Microchip Technology DM300024 Data Sheet
dsPICDEM™ 1.1 Development Hardware
©
2006 Microchip Technology Inc.
DS70099D-page 63
5.1.3
RS-485/RS-422 Port
Signals for the RS-485/RS-422 port are available on the 6-pin terminal block labeled
TB1. The terminal block can be reconfigured from RS-485 to RS-422 by removing the
jumper on J7. Inserting jumper J6 will terminate the bus with a 120-ohm resistor.
TB1. The terminal block can be reconfigured from RS-485 to RS-422 by removing the
jumper on J7. Inserting jumper J6 will terminate the bus with a 120-ohm resistor.
The RX485 and TX485 lines of the MAX3491E can be tied to the dsPIC DSC UART
channel 1 U1RX and U1TX pins by moving the jumper on J4 to the TX485/RX485
position.
channel 1 U1RX and U1TX pins by moving the jumper on J4 to the TX485/RX485
position.
MAX489E receiver and driver output enables are controlled by port pins RG0 and RG1,
respectively.
respectively.
The RS-485 and RS-422 port schematic is shown in Figure A-5: “dsPICDEM™ 1.1
Plus Development Board Schematic (Sheet 4 of 5)”.
Plus Development Board Schematic (Sheet 4 of 5)”.
5.1.4
Temperature Sensor
Temperature sensor U9 is a -40°C to +125°C linear output TC1047A connected to
analog channel AN8 of the dsPIC DSC device. The output of the temperature sensor
is fed through a second-order low-pass filter before connection to the dsPIC DSC
device. The low-pass filter cutoff frequency is set at 10 Hz. The output voltage range
for the TC1047A is typically 750 mV at +25°C. The TC1047A exhibits a typical 10 mV/C
voltage slope.
analog channel AN8 of the dsPIC DSC device. The output of the temperature sensor
is fed through a second-order low-pass filter before connection to the dsPIC DSC
device. The low-pass filter cutoff frequency is set at 10 Hz. The output voltage range
for the TC1047A is typically 750 mV at +25°C. The TC1047A exhibits a typical 10 mV/C
voltage slope.
The schematic of the temperature sensor is shown in Figure A-4: “dsPICDEM™ 1.1
Plus Development Board Schematic (Sheet 3 of 5)”.
Plus Development Board Schematic (Sheet 3 of 5)”.
5.1.5
Analog Potentiometers
Three 5 kOhm potentiometers are connected to analog channels AN4 (RB4), AN5
(RB5) and AN6 (RB6). The voltage output range for each potentiometer is between 0V
DC and 5V DC. The voltage source is provided by VR2, which is a separate voltage
source for all the analog components on the development board.
(RB5) and AN6 (RB6). The voltage output range for each potentiometer is between 0V
DC and 5V DC. The voltage source is provided by VR2, which is a separate voltage
source for all the analog components on the development board.
The schematic of the analog potentiometers is shown in Figure A-4: “dsPICDEM™
1.1 Plus Development Board Schematic (Sheet 3 of 5)”.
1.1 Plus Development Board Schematic (Sheet 3 of 5)”.
5.1.6
Push Button Switches
Switches SW1-SW4 are connected to port pins RA12-RA15, respectively, on the dsPIC
DSC device. The signal lines are normally pulled up to +5V DC through 10 kOhm resis-
tors. Pressing the switch will short the line to ground. Port pins RA12-RA15 are config-
ured as the INT1-INT4 external interrupt pins.
DSC device. The signal lines are normally pulled up to +5V DC through 10 kOhm resis-
tors. Pressing the switch will short the line to ground. Port pins RA12-RA15 are config-
ured as the INT1-INT4 external interrupt pins.
The schematic of the push button switches is shown in Figure A-4: “dsPICDEM™ 1.1
Plus Development Board Schematic (Sheet 3 of 5)”.
Plus Development Board Schematic (Sheet 3 of 5)”.
5.1.7
LEDs
Four red LEDs, LED1-LED4, are connected to port pins RD0-RD3, respectively, on the
dsPIC DSC device. The LED anodes are tied to V
dsPIC DSC device. The LED anodes are tied to V
DD
through a 1.2 kOhm resistor.
The schematic of the LEDs is shown in Figure A-4: “dsPICDEM™ 1.1 Plus Develop-
ment Board Schematic (Sheet 3 of 5)”.
ment Board Schematic (Sheet 3 of 5)”.