PDSP1601/PDSP1601A
PDSP1601/PDSP1601A
ALU and Barrel Shifter
DS3705
ISSUE 3.0
November 1998
The PDSP1601 is a high performance 16-bit arithmetic
logic unit with an independent on-chip 16-bit barrel shifter.
The PDSP1601A has two operating modes giving 20MHz or
10MHz register-to-register transfer rates.
The PDSP1601 supports Multicycle multiprecision
operation. This allows a single device to operate at 20MHz for
16-bit fields, 10MHz for 32-bit fields and 5MHz for 64-bit fields.
The PDSP1601 can also be cascaded to produce wider words
at the 20MHz rate using the Carry Out and Carry In pins. The
Barrel Shifter is also capable of extension, for example the
PDSP1601 can used to select a 16-bit field from a 32-bit input
in 100ns.
PIN 1A INDEX MARK
ON TOP SURFACE
A
B
C
D
E
F
G
H
J
K
L
11 10 9
8 7
6
5 4
3
2
1
AC84
FEATURES
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16-bit, 32 instruction 20MHz ALU
16-bit, 20MHz Logical, Arithmetic or Barrel Shifter
Independent ALU and Shifter Operation
4 x 16-bit On Chip Scratchpad Registers
Multiprecision Operation; e.g. 200ns 64-bit
Accumulate
Three Port Structure with Three Internal Feedback
Paths Eliminates I/O Bottlenecks
Block Floating Point Support
300mW Maximum Power Dissipation
84-pin Pin Grid Array or 84 Contact LCC Packages
or 100 pin Ceramic Quad Flat Pack
GC100
Fig.1 Pin connections - bottom view
APPLICATIONS
ORDERING INFORMATION
PDSP1601 MC GGCR
PDSP1601A BO AC
N.B
10MHz MIL883 Screened -
QFP package
20MHz Industrial - PGA
package
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Digital Signal Processing
Array Processing
Graphics
Database Addressing
High Speed Arithmetic Processors
ASSOCIATED PRODUCTS
PDSP16112
PDSP16116
PDSP16318
PDSP16330
Complex Multiplier
16 x 16 Complex Multiplier
Complex Accumulator
Pythagoras Processor
Further details of the Military grade part are
available in a separate datasheet (DS3763)
1
PDSP1601/PDSP1601A
PIN DESCRIPTION
AC pin Function AC pin Function AC pin Function AC pin Function
C6
A6
A5
B5
C5
A4
B4
A3
A2
B3
A1
B2
C2
B1
C1
D2
D1
E3
E2
E1
F1
IA4
MSB
MSS
B15
B14
B13
B12
B11
B10
B9
B8
B7
B6
B5
B4
B3
B2
B1
B0
CEB
CLK
F3
G3
G1
G2
F1
H1
H2
J1
K1
J2
L1
K2
K3
L2
L3
K4
L4
J5
K5
L5
K6
GND
MSA0
MSA1
A15
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
CEA
MSC
J6
J7
L7
K7
L6
L8
K8
L9
L10
K9
L11
K10
J10
K11
J11
H10
H11
F10
G10
G11
G9
IS0
IS1
IS2
IS3
SV0
SV1
SV2
SV3
SVOE
RS0
RS1
VCC
RS2
C0
C1
C2
C3
C4
C5
C6
C7
F9
F11
E11
E10
E9
D11
D10
C11
B11
C10
A11
B10
B9
A10
A9
B8
A8
B6
B7
A7
C7
GND
C8
C9
C10
C11
C12
C13
C14
C15
OE
BFP
VCC
CO
RA0
RA1
RA2
CI
IA0
IA1
IA2
IA3
GC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
SIG
N/C
N/C
N/C
N/C
VCC
C0
RA0
RA1
RA2
CI
IA0
IA1
IA2
IA3
IA4
MSB
MSS
B15
B14
B13
B12
B11
B10
B9
B8
GC
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
SIG
N/C
N/C
N/C
N/C
B7
B6
B5
B4
B3
B2
B1
B0
CEB
CLK
GND
MSA0
MSA1
A15
A14
A13
A12
A11
A10
A9
A8
GC
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
SIG
N/C
N/C
N/C
N/C
A7
A6
A5
A4
A3
A2
A1
A0
CEA
MSC
IS0
IS1
IS2
IS3
SV0
SV1
SV2
SV3
SVOE
RS0
RS1
GC
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
SIG
N/C
N/C
N/C
N/C
VCC
RS2
C0
C1
C2
C3
C4
C5
C6
C7
GND
C8
C9
C10
C11
C12
C13
C14
C15
OE
BFP
N/C = not connected - leave open circuit
All GND and VDD pin must be used
2
PDSP1601/PDSP1601A
PIN DESCRIPTIONS
Symbol
MSB
MSS
B15 - B0
CEB
CLK
MSA0 - MSA1
A15 - A0
CEA
MSC
IS0 - IS3
SV0 - SV3
Description
ALU B-input multiplexer select control.
1
This input is latched internally on the rising edge
of CLK.
Shifter Input multiplexer select control.
1
This input is latched internally on the rising edge
of CLK.
B Port data input.
Data presented to this port is latched into the input register on the rising
edge of CLK. B15 is the MSB.
Clock enable, B Port input register.
When low the clock to this register is enabled.
Common clock to all internal registered elements.
change on the rising edge of CLK.
All registers are loaded, and outputs
ALU A-input multiplexer select control.
1
These inputs are latched internally on the rising
edge of CLK.
A Port data input.
Data presented to this port is latched into the input register on the rising
edge of CLK. A15 is the MSB.
Clock enable, A Port input register.
When low the clock to this register is enabled.
C-Port multiplexer select control.
1
This input is latched internally on the rising edge
of CLK.
Instruction inputs to Barrel Shifter, IS3 = MSB.
1
These inputs are latched internally on the
rising edge of CLK.
Shift Value I/O Port.
This port is used as an input when shift values are supplied from
external sources, and as an output when Normalise operations are invoked. The I/O functions
are determined by the IS0 - IS3 instruction inputs, and by the
SVOE
control.
The shift value is latched internally on the rising edge of CLK.
SV Output enable.
When high the SV port can only operate as an input. When low the SV
port can act as an input or as an output, according to the IS0 - IS3 instruction. This pin should
be tied hihg or low, depending upon the application.
Instruction inputs to Barrel Shifter registers.
1
These inputs are latched internally on the
rising edge of CLK.
C Port data output.
Data output on this port is selected by the C output multiplexer.
C15 is the MSB.
Output enable.
The C Port outputs are in high impedance condition when this control is high.
Block Floating Point Flag
from ALU, active high.
Carry out
from MSB of ALU.
Instruction inputs to ALU registers.
1
These inputs are latched internally on the rising
edge of CLK.
Carry in
to LSB of ALU.
Instruction inputs to ALU.
1
IA4 = MSB. These inputs are latched internally on the rising
edge of CLK.
+5V supply:
Both Vcc pins must be connected.
0V supply:
Both GND pins must be connected.
SVOE
RS0, RS1
RS2
C0 - C15
OE
BFP
CO
RA0 - RA2
CI
IA0 - IA3
IA4
Vcc
GND
NOTES
1.
All instructions are executed in the cycle commencing with the rising edge of the CLK which latches the inputs.
3
PDSP1601/PDSP1601A
A INPUT
16
A REG
CEA
B INPUT
16
B REG
CEB
A MUX
MSA0-1
2
B MUX
MSB
S MUX
MSS
BFP
CO
A
ALU
B
IA0-4
CI
5
BARREL SHIFTER
SHIFT
CONTROL
IS0-3
SV0-3
SVOE
RAD-2
3
3
ALU REG FILE
LEFT REG.
RIGHT REG.
RS0-2
SHIFTER REG FILE
LEFT REG.
RIGHT REG.
C MUX
MSC
OE
16
COUT
Fig.2 PDSP1601 block diagram
FUNCTIONAL DESCRIPTION
The PDSP1601 contains four main blocks: the ALU, the
Barrel Shifter and the two Register Files.
The ALU
The ALU supports 32 instructions as detailed in Table 1.
The inputs to the ALU are selected by the A and B MUXs.
Data will fall through from the selected register through the A
or B input MUXs and the ALU to the ALU output register file in
50ns for the PDSP1601A (100ns for the PDSP1601).
The ALU instructions are latched, such that the instruction
will not start executing until the rising edge of CLK latches the
instruction into the device.
The ALU accepts a carry in from the CI input and supplies
a carry out to the CO output. Additionally, at the end of each
cycle, the carry out from the ALU is loaded into an internal 1
bit register, so that it is available as an input to the ALU on the
next cycle. In the manner, multicycle, multiprecision
operations are supported. (See MULTICYCLE CASCADE
OPERATIONS).
BFP Flag
The ALU has a user programmable BFP flag. This flag
may be programmed to become active at any one of four
conditions. Two of these conditions are intended to support
Block Floating Point operations, in that they provide flags
indicating that the ALU result is within a factor of two or four of
overflowing the 16 bit number range. For multiprecision
operations the flag is only valid whilst the most significant 16
bit byte is being processed. In this manner the BFP flag may
be used over any extended word width.
The remaining two conditions detect either an overflow
condition or a zero result. For the overflow condition to be
active the ALU result must have overflowed into the 16th (sign)
bit, (this flag is only valid whilst the most significant 16 bit byte
is being processed). The zero condition is active if the result
from the ALU is equal to zero. For multiprecision operations
the zero flag must be active for all of the 16 bit bytes of an
extended word.
The BFP flag is programmed by executing on of the four
SBFXX instructions (see Table 1). During the execution of any
of these four instructions, the output of the ALU is forced to
zero.
Multicycle/Cascade Operation
The ALU arithmetic instructions contain two or three
options for each arithemtic operation.
The ALU is designed to operate with two's complement
arithmetic, requiring a one to be added to the LSB for all
subtract operations. The instructions set includes instructions
that will force a one into the LSB, e.g. MIAX1, AMBX1, BMAX1
(see Table 1).
These instructions are used for the least significant 16 bit
byte of any subtract operation.
The user has an option of cascading multiple devices, or
multicycling a single device to extend the arithmetic precision.
Should the user cascade multiple devices, then the cascade
arithmetic instructions using the external CI input should be
employed for all but the least significant 16 bit byte, e.g. MIACI,
APBCI, BMACI (see Table 1).
Should the user multicycle a single device, then the
Multicycle Arithmetic instructions, using the internally
registered CO bit should be employed for all but the least
significant 16 bit byte, e.g. MIACO, APBCO, AMBCO,
BMACO (see Table 1).
4
PDSP1601/PDSP1601A
Table 1 ALU instructions
1a. ARITHMETIC INSTRUCTIONS
Inst
00
01
02
03
04
05
06
07
08
09
0A
0B
0C
0D
0E
0F
IA4-AI0 Mnemonic
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
CLRXX
MIAX1
MIACI
MIACO
A2SGN
A2RAL
A2RAR
A2RSX
APBCI
APBCO
AMBX1
AMBCI
AMBCO
BMAX1
BMACI
BMACO
Operation
RESET
MINUS A
MINUS A
MINUS A
A/2
A/2
A/2
A/2
A PLUS B
A PLUS B
A MINUS B
A MINUS B
A MINUS B
B MINUS A
B MINUS A
B MINUS A
Function
CLEAR ALL REGISTERS
NA Plus 1
NA Plus CI
NA Plus CO
A/2 Sign Extend
A/2 with RAL LSB
A/2 with RAR LSB
A/2 with RSX LSB
A Plus B Plus CI
A Plus B Plus CO
A Plus NB Plus 1
A Plus NB Plus CI
A Plus NB Plus CO
NA Plus B Plus 1
NA Plus B Plus CI
NA Plus B Plus CO
Mode
---------
LSBYTE
CASCADE
MULTICYCLE
MSBYTE
MULTICYCLE
MULTICYCLE
MULTICYCLE
CASCADE
MULTICYCLE
LSBYTE
CASCADE
MULTICYCLE
LSBYTE
CASCADE
MULTICYCLE
1b. LOGICAL INSTRUCTIONS
Inst
10
11
12
13
14
15
16
17
IA4-AI0 Mnemonic
10000
10001
10010
10011
10100
10101
10110
10111
ANXAB
ANANB
ANNAB
ORXAB
ORNAB
XORAB
PASXA
PASNA
Operation
A AND B
A AND NB
NA AND B
A OR B
NA OR B
A XOR B
PASS A
INVERT A
Function
A. B
A. NB
NA. B
A+B
NA + B
A XOR B
A
NA
1c. CONTROL INSTRUCTIONS
Inst
18
19
1A
1B
1C
1D
1E
1F
IA4-AI0 Mnemonic
11000
11001
11010
11011
11100
11101
11110
11111
SBFOV
SBFU1
SBFU2
SBFZE
OPONE
OPBYT
OPNIB
OPALT
Operation
Set BFP Flag to OVR, Force ALU output to zero
Set BFP Flag to UND 1 Force ALU output to zero
Set BFP Flag to UND 2 Force ALU output to zero
Set BFP Flag to ZERO Force ALU output to zero
Output 0001 Hex
Output 00FF Hex
Output 000F Hex
Output 5555 Hex
KEY
A
B
CI
CO
RAL
RAR
RSX
MNEMONICS
= A input to ALU
= B input to ALU
= External Carry in to ALU
= Internally Registered Carry out from ALU
= ALU Register (Left)
= ALU Register (Right)
= Shifter Register (Left or Right)
CLRXX
MIAXX
A2XXX
APBXX
AMBXX
BMAXX
ANX-Y
ORX-Y
XORXY
PASXX
SBFXX
OPXXX
Clear All Registers to zero
Minus A,
XX = Carry in to LSB
A Divided by 2, XXX = Source of MSB
A Plus B,
XX = Carry in to LSB
A Minus B,
XX = Carry in to LSB
B Minus A,
XX = Carry in to LSB
AND
X
= Operand 1, Y = Operand 2
OR
X
= Operand 1, Y = Operand 2
Exclusive OR
X
= Operand 1, Y = Operand 2
Pass
XX = Operand
Set BFP Flag
XX = Function
Output Constant XXX
5
51mcu
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