Base convert

Base Convert Rev A

Introduction

Base Convert PL-47710 Rev. A is a simple desk/handheld device to convert between hexadecimal, decimal, and binary. The unit features separate displays for each number base for easy comparison between the three bases. User input is possible using 16 alphanumeric keys and an input mode selector switch. The device is powered by 4 AA alkaline batteries with an estimated 100 hours of battery life.

Specifications

Layout

1. Hexadecimal Display
2. Decimal Display
3. Binary Display
4. Power and Input Selection Switch
5. Alphanumeric Input Keypad
6. Programming Port (Right Angle Header on Side)

Installing Batteries

Using a 1.5mm hex bit remove the eight M2.5 button head hex bolts holding the back panel to the unit. Install 4x AA batteries into the battery holder attached to the main PCB. Follow the polarity imprinted on the battery holder. The device does have reverse polarity projection that should project it from damage but it is still advisable to not reverse the polarity of the batteries. Replace the back panel after installing the batteries.

Use

To turn on the unit slide the selector switch from the OFF position to any of the three input positions. The display will illuminate at the default value of 0.

To Input Hexadecimal Number

Slide the selector switch to HEX. The right most decimal on the hexadecimal display will illuminate when the unit is in hexadecimal input mode. Use the alphanumeric keypad to input a hexadecimal number, all three displays will update after each key press. If the hexadecimal number exceeds 4 digits the left most digit will be dropped to shift in the right most digit. Clearing the display by pressing the CLEAR button will set the hexadecimal number to 0.

To Input Decimal Number

Slide the selector switch to DEC. The right most decimal on the decimal display will illuminate when the unit is in decimal input mode. Use the alphanumeric keypad to input a decimal number, all three displays will update after each key press. If the decimal number will exceed 65,535 with the requested key press the device will no longer shift in new decimal digits while in decimal input mode. Clearing the display will set the decimal number to 0.

To Input Binary Number

Slide the selector switch to BIN. There is no indicator on any of the displays to indicate that the unit is in binary input mode. Use the alphanumeric keypad to toggle the bits of the binary number displayed on the binary display, all three displays will update after each key press. Pressing the CLEAR button will set the binary number to 0.

Updating Firmware

It is possible to update the firmware. A TI Launchpad and cable is required. The pin out of the programming header is as follows when looking at the unit from the front.

• 3.3V
• SBWTDIO
• SBWTCK
• GND

External power is required, install 4x AA batteries before updating the firmware and place the selector switch in any of the input positions.

The most current firmware is located here: https://github.com/sdp8483/base_convert/tree/master/firmware/base_convert CCS 8.x.x or newer is required to update the firmware. Please search online for help using CCS and uploading firmware since this is outside of the scope of this document.

Future Fixes

• Silkscreen label of programming interface connections/pins
• Silkscreen label of power connector + and - pins
• add space for solder iron around resistor networks
• battery low indicator in SW, should have HW to do it
• at 6V the display will not turn off when the PNP are pulled high (cant pull it high enough) Placing a 1k resistor between the base and emitter of each PNP solves the problem but it appears like there is an issue caused with the 3.3V LDO since the voltage to the uC is 4.1V or so not the 3.3V it should be. Going to see if 3V for the battery is bright enough and maybe switch to 2AA as battery or go to LiPo in the future.
• Swap C2 and C4 on PCB so that the correct capacitor is near the correct IC
• Easy firmware update method --LOW PRIORITY