Data Values

Some module attributes are assigned numeric values. Data values consist of the arithmetic base, or radix, followed by the numeric data value in the specified base. LogiBLOX only allows bases 2, 4, 8, 10, and 16. The default base is decimal and does not need to be specified. The following formats are allowed.

base#value#
decimal_value

For example, the decimal value 17 can be expressed as follows.

The following attributes require a numeric data value.

• Async. Count and Sync. Count
  
  
• Async. Val and Sync. Val
  
  
• C Value
  
  
• Clock Divisor
  
  
• Count Limit
  
  
• Decode Mask
  
  
• Input Buses (decimal value only)
  
  
• Inversion Mask
  
  
• Memory Depth (decimal value only)
  
  
• Output Duty Cycle
  
  

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  NOTE

  The Bus Width attribute also takes a numeric value, but it is restricted to decimal values between 2 and 64, inclusive.

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When a constant value (C Value) is specified, the precision of the value might be less than the precision of the bus; if so, it will be sign-extended on the left (toward the MSB). If the value is greater than the precision of the bus, the higher order bits are ignored. In this case, a warning is also printed.

The following table shows the valid characters for several radices.

Table 3_1 Valid Characters Using Various Base Values

• Numeric data values must contain only characters valid for the specific radix.
  
  
• Negative data values are handled as twos-complement and are represented by a minus sign in front of the data value (for example, -2#0011# = 2#1101# = -3).
  
  
• You can use the underscore character to increase the readability of numbers. The underscore characters have no value and are ignored by the software. For example, the value
  
  2#00010010011100100110011101101001#
  
  is more legible when it is formatted as
  
  2#0001_0010_0111_0010_0110_0111_0110_1001#
  
  
• If the LogiBLOX module contains two or more registered elements, the data values assigned to the Asynchronous Value and Synchronous Value attributes for each element are combined in a single assignment. The intended recipient of each data value is indicated by a token that precedes the data value. The token and data value are separated by a colon, and two token:data value pairs are separated by a period. For example, an Accumulator module may have the following assignment.
  
  OVFL:1.REG:2#1111#
  
  This line assigns a value of 1 to OVFL and a binary 1111 to REG.
  
  Asserting a module's Asynchronous Control or Synchronous Control pin affects all the registers contained within that module.