Page 1
dsPICDEM™ 1.1
DEVELOPMENT BOARD
3.3V RETROFIT
© 2005 Microchip Technology Inc. 3.3V Retrofit Rev 1.0-page 1
Modification Instructions
1.1 DSPICDEM 1.1 DEVELOPMENT BOARD 3.3 VDC RETROFIT
This retrofit allows the dsPICDEM 1.1 Development Board (DM 300014, PCB
Assembly 02-01719) to be used as a development tool for both dsPIC30F and
dsPIC33F devices. The development board is modified to replace the digital voltage
regulator, remove the analog voltage regulator and replace transceiver chips with
substitute components that support a wider range of operation (2.8–5.5 VDC).
After completing this modification you will be able to interchangeably work with 3.3 VDC
or 5 VDC devices by simply adding or removing the jumper on the voltage regulator
miniature board.
Other development boards that support both dsPIC30F and dsPIC33F devices include:
• dsPICDEM™ 80-Pin Starter Development Board (Part # DM300019)
• Explorer 16 Development Board (Part # DM240001)
If you have, or wish to purchase, one of these boards you probably don’t need to retrofit
your dsPICDEM 1.1 Development Board.
If you do modify an existing dsPICDEM 1.1 Development Board, you are responsible
for maintaining good workmanship practices. To avoid damage to the printed circuit
board, it is strongly recommended that components be removed by first cutting the
leads and then unsoldering the remaining lead remnants.
Contact your sales representative or DSCD marketing for additional information.
Note: The LCD is not currently supported when 3.3 VDC operation is selected.
THE DSPICDEM 1.1 DEVELOPMENT BOARD 90-DAY WARRANTY WILL EXPIRE
IF YOU MODIFY THE BOARD (REGARDLESS OF WHETHER YOU USE THESE
MODIFICATION INSTRUCTIONS OR PERFORM YOUR OWN MODIFICATIONS).
THE MODIFICATION INSTRUCTIONS ARE SUPPLIED BY MICROCHIP "AS IS".
MICROCHIP DOES NOT WARRANT THAT THE OPERATION OF THE
DEVELOPMENT BOARD, ITS FIRMWARE OR SOFTWARE WILL BE ACCURATE,
UNINTERRUPTED OR ERROR-FREE.
It is your responsibility to ensure that the board continues to function properly and any
application you develop meets your specifications.
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dsPICDEM™ 1.1 Development Board 3.3V Retrofit
3.3V Retrofit Rev 1.0-page 2 © 2005 Microchip Technology Inc.
1.1.1 What You Need
The following table lists the parts you need for this modification. Except for the
RS422 Transceiver used with the RS-485/RS-422 port, all these parts are contained in
a retrofit kit.
Item
Ref.
Des.
Qty Description Value Mfg Mfg Part #
Parts on dsPICDEM 1.1 Development Board
1 U1,U3 2 IC SMT, Driver, RS232 Xmtr/Rcvr,
16-SOIC(wide)
—
MAXIM MAX3232CDWR
2 U12 1 IC SMT, 3.3V CAN TX/RX, 8P
SOIC (0.150")
—
TI SN65HVD230DR
3U41RS422
(See Note 1)
—
MAXIM MAX3491ECSD
Parts on Regulator Adapter Board
4 VR1 IC Positive Adj Regulator TO-263
—
National
Semi
LM317S
5 J1 1 2 Pin.100, SMT header
—
Samtec
TSM-102-01-S-DV
6 R1 1 Resistor, 1206 412R Rohm MCR18EZHF4120
7 R2 1 Resistor, 1206 249R Rohm MCR18EZHF2490
8 R3 1 Resistor, 1206 294R Rohm MCR18EZHF2940
9 1 PCB Assembly
—— —
10 3 Jumper wire
—— —
1: This part is not supplied in the retrofit kit. The RS422 Transceiver will only need to be
replaced if your application uses this feature with 3.3 VDC operation.
Note: The modification kit does not include a dsPIC33F device. It must purchased
separately.
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Modification Instructions
© 2005 Microchip Technology Inc. 3.3V Retrofit Rev 1.0-page 3
1.2 OVERVIEW OF MODIFICATION
Figure 1 provides an overview of what you need to do to complete this modification.
Before proceeding, read the step-by-step procedures carefully to avoid damaging the
dsPICDEM 1.1 board or any of the components.
Figure 1: dsPICDEM 1.1 Retrofit Process
1.3 STEP-BY-STEP PROCEDURES
1.3.1 Step One: Replace CAN Transceiver
1. Remove existing CAN chip U12 by cutting the leads and discarding the chip.
2. Carefully unsolder each lead remnant.
3. Install the TI SN65HVD230DR transceiver chip included.
Note: Be sure to align pin 1 on the chip to pin 1 on the board.
1.3.2 Step Two: Replace UART Transceivers
1. Remove existing UART chips U1 and U3 (and, optionally, RS422 chip U4, by
cutting the leads and discarding the chip.
2. Carefully unsolder each lead remnant.
3. Solder the MAX3232CDWR transceiver chips into reference designator locations
U1 and U3. If appropriate, solder the MAX3491ECSD transceiver chip into reference designator location U4.
Note: Be sure to align pin 1 on the chip to pin 1 on the board.
Step Two: Replace UART
Transceivers U1 & U3 with the
MAX 3232 chips in the retrofit
kit. Optionally, replace RS422
Transceiver U4 with MAX
3491 chip.
CAUTION
To avoid damage to the PCB, remove components by
cutting the leads. Then carefully unsolder each lead.
Step One: Replace CAN
Transceiver U12 with the
SN65HVD230DR chip in the
retrofit kit.
Step Three: Replace the digital voltage regulator (VR1)
with the miniature PCB assembly (refer to step-by-step procedures).
Step Four: Remove the analog
voltage regulator (VR2).
Step Five:
Install jumper wire from the
plus end of C18 to the closest
end of L1 to bypass analog reg-
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dsPICDEM™ 1.1 Development Board 3.3V Retrofit
3.3V Retrofit Rev 1.0-page 4 © 2005 Microchip Technology Inc.
1.3.3 Step Three: Replace Voltage Regulator VR1
1. Cut the leads on the digital voltage regulator chip (VR1), then unsolder the chip
from its heat sink pad.
2. Unsolder the lead remnants.
3. Install the miniature regulator board:
• Solder the miniature board to the dsPICDEM 1.1 board at the four solder points
shown in Figure 2. Be sure the PCB assembly does not overlap the V
IN and
VOUT pads. Use a HOT iron to ensure good solder flow through the holes.
• Add jumper wires for VIN and VOUT.
4. Place the regulator on the heat sink pad on the miniature regulator board, aligning
the pins with the soldering pads and leaving a small area of the heat sink exposed
near the regulator's tab (approximately 1.25 mm), as shown in Figure 3.
5. Solder the three regulator leads. Then solder the regulator tab to the exposed area
of the heat sink.
1.3.4 Step Four: Remove Voltage Regulator VR2
1. Cut the three leads on regulator VR2.
1. Unsolder the tab to remove the regulator chip.
2. Unsolder the lead remnants.
3. Leave the VR2 socket empty.
1.3.5 Step Five: Install VR2 Bypass Jumper
1. Solder one end of wire jumper to the end of L1 closest to the LCD (see Figure 4).
2. Solder the other end to the + side of C18
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Modification Instructions
© 2005 Microchip Technology Inc. 3.3V Retrofit Rev 1.0-page 5
Figure 2: Installing the Regulator Miniature Board
Figure 3: Installing the Regulator Chip
Figure 4: Regulator VR2 Bypass Jumper
L2
VR1
POWER
C8
R1
Solder points
VIN Jumper
V
OUT Jumper
Jumper for 5V operation
(removed for 3.3V operation)
Note corner alignment
Outline of regulator circuit
Heat sink pad
Leave space between the
miniature PCB assembly and
the pads for the V
IN and VOUT
leads to prevent shorting.
Tab
Heat sink pad
Solder regulator leads to board
Solder regulator tab to heat sink
pad. Leave 1.25 mm gap between
tab and silk screen edge
LCD1
C18
L1
AVDD
AGND
VR2
LED1
LED2 LED3 LED1
RP1 RP2 RP3
Solder jumper between + side of C18
and end of L1 closest to LCD1
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dsPICDEM™ 1.1 Development Board 3.3V Retrofit
3.3V Retrofit Rev 1.0-page 6 © 2005 Microchip Technology Inc.
1.4 USING THE BOARD
To use the board with +5 VDC devices, install the regulator jumper (see Figure 5).
To use the board with +3.3 VDC devices, remove the regulator jumper.
Figure 5: Regulator Jumper
1.5 SCHEMATIC DIAGRAM
Figure 6 is a schematic of the digital voltage regulator replacement circuit.
Figure 6: dsPICDEM 1.1 Development Board 3.3V Modification
Note: Remember that the LCD is inoperable when the board is used at 3.3 VDC.
5V Operation — Jumper installed
3.3V Operation — Jumper removed
IN OUT
ADJ
VIN
VOUT
VR1
LM317S
J1
R1
412R
R2
R3
249R
294R
3
1
2
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