3-component circuit accurately measures temperatures

The inexpensive circuit in EDN BBS /DI_SIG #1419 accurately measures temperatures using NTC thermistors. The circuit requires two bidirectional CMOS I/O pins of a mC or expansion port. The circuit employs a precision resistor and a capacitor in addition to the thermistor.

Display decoder works upside down

The 22V10 PLD program for a hex-to-7-segment converter in EDN BBS /DI_SIG #1404 has an unusual feature: The converter can display digits either right side up or upside down.

Utility freezes FPGA pin locations

The C utility FREEZEPN in EDN BBS /DI_SIG #1405 takes a Xilinx field-programmable gate-array (FPGA) (XC3000 and XC4000 series) fitter file (APR or PPR) and creates a design-constraints file (.CST) to freeze pin locations or pin and CLB locations.

Method quickly computes square roots

The algorithm in EDN BBS /DI_SIG #1406 computes single-precision floating-point square roots using only integer-multiply and shift instructions, yielding results five times faster than library routines do.