dp8344b National Semiconductor Corporation, dp8344b Datasheet - Page 140

• Manufacturer Part Number: dp8344b
• Description: Biphase Communications Processor?bcp
• Manufacturer: National Semiconductor Corporation

Figure 6-1
6 0 Reference Section
CPL Complement
Syntax
CPL Rsd
Affected Flags
N Z
Description
Logically complements the contents of the register Rsd
placing the result back into that register
Example
Load the fill-bit count passed from the host into the Trans-
mitter’s Fill-Bit Register FBR
required one’s complement of the fill-bit count In this exam-
ple register 20 contains the fill-bit count
Instruction Format
T-states
2
Bus Timing
Operation
Rsd
1
15
EXX
MOVE
CPL
x
0
Rsd
1
0
1 1
R20 FBR
FBR
1
Opcode
register
1
1
select alternate banks
complement fill-bit count
load FBR
0
0
R3 and then perform the
0
(Continued)
0
4
Rsd
0
140
Figure 6-1
EXX Exchange Register Banks
Syntax
EXX ba bb
Affected Flags
None
Description
Selects which CPU register banks are active by exchanging
between the main and alternate register sets for each bank
Bank A controls R0 – R3 and Bank B controls R4 – R11 The
table below shows the four possible register bank configura-
tions Note that deactivated registers retain their current val-
ues The Global Interrupt Enable bit GIE can be set or
cleared if desired
Example
Activate the main register set of Bank A the alternate regis-
ter set of Bank B and leave the Global Interrupt Enable bit
Instruction Format
T-states
2
Bus Timing
Operation
Case ba of
End case
Case bb of
End case
Case g of
End case
GIE unchanged
1 0 1 0 1 1 1 0 1
15
EXX
0
1
0
1
0
1
2
3
activate main Bank A
activate alternate Bank A
activate main Bank B
activate alternate Bank B
leave GIE unaffected (default)
(reserved)
set GIE
clear GIE
ba
0
0
1
1
0 1
Opcode
Register Bank Configurations
g
bb
0
1
0
1
select main A alt B reg banks
Active Register Banks
Main A Main B
Main A Alternate B
Alternate A Main B
Alternate A Alternate B
6
00 GIE not affected
01 reserved
10 Set GIE
11 Clear GIE
v
g
ba bb
4
3
0 0 0
2
0