User manual

Register Descriptions
A-5 Register Summary
Status Register ST0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
X X X 0 X 1
†
1 X X X X X X X X X
ARP OV OVM INTM DP
All unmasked interrupts enabled
All unmasked interrupts disabled
0
1
Auxiliary register pointer
Selects the current page
(0, 1, 2, ..., 511) in
data memory
Data page pointer
R/W R/W R/W
Selects the current auxiliary register
(0, 1, 2, 3, 4, 5, 6, or 7)
R/W
Accumulator results overflow normally.
Overflow mode selected
0
1
Flag is reset
Overflow detected in accumulator
0
1
R/W
Interrupt mode
Overflow mode
Overflow flag
†
This reserved bit is always read as 1. Writes have no effect.
Status Register ST1
151413 12 11 10 9 8765 4 32 1 0
XXX 0 X 1 11
†
1
†
1
†
1
†
11
†
1
†
00
ARB CNF TC SXM C XF PM
Auxiliary register pointer buffer
Product shift mode
R/W R/W R/W
Holds previous ARP value
R/W
Holds results of various software tests
DARAM B0 mapped to data memory
DARAM B0 mapped to program memory
0
1
R/WR/W
Test/control flag
Sign extension suppressed
Sign extension mode selected
0
1
R/W
Carry not generated/borrow generated
Carry generated/borrow not generated
0
1
XF pin low
XF pin high
0
1
No shift
Left shift of 1
Left shift of 4
Right shift of 6, sign extended
0
1
0
1
0
0
1
1
Carry bit
XF pin status
Sign-extension mode
DARAM B0 configuration
†
These reserved bits are always read as 1s. Writes have no effect.