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Chapter 4: Hardware Descriptions
The circuit is designed in such way that the value of all resistors and capacitors are not critical.
4.1 LEDs:
The P3.2, P3.3, P2.5, P2.4 are connected to the LED0-LED3 via a buffer (U8). In order to turn
on an LED, you need to program the corresponding pin as output and set it high.
4.2 Push button switches:
The P4.4, P4.2, P4.0, P6.1 are connected to the 4 push buttons, SW2-SW5.
4.3 Light sensor (AN0)
The light sensor (a TEMP4452 or equivalent) is connected to the PE1 (AIN2) of the ADC port.
4.4 Potentiometer (AN1)
The 5K potentiometer VR2 is connected to the PE2 (AIN1) of the ADC port
4.5 Temperature sensor (AN2)
The temperature sensor (LM45 or equivalent) is connected to the PE5 (AIN8) of the ADC port
4.6 Speaker
The speaker is a 5V audio magnetic transducer and it’s driven by the PC4, a timer, or by the
DAC output from U17 (MCP4725). The signal source of the speaker is selected by the jumper
J24.
4.7 Serial I2C EEPROM
A small serial EEPROM (24LC02) is provided for experimenting with I2C communication.
4.8 UART communication
When P3.2 and P3.3 are not used for the Lab assignment #1 (see above paragraph #4.1 and
#4.2) or not used for driving the onboard H-Bridge, they can be used as a UART.
The UART can be used by user’s application programs. It supports direct 3.3V digital signal
interface with other boards, or use a 3V USB serial adapter (a FTDI cable) for interfacing with a
PC.
