TWR-K40X256 Freescale Semiconductor, TWR-K40X256 Datasheet - Page 15

• Manufacturer Part Number: TWR-K40X256
• Description: TOWER SYSTEM BOARD K40X256
• Manufacturer: Freescale Semiconductor
• Series: Kinetisr
• Type: MCUr

Specifications of TWR-K40X256

• Contents: Board
• Processor To Be Evaluated: K40
• Data Bus Width: 32 bit
• Interface Type: USB, CAN, I2C, SPI, UART
• Dimensions: 3.5 in x 3.2 in
• Operating Supply Voltage: 1.71 V to 3.6 V
• Silicon Manufacturer: Freescale
• Core Architecture: ARM
• Core Sub-architecture: Cortex - M4
• Silicon Core Number: MK
• Silicon Family Name: Kinetis - K40
• Kit Contents: Board Only
• Rohs Compliant: Yes
• For Use With/related Products: Freescale Tower System, K40X256
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2.13 External Bus Interface – FlexBus
The K40 device features a multi-function external bus interface called the FlexBus interface controller
capable of interfacing to slave-only devices. The FlexBus interface is not used directly on the TWR-
K40X256. Instead, a subset of the FlexBus is connected to the Primary Connector so that the external
bus can access devices on Tower peripheral modules.
The Primary Connector supports up to 20 address lines, 8 data lines, 2 chip-selects, read/write, and
output enable signals. The SDHC signals of the K40 are multiplexed over the upper FlexBus address
signals (FB_AD[27:23]), so a multiplexed mode of operation is used on the TWR-K40X256. An address
latch is provided to de-multiplex the address and data signals prior to connecting them to the Primary
Connector. Refer to sheet 8 of the TWR-K40X256 schematics for more details.
Note: The K40 Flexbus implementation provides an option for byte lane alignment. On the TWR-
K40X256, FB_AD[7:0] are used for the data byte. Therefore, for proper operation software must set the
CSCRx[BLS] bit to shift the data bus to the right byte lane. Refer to the FlexBus chapter in the K40
Family Reference Manual for more information.
3 Jumper Table
There are several jumpers on the TWR-K40X256 that provide configuration selection and signal
isolation. Refer to the following table for details. The default installed jumper settings are shown in
bold with asterisks.
Jumper
J11
J3
J5
J6
Figure 8. Flexbus Connections for External Memory Port Sizes (CSCRn[BLS] = 1)
USB VREGIN Power
Connection
Flexbus Address Latch
Selection
Infrared Transmitter
Connection
MCU Power Connection
Option
TWR-K40X256 Tower Module User's Manual
Table 5. TWR-K40X256 Jumper Table
Setting
*OFF*
*ON*
*2-3*
*ON*
OFF
1-2
ON
Connect USB0_VBUS from Primary Elevator (A57) to VREGIN
Disconnect VREGIN from Primary Elevator
Flexbus address latch disabled
Flexbus address latch enabled
Connect PTD7/CMT_IRO/UART0_TX to IR Transmitter (D3)
Disconnect PTD7/CMT_IRO/UART0_TX from IR Transmitter (D3)
Connect on-board 3.3V supply to MCU
Description
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