Hardware Description
©
2011 Microchip Technology Inc.
DS51994A-page 9
1.3
ANALOG INPUT STRUCTURE
Two differential input paths allow external signal sources to be easily connected to the
MCP3903 input. Edge connectors JP1 and JP2 are 3-pin connectors that act both as
crew-type and clip-on post connectors.
JP1 and JP2 can be used to force either channel from a differential to a single-ended
configuration. R3 and R4 (on CH0), and R1 and R2 (on CH2) act as locations for
burden resistor connectors for any current transformer inputs.
1.4
USB TO SERIAL CONVERTER
The MCP3903 ADC Evaluation Board for 16-Bit MCUs also contains a USB connection
for connecting the evaluation board to a PC. On the board, there is an MCP2200 USB
to UART converter that creates a virtual COM port on the PC. The MCP3903 ADC
Evaluation Board for 16-Bit MCUs also features a RS232 connector just in case it is
required. The RS232 Line driver is connected to the same UART pins of the MCU. For
this reason, a 3-pin jumper (J5) is present on the evaluation board to select which serial
communication will be used: USB or RS232. The following figure summarizes the
connections between the ADC, MCU, USB to serial converter and RS232 line driver.
FIGURE 1-5:
Serial Communication Block Diagram.
Note:
To use an edge connector as a post connector, pull up the blue plastic top
to access the posts.
PIM
Module
USB
TX
RX
MCP2200
ADC
MCP3903
RF6/SCK1
RF7/SDI1
RF8/SDO1
SCK
SDO
SDI
RS232 Driver
USB con
RS232
TX
RX
RF2/U1RX
RF3/U1TX
