Hardware Description
11
SPRUII7 – June 2018
Copyright © 2018, Texas Instruments Incorporated
C2000™ Piccolo™ F28004x Series LaunchPad™ Development Kit
2.3
Alternate Routing
2.3.1
Overview
The F280049C MCU is a very versatile device in a small package. To balance compatibility with
BoosterPack standards as well as showcasing the versatility of the F280049C, some complexity was
added to the design. Most features aligning with the BoosterPack standard are available by default. The
additional functions are selected using a switches, or static resistors which can be added or removed. This
section covers the alternate functions and how to enable them. Note that by enabling certain alternate
features, standard BoosterPack functionality may be lost. The switches are configured such that it is not
possible to connect multiple functions to the same header.
is a master list of all of the possible functions controlled by the alternate routing switches:
Table 4. Alternate Function Switch Settings
Pins
S3.1
S3.2
S4
S6
S8
S9
Function
Note
GPIO28/GPIO29
x
x
x
0
0
x
SCIA to virtual COM port
Default configuration
x
x
x
1
x
x
SCIA to BoosterPack Site 2
GPIO35/GPIO37
1
x
1
x
1
x
SCIA to virtual COM port
1
x
0
x
x
x
I2C on BoosterPack Site 1
Default configuration
0
x
1
x
x
x
QEP1 on J12
GPIO59
0
x
x
x
x
x
QEP1 on J12
1
x
x
x
x
x
GPIO on BoosterPack Site 1
Default configuration
GPIO14/GPIO15/
GPIO26
x
0
x
x
x
x
QEP2 on J13
x
1
x
x
x
x
GPIO on BoosterPack Site 2
Default configuration
GPIO32/GPIO33
x
x
x
x
x
0
CAN on J14
x
x
x
x
x
1
GPIO on BoosterPack Site 2
Default configuration
(1) Cells marked with 'x' indicate that the state of that switch has no impact on the function of that particular signal.
(2) GPIO33 is also connected to the FSIRXCLK pin on J11 through a 0
Ω
resistor R46. If CAN functionality is required, ensure that
R46 is populated.
2.3.2
UART
This LaunchPad allows for one of two sets of pins to be used for the SCIA UART routed to the virtual
COM port of the XDS110. By default, GPIO28 and GPIO29 are routed to the virtual COM port and not
available on the BoosterPack connector. Alternately, GPIO35 and GPIO37 can be routed to the virtual
COM port.
When UART functionality is not needed at the virtual COM port, the GPIOs can be routed to the
BoosterPack connectors for BoosterPack standard functions.
2.3.3
eQEP
The LaunchPad has the ability to connect to two independent linear or rotary encoders through the
F28004x on-chip eQEP interfaces: Header J12 is connected to eQEP1 and header J13 is connected to
eQEP2. By default, this connection is not active and the GPIOs are routed to the BoosterPack connectors.
The eQEP signals are routed through TI SN74LV4053A Triple 2-Channel Analog
Multiplexer/Demultiplexer ICs (U8/U9) to select the functions. Once the eQEP signals have been selected
through U8/U9, the 3.3 V signals are stepped up through a TI TXB0106PWR Level Translator (U7) to 5 V
at the connectors.
2.3.3.1
EQEP1
GPIO35, GPIO37, and GPIO59 are routed to J12 through U9. By setting position 1 of S3 to 0, the eQEP
signals are routed to J12. GPIO35 and GPIO37 also require that S4 is set to 1. In addition to configuring
the switches, ensure that the EQEP1 function is selected in the GPIO Mux.
