Universal Development Board Reference Manual

Revised January 15, 2014

This manual applies to REV E of the board.

The Universal Development Board (UDB) is a microcontroller development board intended to use with a wide variety of PIC microcontrollers from Microchip®. It was designed to support most 3.3V, PIC microcontrollers in 8-bit, 16-bit, or 32-bit varieties. It will accommodate a wide range of Microchip PIM processor modules as well as DIP packaged parts with pin counts from 8-pin to 28-pin. Three DIP sockets are provided: 20/14/8 PIN 8-bit PIC, 28 PIN 8-bit PIC, and 28-pin PIC24/dsPIC33/PIC32MX. This board also has discrete I/O elements and 2 Pmod connectors for further device evaluation or product development capability. Expansion connectors are provided that are compatible with the Microchip PICtail™ Plus line of expansion modules. In addition to the PIM connector and DIP sockets, a PIC32MX360 microcontroller is also provided for use without the need for additional PIM or DIP socketed processors. The Universal Development Board is designed to be compatible with the Microchip Explorer 16 development board. The layout of the PIM connector and PICtail™ Plus bus connections are physically and electrically compatible with the Explorer 16, and many Microchip demonstration programs for the Explorer 16 will work with the UDB.

The Universal Development Board is designed to be compatible with the Microchip Explorer 16 development board. The layout of the PIM connector and PICtail™ Plus bus connections are physically and electrically compatible with the Explorer 16, and many Microchip demonstration programs for the Explorer 16 will work with the UDB.

• Microchip® PIC32MX360 microcontroller
• PICTail™ Bus/PIM connector
• ICSP Header
• 20/14/8 Pin 8-Bit PIC
• 28 Pin 8-Bit PIC
• 28 Pin PIC24/dsPIC33/PIC32MX
• Two Pmod Connectors
• Three Push Buttons
• Two Analog POTs
• Eight user LEDs
• USB Serial Convertor
• Power from header or USB Convertor
• 3.3V operating voltage
• 8 MHz Oscillator
• Serial EEPROM

The UDB can be powered in one of two ways, either by a bench supply or a wall wart type power supply attached to the power header, J20; or from the USB connector, J23, associated with the USB serial converter. The UDB is intended to be operated from a regulated 5V power source, however with certain restrictions, a different supply voltage can be used. The absolute maximum voltage that should be applied to the power header is 6V.

If an external power source other than a regulated 5V supply is used, the voltage on the VCC5V0 bus will be the voltage of the external supply, and the test points on the board labeled 5V will actually be at the voltage of the external supply.

To power the board with from the USB use a USB 2.0 A to Mini B cable to connect the PC to the UDB via connector J23. The Jumper at J21 (power select) must be placed in the USB position and the power switch, SW1, must be in the ON position. When the board is powered, the LED at LD8 will be illuminated.

To power the board using an external power supply connected to J20 (EXT Supply 5VDC), the jumper at J21 (Power Select) must be placed on the EXT position. In order for the board to be powered the switch at SW1 must be in the ON position, when the board is powered, the LED at LD8 will illuminate. If SW1 is in the OFF position the UDB is not powered. A fail to power can also occur if the jumper at J21 is in the USB position.

Connector J20 is a two pin header using 100mil spaced, 0.25mil square posts. An MTE style connector or clip leads can be used to supply power to this header. The proper polarity is marked on the board. A Shotkey diode, D5, is provided for reverse polarity protection.

All on-board circuits operate at 3.3V. The primary regulated power bus VCC3V3 is powered by a voltage regulator circuit made up of IC9, a Microchip MCP1703 LDO voltage regulator and the associated input and output capacitors C32, C33 and C34. This regulator is rated for a maximum dropout of 625mV. To ensure that the regulator output is the proper 3.3V, the minimum voltage applied to the input of the regulator should be 4V. Allowing for the forward drop across the reverse polarity protection diode, D5, in the input circuit, the minimum external supply voltage should be 4.4V.

In addition to the main voltage regulator, a second regulator is used to provide power to the USB serial converter circuit. This regulator is made up of IC11, a Microchip TC1014 LDO voltage regulator and the associated input and output capacitors C28 and C29 and bypass capacitor C30. This regulator is always powered from the USB connector J23, and therefore, power is only supplied to the USB serial converter when J23 is connected to a live USB port.

Some Microchip PICtail™ Plus modules require a 9V power supply to power some of their functions. There is no 9V power supply on the UDB board. If a PICtail™ Plus module is being used that requires the 9V power supply, an external, regulated 9V supply can be attached at J5 to provide this voltage. Jumper J5 is an unloaded, two pin header in the upper right corner of the board. Note the polarity marking on the board as it is not internally protected from reverse polarity.

The MCP2200 is a USB-to-UART serial converter which enables USB connectivity in applications that have a UART interface. The serial signals USB-RXD, USB-TXD, USB-CTS, and USB-RTS are available at connector J22, to the right of USB connector J23. The signal names are labeled on the board. Jumper wires can be used to connect the serial interface signals to locations on either the DIP bus or the PIM bus to allow access to the serial interface from a microcontroller in the PIM socket, any of the DIP sockets, or the on-board PIC32MX360.

In order to use the MCP2200 USB serial converter, it is necessary for the appropriate drivers to be installed on the host computer. The necessary drivers as well as a configuration utility and other support software can be downloaded from the MCP2200 product page on the Microchip web site.

Jumper JP10, labeled UART USB RESET on the board, can be used to hold the MCP2200 in reset. Placing a shorting block on JP10 will cause the MCP2200 to be held in reset. This can be useful when using a USB port to power the board and the serial interface isn’t being used. Normally, when the USB cable is connected to a PC, the MCP2200 will be enumerated on the USB bus and the host computer will expect the MCP2200 driver to be loaded. Use of this jumper allows the board to be USB powered without the need for the MCP2200 driver to be installed.

The MCP2200 also has 256-bytes of integrated user EEPROM. There are two LEDs connected to the USB-to-UART serial converter, LD12 which turns on during a transmit process and LD13 which turns on during a receive process. Refer to the Microchip data sheet for the MCP2200 for more detailed information about the operation of the USB serial converter circuit.

The UDB was designed with the ability to use detachable PIM processor modules. It will work with 16-bit (PIC24 and dsPIC33) PIMs as well as 32-bit (PIC32) PIMs compatible with the Microchip Explorer 16 development board. PIM processor modules are installed onto the pattern of vertical pins at the location labeled PIM Socket on the board. PIMs are visually indexed for proper orientation. The PIM is always installed with the notched corner mark to the upper left. When installing or removing a PIM module, use care to ensure that the pins of the PIM connector socket properly seat into the socket on the PIM and take care to not bend the pins of the PIM socket pattern on the board.

Jumper JP9, labeled PIM Current on the board, can be used to measure the power supply current being consumed by the PIM module. To measure PIM current, remove the shorting block from JP9 and attach an ammeter in series between the two pins of JP9. When using a PIM module and not measuring current consumption of the PIM, ensure that the shorting block is installed on JP9. The PIM will not receive power if the shorting block is not installed.

The jumper at JP2 is used to enable or disable the on-board PIC32MX360 microcontroller. When using a PIM, ensure that the shorting block is removed from JP2. This will cause the on-board PIC32MX360 to be held in reset. If the shorting block is not removed, the signals from the on-board PIC32MX360 will interfere with signals from the processor in the PIM, causing erratic operation, and possibly damaging one or both processors.

The combination of the on-board PIC32MX360 and the ability to use PIM processor allows the UDB to support most 3V, 16-bit and 32-bit PIC and dsPIC® microcontrollers.

When using PIM modules with the UDB board, refer to the Microchip information sheet for the PIM being used for any necessary information about how the microcontroller signals are connected to the PIM Socket pin positions. Many Microchip PIMs are not wired straight through and it is necessary to refer to the Microchip PIM information sheet to understand how they are wired.

The UDB has a PIC32MX360F512L microcontroller soldered onto the board. This microcontroller is wired to the PICtail™ Plus bus in the same manner as would be the case for a PIM plugged into the PIM Socket. This allows the UDB board to be used for PIC32 application development without requiring the use of PIM or DIP socketed microcontrollers.

Jumper JP11, labeled PIC32 Current on the board, can be used to measure the power supply current being consumed by the on-board PIC32 microcontroller. To measure the on-board PIC32 operating current, remove the shorting block from JP11 and insert an ammeter in series between the two pins of JP11. When not measuring power supply current consumption of the on-board PIC32 microcontroller, ensure that the shorting block is installed on JP11. The on-board PIC32 microcontroller will not receive power if the shorting block is not installed on JP11. When not using the on-board PIC32 and using a PIM modules instead, it may still be necessary to have the shorting block installed on JP11. Leaving the on-board PIC32 microcontroller unpowered may load the pins of the PIM down and cause erratic operation of the processor on the PIM module.

Note: The PIC32 Current measurement jumper, JP11, only exists on Revision E and later UDB boards.

The jumper at JP2 is used to enable or disable the on-board PIC32MX360 microcontroller. When using the on-board PIC32 microcontroller, ensure that no PIM is installed on the PIC Socket and insert a shorting block onto JP2. This enables the on-board PIC32 for operation.

WARNING: Most Microchip programming tools, such as the PICkit® 3, are capable of generating the high programming voltages necessary for programming some PIC microcontrollers. This programming voltage can be as high as 13V for some devices. When programming these devices, the programming voltage is applied to the MCLR pin. The MCLR signal from the programming tool will be connected to the MCLR pin of the on-board PIC32 device whenever the shorting block is installed on jumper JP2. If this programming voltage is applied to the board while the shorting block is installed on JP2, the on-board PIC32 device will be destroyed. This situation can occur in unexpected ways. For example, the Microchip MPLAB® or MPLAB® X development environment will automatically cause the programming voltage to be applied when loading a project with a device selected where it is required. Thus, it is possible to destroy the on-board PIC32 device merely by opening a project in the MPLAB® development environment. As a safety precaution, do not leave the shorting block installed on JP2 unless actively using the on-board PIC32 device and only when a project known to be safe has been loaded into the IDE.

The UDB has a PICtail Plus interface that provides the board with basic functionality while still being easily extendable to new technologies as they become available. The PICtail Plus interface is compatible with the PICtail Plus line of expansion modules available from Microchip®.

The PICtail Plus interface is on the right side of the board and labeled PICtail Plus on the board. It is made up of card edge socket, J12, and edge connector land pattern, J13. It is physically and electrically compatible with PICtail Plus expansion modules available from Microchip. Most PICtail modules will plug vertically into socket, J12, but some expansion boards are designed to be coplanar with the microcontroller board and will attach to the card edge land pattern at J13.

The PICtail Plus bus is based on a 120-pin connection divided into three sections of 30pins, 30pins and 56pins. The two 30-pin connections have parallel functionality. Each 30 pin section provides connections to all of the serial communications peripherals, as well as I/O port. This functionality provides enough signals to develop many different expansion interfaces.

In addition to the microcontroller signals, the PICtail Plus bus has pins defined for three power supply voltages and ground. The pins labeled as 3V3 are powered from the main 3.3V power supply on the UDB board. The pins labeled as 5V0 are powered directly from the power supply source selected by the power select jumper J21. These pins will only be at 5.0V if the power supply used to power the board is a regulated 5V supply or USB. The pins labeled as 9V0 are powered from a power supply attached to header J5 in the upper right corner of the board. Header J5 is used to bring in an externally regulated 9V power supply to those pins.

The PICtail Plus connectors are connected to the PIM Socket what is called the PIM bus. There are hard wired connections between the pins of the PIM Socket (and the on-board PIC32 microcontroller) and the pins of the PICtail Plus connectors. It is not necessary to use jumper wires to make connections between PIMs (or the on-board PIC32 microcontroller) and PICtail Plus modules connected to the PICtail connectors. The connections between the PIM connector and the PICtail connectors are the same as on a Microchip® Explorer 16 board.

Access to the signals on the PIM bus can be accomplished using the pin header connectors labeled PIM Headers on the board. These headers: J9, J10, and J11, provide access to all microcontroller signals going between the PIM Socket and the PICtail connectors. Connectors J9 and J10 are 40-pin headers, and J11 is a 16 pin header. These are standard 100mil spaced pin header connectors compatible with MTE style connectors.

These connectors can be used to monitor the signals between the microcontroller and the peripheral for debugging purposes when using a PIM or the on-board PIC32MX360 microcontroller. They can also be used to establish connections to the PICtail Plus signals when using a microcontroller in one of the DIP sockets. In this case, MTE jumper wires would be used to make the connections between the DIP bus and the PIM bus.

Refer to Appendix A: PICtail Plus/PIM Bus Connections for a table showing the correspondences between pin numbers and signal assignments for the PICtail Bus the PIM Bus and the PIM Headers.

The UDB has 3 DIP sockets at locations IC2, IC3, and IC4. These sockets are for 20/14/8-pin 8-Bit PIC, 28-pin PIC24/dsPIC33/PIC32, and 28-pin 8-Bit PIC devices respectively. The board is labeled to reflect this next to each socket. The labeling for IC3 doesn’t mention PIC32, but the board is fully compatible with PIC32MX devices in DIP packages. Generally, only one of these sockets should be used at a time, as all three DIP sockets are wired in parallel and having multiple devices installed simultaneously will cause conflicts between the I/O pins on the various devices.

The pins from the three DIP sockets are wired in parallel and make up the DIP bus. This bus is wired to the DIP Bus header, and jumper wires can be used to jumper signals from the DIP bus header to other locations on the board, such as the user I/O buttons/LEDs or to off board devices.

Although the IC2 socket is a 20-pin socket, smaller pin count DIP devices may be used. When installing a smaller pin count device, such as an 8-pin DIP device into the 20-pin DIP socket, load the device such that pin 1 on the microcontroller is inserted into pin 1 on the socket, i.e. the devices are loaded at the upper end of the socket. The determination of which PIC devices are compatible with the UDB board, and which socket to use is based on the operating voltage range of the microcontroller and the layout of the power, ground and MCLR pins on the device. The UDB operates the microcontroller at 3.3V and therefore, only devices that operate at 3.3V may be used. Microchip® has several conventions for the placement of the power, ground and MCLR pins on their microcontrollers. The following describes the way that the sockets are configured:

The socket at IC2 is designed to accommodate PIC12/PIC16 devices of up to 20 pins. On this socket, VDD is on pin 1, VSS is on pin 20, and MCLR is on pin 4. Any PIC device that matches this pin assignment will be usable. Note that for smaller pin count devices, VSS will be on the highest numbered pin, e.g. pin 8 on an 8-pin device. The following are some of the devices usable in this socket: PIC12F609, PIC12F615, PIC12F617, PIC12F1822, PIC12F1823, PIC16F631, PIC16F677, PIC16F685, PIC16F687, PIC16F689, PIC16F690.

The socket at IC4 is designed to accommodate 28-pin PIC16/PIC18 devices. This socket is wired with MCLR on pin 1, VSS on pins 8 and 19, and VDD on pin 20. The following are some of the devices usable in this socket: PIC16F882, PIC16F883, PIC16F886, PIC16F1933, PIC16F1936, PIC16F1938, PIC18F24J10, PIC18F25J10, PIC18F23K20, PIC18F24K20, PIC18F25K20, PIC18F26K20.

The PIC24J10 and PIC25J10 microcontroller families have an internal voltage regulator for the core operating voltage that requires an external bypass capacitor. For these devices, a 10uF capacitor must be connected to pin-6 on the microcontroller. The UDB board provides this capacitor and jumper JP6 is used to place it in or out of circuit. When using a microcontroller in this family (or possibly others that have this same requirement), install a shorting block onto JP6. These microcontrollers will operate erratically or not at all if this jumper is not installed. When using other microcontroller families, the shorting block on JP6 should be removed. If this shorting block is not removed, the 10uF capacitor will load down the I/O pin significantly slowing down its operation, and possibly stressing the output driver due to excessive current flow when the pin is switching.

The socket at IC3 is designed to accommodate PIC24, dsPIC33 and PIC32 devices in 28-pin DIP packages. The following are examples of PIC devices usable in this socket: PIC24FJxxxGA002 family, PIC24FJxxxGA102 family, PIC24FJxxxGB004 family, dsPIC33FJxxxMC202 family, dsPIC33FJxxxMC302 family, dsPIC33FJxxxMC802 family, dsPIC33FJxxxGP202 family, dsPIC33FJxxxGP302 family, dsPICFJxxxGP802 family, dsPIC33FJ06GS102, dsPICFJ06GS202, dsPICFJ16GS402, dsPICFJ16GS502, any PIC32MX1xx or PIC32MX2xx device.

Various jumpers must be set appropriately to configure the device programming signals depending on which DIP socket is being used. Refer to section 6.3 below for information describing the jumper settings required.

The various PIC microcontrollers that can be used in the DIP sockets all have multiple options for the clock source for the main processor clock. In many cases, an internal oscillator can be used and it is not necessary to set any jumpers when using the internal oscillator. The UDB board provides an external oscillator that can be selected as a clock source when an external oscillator is desired. No explicit provision is made for use of an external crystal or resonator to make use of that clock option.

The UDB board provides an 8-pin DIP socket for an external oscillator. Refer to section 9 below for more information about this oscillator.

Jumper JP7 is used to select the external clock source for the DIP socket being used. JP7 is located near the 20/14/8-pin DIP socket IC2 and the DIP bus header. Place the shorting block in the IC2 position to use the external clock source with DIP socket IC2, or in the IC3/IC4 position to use the external clock source with either of those sockets. Remove the shorting block from JP7 when using the internal oscillator option with the DIP device.

The three DIP sockets are connected in parallel and wired to the DIP bus header connector, J6. Connector J6 is used to access the I/O signals for the microcontroller being used in one of the DIP sockets. Jumper wires can be used to connect DIP microcontroller signals from the DIP bus connector either to on-board I/O via connector J3; to PIM bus locations via connectors J9, J10, or J11, allowing access to the PICtail™ connectors and thus PICtail™ Plus modules; or to off-board devices.

The assignment of DIP socket pins to header pins on the DIP bus connector follows the convention for pin numbering on DIP sockets, i.e. pin 1 is on the upper left corner to the header and the pin numbering proceeds counter-clockwise around the pins of the header. Connector J6 is a 28-pin (2×14) header connector. It is wired straight through for the 28-pin DIP sockets. When using the 20/14/8-pin DIP socket, or smaller DIP packages (e.g. 8-pin, 14-pin, etc.) in any of the sockets, take care to identify the correct pins to find the microcontroller signals on the DIP bus connector.

To aid in identifying which pins will be active when using smaller pin count DIP devices, vertical bars are marked on silk screen of the board to identify the pins in use for each package size. Refer to the following tables for the correspondence between DIP package pins and connector pins on the DIP bus connector.