Datasheet

Development Board Hardware
 2010 Microchip Technology Inc. DS51911A-page 35
Due to pin constraints, some features of the development board overlap more than oth-
ers. In these cases, configuring the board for one major functionality means limiting or
disabling another. Table 4-2 shows the major areas of overlap. Additional details are
provided in the following sections.
4.4.1 User-Defined Inputs and LEDs
The PIC24FJ256DA210 Development Board implements a variety of user-defined
inputs: push button switches, capacitance-sensing touch pads, a potentiometer, and
four LEDs. The development board multiplexes the switches, touch sensors, potenti-
ometer and three of the LEDs through three I/O pins (RB5, RE9 and RG8). For each of
these pins, only one input mode can be chosen at any given time. The fourth LED (D4)
shares a pin with an address line for the external memory devices.
Note that the implementation of shared inputs and outputs used in the development
board is not a recommended design practice. In this case, it is implemented in consid-
eration of I/O pin constraints. Using separate pins for different input and output features
is always recommended.
If the CTMU touch sensors are enabled, the LEDs can be used simultaneously. How-
ever, care must be taken in the application to switch the I/O pins alternately as analog
input and digital output as required. Please refer to the “PIC24FJ256DA210 Family
Data Sheet” (DS39969) for details on configuring the I/O ports.
The user-defined features are configured using jumpers J13, J14 and J15. In some
cases, modifications to accompanying resistors are also required. The locations of the
components are shown in Figure 4-3. A summary of the jumper settings is provided in
Table 4- 3.
TABLE 4-2: SUMMARY OF BOARD CONFIGURATIONS VS. AVAILABILITY
OF SPECIFIC FEATURES
Individual Feature
Board Configuration Options
No CTMU CTMU USB OTG PICtail™ Plus Options
Flash and SRAM
access modes
Byte and
Word
Byte and
Word
Byte and
Word
Word only
(1)
Parallel Flash/
SPI Flash Memory
512 Kbytes/
2 Mbit
512 Kbytes/
2 Mbit
512 Kbytes/
2 Mbit
256 Kbytes/N.A.
SRAM 512 Kbytes 512 Kbytes 512 Kbytes 256 Kbytes
Resistive Touchscreen
OR Touch SPI channel
YYY Y
Potentiometer Y N N Y
Touch pads (CTMU) N Y
(2)
NN
User-defined Buttons Y N N Y
(2)
User-defined LEDs N Y
(3)
N1
UART Channels 1 1 1 1
USB Modes Host or
Device
Host or
Device
OTG only Host or Device
PICtail Plus Expansion N Y
(3)
NY
Note 1: The only display mode available in this configuration is 16 bpp.
2: CTMU channels and push buttons are available with certain PICtail™ Daughter
Boards only. The number of inputs available depends on the daughter board and
the application. See Section 4.4.6 “PICtail™ Plus Card Modular Expansion
Connector” for additional information.
3: LED outputs are shared with CTMU input channels.