/W-0
(
R/W-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
IPL2
(
IPL1
)
IPL0
(
)
RA
N
OV
Z
C
bit 7
bit 0
Legend:
C = Clearable bit
R = Readable bit
W = Writable bit
-n = Value at POR
‘1’ = Bit is set
0’ = Bit is cleared
‘x = Bit is unknown
U = Unimplemented bit, read as ‘0’
bit 15
OA: Accumulator A Overflow Status bit
1
 = Accumulator A has overflowed
0
 = Accumulator A has not overflowed
bit 14
OB: Accumulator B Overflow Status bit
1
 = Accumulator B has overflowed
0
 = Accumulator B has not overflowed
bit 13
SA: Accumulator A Saturation ‘Sticky’ Status bit
(
)
1
 = Accumulator A is saturated or has been saturated at some time
0
 = Accumulator A is not saturated
bit 12
SB: Accumulator B Saturation ‘Sticky’ Status bit
(
)
1
 = Accumulator B is saturated or has been saturated at some time
0
 = Accumulator B is not saturated
bit 11
OAB: OA || OB Combined Accumulator Overflow Status bit
1
 = Accumulator A or B has overflowed
0
 = Neither Accumulator A or B has overflowed
bit 10
SAB: SA || SB Combined Accumulator ‘Sticky’ Status bit
(
,
1
 = Accumulator A or B is saturated or has been saturated at some time in the past
0
 = Neither Accumulator A or B is saturated
bit 9
DA: DO Loop Active bit
1
 = DO loop in progress
0
 = DO loop not in progress
bit 8
DC: MCU ALU Half Carry/Borrow bit
1
 = A carry-out from the 4th low-order bit (for byte-sized data) or 8th low-order bit (for word-sized data)
of the result occurred
0
 = No carry-out from the 4th low-order bit (for byte-sized data) or 8th low-order bit (for word-sized
data) of the result occurred
Note 1:
This bit can be read or cleared (not set).
2:
The IPL<2:0> bits are concatenated with the IPL<3> bit (CORCON<3>) to form the CPU Interrupt Priority 
Level (IPL). The value in parentheses indicates the IPL if IPL<3> = 1. User interrupts are disabled when 
IPL<3> = 1.
3:
The IPL<2:0> Status bits are read-only when NSTDIS = 1 (INTCON1<15>).
4:
Clearing this bit will clear SA and SB.