MIKROE-455 mikroElektronika, MIKROE-455 Datasheet - Page 12

• Manufacturer Part Number: MIKROE-455
• Description: Development Boards & Kits - 8051 EASY8051 V6 DEVELOPMENT SYSTEM
• Manufacturer: mikroElektronika

Specifications of MIKROE-455

• Rohs: yes
• Product: Development Kits
• Tool Is For Evaluation Of: AT89S8253
• Core: 8051
• Interface Type: CAN, MMC/SD, RS-232, USB
• Operating Supply Voltage: 5 V, 9 V to 32 V
• Data Bus Width: 8 bit
• Description/function: Development Board Only, GLCD, LCD, DS1820, Serial Cable not included
• Dimensions: 265 mm x 220 mm
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• For Use With: AT89S8253

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Easy8051 v6 Development System
7.0. A/D Converter
An A/D converter is used for converting an analog signal into the appropriate digital value. A/D converter is linear, which means that the
converted number is linearly dependent on the input voltage value. The Easy8051 v6 development uses the MCP3204 circuit as an
A/D converter. Voltage to be converted is brought to the input pins of this circuit which then converts it into a 12-bit digital value. Such
number is transferred to the microcontroller via serial communication, while switches 1, 4, 5 and 6 on the DIP switch SW6 should be
set to the ON position. Voltage provided on the A/D converter input pins can be either power supply voltage (5V) or external voltage
brought to the converter via CN12 and CN13 connectors. When the power supply voltage is used, it is necessary to determine which
of the following pins CH0, CH1, CH2 or CH3 is to be supplied with such voltage using jumper J12. In this case, the voltage value on the
A/D converter input can vary between 0V and 5V using potentiometer P3. When the external voltage is used, it is necessary to remove
jumpers J12 in order to prevent voltage interference and provide conversion accuracy. The MCP3204 circuit includes the Vref pin to
receive voltage reference. However, the main purpose of this pin is to determine the range of analog voltage to be converted, hence the
A/D conversion resolution. Jumper J10 is used for selecting one of two possible voltage reference sources. When this jumper is in the
VCC position, the value of the voltage reference is 5V, whereas it amounts to 4.096V when the jumper is set to the position referred to by
4.096. The latter is generated by the MCP1541 circuit.
Figure 7-1: ADC (jumper default position)
Figure 7-2: Pin CH0 used as A/D conversion input
A/D conversion is performed via the CH0 pin on A/D convertor
Figure 7-3: Microcontroller and A/D converter test inputs connection schematic
MikroElektronika