TMS0803 scientific calculator emulated on MSP430G2452

simpleavr got inspired with web based calculator emulator and so he decided to build his own hardware based emulator. He’s chosen MSP430G2452 microcontroller (same that comes with launchpad) to run emulation. He tried to match original calculator layout and speed by selecting MCU clock speed. To make it look more retro he used bubble LED seven segment indicators. After several PCB versions it seems that he finally made it. Continue reading

MSP430 frequency counter uses 8 seven segment displays

MSP430 frequency counter

This frequency counter is practically classic example of MCU based device. It captures frequency pulses directly to MCY pin without any special prescalling circuitry or even protection. So it is capable to accept 3.3V CMOS level signals. But it is designed as module which can be integrated in to end device if needed. The counting workload is done by MSP430G2202 microcontroller which is capable to count up to 10MHz signals. The display is connected to microcontroller using transistor based column selector decoded by 74HC238 and rows driven by MCU pins. One interesting feature included in this project is that counter can be calibrated to achieve +-10Hz error at 10MHz.   Continue reading