PDSP1601_96 Datasheet, PDF (14/18 Pages) Mitel Networks Corporation – ALU and Barrel Shifter

PDSP1601/PDSP1601A
TYPICAL APPLICATION
Select a 16 bit field from each word in a block of 32 bit
words with a 10MHz throughput.
The 16 bit field indicated is to be selected from each 32 bit
word.
MS Byte
LS Byte
MS Bit
8
8
8
8
16 bits
nbits
The 32 bit words are fed into the B port of the PDSP1601
in two cycles, MS byte first.
The PDSP1601 shift control is initiated by programming
the R1 and R2 registers with n and 16-n respectively.
The shift operation is implemented in three steps:-
(1) The MS byte is logically left shifted (16-n) places, the
MSBs being discarded and the LSB spaces being filled with
zeros. This shifted data is loaded into the shifter register file
left register.
(2) The LS byte is logically right shifted, n-places, the
LSBs being discarded and the MSBs being filled with zeros.
This shifted data is loaded into the shifter register file left
register.
During this cycle the previous contents of this register are
passed through the ALU to the ALU register file left register.
(3) While the MS byte of the next 32 bit word is shifted in
the Barrel Shifter, the two previous results, resident within the
left registers of the ALU and Shifter Register files are 'ORed'
by the ALU, the result being the desired 16 bit field is loaded
into the ALU register file right register ready to be output on the
next cycle.
The instructions from initialisation are given in Table 6.
CLK CEB MSA MSB MSS MSC IA
IS
1/ 1 MARSX 1
0
0 CLRXX
X
2/ 1 MARSX 1
0
0 PASXA LR1SV
3/ 0 MARSX 1
0
0 PASXA LR2SV
4/ 0 MARSX 1
0
0 PASXA LSLR2
5/ 0 MARSX 1
0
0 PASXA LSRR1
6/ 0 MARAX 1
0
0 ORXAB LSLR2
7/ 0 MARSX 1
0
0 PASXA LSRR1
8/ 0 MARAX 1
0
0 ORXAB LSLR2
SV
RA
RS ^Comment
X
n
(16-n)
X
X
X
X
X
NOPLR
NOPLR
NOPLR
NOPLR
LLRRR
LRRLR
NOPLR
NOPLR
NOPLR
LLRLR
LLRLR
LLRLR
LLRRR _LLRLR
LRRLR _LLRLR
Clear
Load R1 with n
Load R2 with (16-n)
Shift 1st MS byte
Shift 1st LS byte
OR 1st bytes and
shift 2nd MS byte
Shift 2nd LS byte
and output first result
Shift 3rd LS byte
Repeat instruction pair 5/ and 6/ until all 16 bit fields have been selected.
Table 6
ABSOLUTE MAXIMUM RATINGS (Note 1)
Supply voltage Vcc
-0.5V to 7.0V
Input voltage V_IN
-0.9 to Vcc + 0.9V
Output voltage V_OUT
-0.9 to Vcc + 0.9V
Clamp diode current per pin Ik (see note 2)
±18mA
Static discharge voltage (HMB)
500V
Storage temperature T_S
Ambient temperature with
-65°C to +150°C
power applied T_amb
Military
-40°C to +125°C
Industrial
-40°C to +85°C
Package power dissipation PTOT
AC
1000mw
LC
1000mw
NOTES
1. Exceeding these ratings may cause permanent damage.
Functional operation under these conditions is not implied.
2. Maximum dissipation or 1 second should not be exceeded, only
one output to be tested at any one time.
THERMAL CHARACTERISTICS
Package type
ΘJC °C/W ΘJA °C/W
AC
12
36
LC
12
35
14