uM-FPU V2 Floating Point Coprocessor

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uM-FPU V2 Application Notes


The uM-FPU V2 floating point coprocessor is easily interfaced with virtually any microcontroller to provide support for 32-bit IEEE 754 compatible floating point and 32-bit long integer calculations. It can be connected using either an I2C or SPI compatible interface. The uM-FPU uses an internal oscillator and requires no external components. It is available in an 8-pin DIP or SSOP-20 SMT package. Documentation and support software is available for a variety of microcontrollers.

Suggested Retail Price: $14.95 USD


  • 8-pin integrated circuit.
  • I2C compatible interface up to 400 kHz
  • SPI compatible interface up to 4 Mhz
  • 32 byte instruction buffer
  • Sixteen 32-bit general purpose registers for storing floating point or long integer values
  • Five 32-bit temporary registers with support for nested calculations (i.e. parenthesis)
  • 32-bit Floating Point Operations
    • Set, Add, Subtract, Multiply, Divide
    • Sqrt, Log, Log10, Exp, Exp10, Power, Root
    • Sin, Cos, Tan
    • Asin, Acos, Atan, Atan2
    • Floor, Ceil, Round, Min, Max, Fraction
    • Negate, Abs, Inverse
    • Convert Radians to Degrees, Convert Degrees to Radians
    • Read, Compare, Status
  • 32-bit Long Integer Operations
    • Set, Add, Subtract, Multiply, Divide, Unsigned Divide
    • Incrment, Decrement, Negate, Abs
    • And, Or, Xor, Not, Shift
    • Read 8-bit, 16-bit, and 32-bit
    • Compare, Unsigned Compare, Status
  • Conversion Functions
    • Convert 8-bit and 16-bit integers to floating point
    • Convert 8-bit and 16-bit integers to long integer
    • Convert long integer to floating point
    • Convert floating point to long integer
    • Convert floating point to formatted ASCII
    • Convert long integer to formatted ASCII
    • Convert ASCII to floating point
    • Convert ASCII to long integer
  • User Defined Functions can be stored in Flash Memory
    • conditional execution
    • table lookup
    • Nth order polynomials

Pin Descriptions

 Pin   Name  Type  Description
1  CS  Input   Select
2  SOUT  Output  SPI Output
 Input  SPI Clock
 I2C Clock
4  VSS  Power  Ground
5  SIN
 SPI Input
 I2C Data
6  TSTOUT   Output  Test Output
7  TSTIN  Input  Test Input
8  VDD  Power  Supply Voltage 

See also: SMT Pinout and Package Specifications.


uM-FPU V2 Datasheet
Functional description and hardware specifications.
560 KB PDF Jun 21, 2005
uM-FPU V2 Instruction Set
Detailed descriptions for each instruction.
644 KB PDF Aug 16, 2006

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