comtech aha corporation
PS4501_0501
A subsidiary of Comtech Telecommunications Corporation
i
Table of Contents
1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Conventions, Notations and Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.0 Functional Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1 Data Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.4 Feedback. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.5 Data Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.6 Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.6.1
Encode Synchronization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.6.2
Decode Synchronization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.6.3
Resynchronize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.7 Helical Interleaving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.8 Data Throughput . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.9 Encoding/Decoding Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.10 Summary of Channel Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.11 Latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.12 Microprocessor Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.0 Internal Register Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1 Configuration 0, Address 0x00 - Read/Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2 Configuration 1, Address 0x01 - Read/Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3 Configuration 2, Address 0x02 - Read/Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.4 Feedback, Address 0x03 - Read/Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.5 Quantization, Address 0x04 - Read/Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.6 Corrections, Address 0x05 - Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.7 Synchronization, Address 0x05 - Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.8 Status, Address 0x06 - Read Only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.9 Control/Interrupt, Address 0x07 - Read/Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.10 Reserved, Address 0x08 - Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.0 Performance Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.0 Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1 System Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.2 Microprocessor interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.3 Input Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.4 Output Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.0 Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.0 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.1 Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.2 Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.2.1
DC Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.2.2
Test Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.2.3
Pin Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.0 Timing Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
9.0 Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
10.0 Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.1 Available Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.2 Part Numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
11.0 Related Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
comtech aha corporation
ii
A subsidiary of Comtech Telecommunications Corporation
PS4501_0501
Figures
Figure 1:
Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Figure 2:
IDATA Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Figure 3:
Input Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 4:
2D Interleaving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 5:
Encoded/Interleaved Data Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 6:
Encoding at the Maximum Input Rate (bit/clock) with Maximum Output Rate (bit/clock). . . . . . . . . . . . . . . 7
Figure 7:
Encoding at Less Than Maximum Input Rate with Maximum Output Rate . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 8:
Decoding with Continuous Input Data Rate - STITER not Asserted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 9:
Decoding with Burst Input Data Rate - STITER not Asserted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 10: Decoding with Burst Input Data Rate - STITER Asserted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 11: DUMP Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 12: Turbo Product Code vs. Reed-Solomon/Viterbi Performance Comparison . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 13: Comparison of TPC Code Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 14: Performance Curve of E
b
/N
o
for BER of 10
-5
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 15: Pinout 100 MQFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 16: Current vs. Data Rate (typ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 17: Signal Timing vs. Output Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 18: Data Input Timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 19: Data Output Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 20: Microprocessor Interface Timing (Write); PROCMODE=0, MUXMODE=0 . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 21: Microprocessor Interface Timing (Read); PROCMODE=0, MUXMODE=0 . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 22: Microprocessor Interface Timing (Write); PROCMODE=0, MUXMODE=1 . . . . . . . . . . . . . . . . . . . . . . . . 30
Figure 23: Microprocessor Interface Timing (Read); PROCMODE=0, MUXMODE=1 . . . . . . . . . . . . . . . . . . . . . . . . 31
Figure 24: Microprocessor Interface Timing (Write); PROCMODE=1, MUXMODE=0 . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 25: Microprocessor Interface Timing (Read); PROCMODE=1, MUXMODE=0 . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 26: Interrupt Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 27: Clock Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 28: Power On Reset Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 29: AHA4501 Package Specifications 100 MQFP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
comtech aha corporation
PS4501_0501
A subsidiary of Comtech Telecommunications Corporation
Page 1 of 37
1.0
INTRODUCTION
The AHA4501 is the first single-chip Forward
Error Correction LSI device using Turbo Product
Codes (TPC). The device operates as a block code
encoder at the input or a block code decoder at the
output of a communication channel. The device
supports various programmable features, such as
block size, codes and code rates, to optimize various
communication channel needs for error
performance and data throughput. Turbo Product
Codes offer a higher performance alternative to
Reed-Solomon or Reed-Solomon concatenated
with Viterbi error correction methods.
When encoding, the device appends the Error
Correction Code (ECC) bits to the blocks, and
outputs the encoded blocks. When decoding, the
device accepts soft decision values and stores the
data as a block in its internal RAM. The block is
then decoded iteratively by running it through the
device's soft in/soft out (SISO) decoder. The device
iterates to the maximum programmed iteration
limit. The decoded block is then output through the
device output data port.
This specification describes the functional
operation, programming, timing and ordering
information. Please contact AHA for additional
support material, including evaluation software and
relevant technical publications; or visit our website
at http://www.aha.com.
1.1
CONVENTIONS, NOTATIONS AND
DEFINITIONS
Code block A data stream to be encoded or
decoded is segmented into blocks for processing
by the AHA4501. Data in a code block is
configured as a 2D or 3D array.
Axis iteration Decoding one axis of an array (all
x rows, all y columns, or all z columns).
Full iteration Decoding all axes of an array (all
rows and columns).
Soft value Input to the decoder from either an
Analog/Digital Converter(ADC) or digital
demodulator.
Code rate Ratio of the number of data bits to the
number of data and ECC bits.
Data rate The rate at which unencoded data is
input to the device when encoding or output from
the device when decoding.
Channel Rate The rate at which encoded data is
output from the device when encoding or input to
the device when decoding. Note that system
channel rate may be different due to external
synchronization marks or other overhead.
Original Array (OA) The soft decision input data
array. Data is stored as a 6 bit soft value per location
to support the maximum 6 bit input quantization.
Intermediate Storage Array (ISA) The storage
array for data between iterating.
Hard Decision Array (HDA) The hard decision
output. Data is stored as one bit per location.
(n
1
,k
1
)x(n
2
,k
2
) A general representation of a 2D
block code for use in the descriptions to follow in
this specification. For example, in a
(64,57)x(64,57) code; n
1,
n
2
=64 represents the
length of the data + ECC bits, and k
1
,k
2
=57
represents the length of only the data bits. 3D
codes are represented as (n
1
,k
1
)x(n
2
,k
2
)x(n
3
,k
3
)
Vector One row or column of data in a block.
Latency The time from the first bit of a block in
to first bit of the same block out.
Active low signals have an "N" appended to the
end of the signal name. For example, MCSN and
RESETN.
Hex values are represented with a prefix of "0x",
such as register "0x00". Binary values do not
contain a prefix.
1.2
FEATURES
PERFORMANCE:
Maximum 50 Mbits/sec channel rate encoding
36.5 Mbits/sec channel rate decoding for a 64x57
square code at two iterations
Two or more devices can be used in parallel to
increase throughput
Optional "helical" interleaving (encoding) and
deinterleaving (decoding)
FLEXIBILITY:
Internal buffering allows continuous data
streaming
Programmable block size from 256 to 4096 bits
Two or three dimensional blocks
Programmable number of iterations per block up
to 32
Programmable quantization up to 6-bits for soft or
hard decision input data (decoding)
Support for external synchronization
SYSTEM INTERFACE:
Serial or 8-bit parallel input and output data ports
Selectable microprocessor interface for Intel or
Motorola processors
Control Commands for: Decode, Encode, Soft
Reset, Resynchronize and Dump Current Block
System Interrupts include Block Decode Complete,
Block Correction Incomplete, Sync Mark Mismatch
Number of corrections per block accumulated in
an internal register
OTHERS:
3.3 Volt operation
100 pin quad flat package
Output signals may be tristated to facilitate board
level testing
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