GPS Location Saving System Hardware Review

GPS LOCATION SAVING SYSTEM HARDWARE

REVIEWWWU

Taylor Reijm

GPS Location Saving System Full Schematic

NXP LPC2378 ARM7 MCU

LPC2378•32-bit MCU•512kB Flash Memory•144-pin•20MHz oscillator•Used to control TFT touch screen LCD and LCD controller.•1 GPIO used for automatic power off circuitry•RXD3 and TXD3 used to interface with GPS Receiver.

Power Supply Circuitry

•7.2V NiMH battery with 3000mA hrs.•IRFZ44N VGS=2V to start conduction.•VGS=0V to end conduction.•GPIO and SW2 used to control conduction•ATPS006A0X Pico TLynx DC-DC switching power module.

• Fixed Switching Frequency• Remote On/Off• 4.5Vdc-14Vdc• 6A

•Trim resistance used to get output of 5V• RTRIM=[5.91/(Vo -0.591)]k ohms• RTRIM(5V)=1.34k ohms

NCP1117•18V max in•3.3V out•800mA output current

TFT LCD and Controller

ADS7843- Touch screen controller•12 bit ADC with synchronous serial interface•Comes connected as shown from Gravitech

ELT240320TP-TFT LCD•Thin Film Transistor Touch screen interface•2.8” screen 240x320 pixels.•Backlight control•Cap Sense O/P

Reset Circuitry

•Active low reset

Oscillator and EEPROMOscillator•20MHz oscillator with enable tied to 3.3V supply

EEPROM•8kB•I2C interface w/LPC2378

GPS Receiver

EM-406A• 4800 baud NMEA 0183 output• 4.5V~6.5V DC input supply• ~44mA • O/P voltage level 0V to 2.85V• One Pulse Per Second not used.