Symbol Mapper (`symbol_mapper_uc_l`)

Maps an unsigned character symbol to a 32 bit signed integer value.

Design

This symbol mapper component takes an unsigned character input value and selects one of 256 configurable symbol values based on the input.

A block diagram representation of the implementation is given in Figure 327:.

Block diagram outlining symbol mapper implementation. — Figure 327: Symbol mapper implementation.

If the input value is larger than the number of symbols the output will be the symbol stored at index 0.

Interface

<?xml version="1.0"?>
<componentspec>
  <property name="length" default="32" parameter="true" type="uchar" description="Number of symbols."/>
  <!-- LINT EXCEPTION: xml_012: 3: Cannot specify default value on an
       array due to test failing -->
  <property name="symbols" type="long" arraylength="length" writable="true"
    description="Array of output symbol values where input is the index."/>
  <port name="input" producer="false" protocol="uchar_timed_sample-prot"/>
  <port name="output" producer="true" protocol="long_timed_sample-prot"/>
</componentspec>

Ports

Inputs:

input: Primary input samples port.
- Protocol: uchar_timed_sample-prot
- Optional: False

Outputs:

output: Primary output samples port.
- Protocol: long_timed_sample-prot
- Optional: False

Opcode Handling

The symbol mapper function is applied on data with sample opcodes only.

As the output data type is larger than the input data type, messages may be split to ensure no output messages are longer than the maximum supported message length of the protocol.

All other opcodes pass through this component without any effect.

Properties

length: Number of symbols.
- Type: uchar
- Access:
  - Parameter: True
  - Writable: False
  - Initial: False
  - Volatile: False
- Default value: 32
symbols: Array of output symbol values where input is the index.
- Type: long
  - Array dimensions: ['length']
- Access:
  - Parameter: False
  - Writable: True
  - Initial: False
  - Volatile: False
- Default value: None

Implementations

symbol_mapper_uc_l (HDL)
symbol_mapper_uc_l (RCC)

Example Application

<?xml version="1.0"?>
<application done="file_write">
  <instance component="ocpi.core.file_read" connect="symbol_mapper_uc_l">
    <property name="filename" value="input.bin"/>
  </instance>
  <instance component="ocpi.comp.sdr.communication.symbol_mapper_uc_l" connect="file_write">
    <property name="length" value="32"/>
    <property name="symbols" value="0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31"/>
  </instance>
  <instance component="ocpi.core.file_write">
    <property name="filename" value="output.bin"/>
  </instance>
</application>

Dependencies

The dependencies to other elements in OpenCPI are:

Protocol interface delay (narrow to wide) primitive v2

There is also a dependency on:

ieee.std_logic_1164

ieee.numeric_std

Limitations

Limitations of symbol_mapper_uc_l are:

The HDL implementation does not use RAM to store symbols. For efficient resource usage and fast timing the number of symbols should be kept appropriately small for the FPGA.

Testing

Tested platforms: None

Component testing not completed.

Symbol Mapper (symbol_mapper_uc_l)