Specifications

18 DSP56800 Hardware Interface Techniques 
Peripheral Interfaces
4. Peripheral Interfaces
The following sections provide example interfaces to DSP56800 peripherals. The interfaces have been
implemented and tested on Evaluation Module (EVM) hardware using various members of the
DSP56800 family.
4.1 GPIO Interface Example
An example interface making use of the DSP56800 GPIO pins is given below. The GPIO pins are
controllable via SDK driver routines. Refer to the SDK Programmer’s Guide for details.
Two general-purpose user pushbutton switches are connected to Port D GPIO signals GPIOB0 and
GPIOB1. A Run/Stop toggle switch is connected to GPIO signal GPIOB2; see Figure 16.
Figure 16. Run/Stop and General Purpose Switches
4.2 CAN Interface (DSP56F805)
The DSP56F805EVM board contains a CAN physical-layer interface chip that is attached to the
MSCAN_RX and MSCAN_TX pins on the DSP56F805. The EVM board uses a Philips, PCA82C250,
high speed, 1Mbps, physical layer interface chip. Due to the +5.0V operating voltage of the CAN chip,
a pull-up to +5.0V is required to level shift the Transmit Data output line from the DSP56F805. A
primary, J1, and a daisy-chain, J2, CAN connector are provided to allow easy daisy-chaining of CAN
devices. CAN bus termination of 120 ohms can be provided by adding a jumper as shown. Refer to
Figure 4 for the CAN connector signals and Figure 17 for a connection diagram.
DSP56F807
+3.3V
GPIOB0
+3.3V
10K
10K
10K
GP #1 SWITCH
GP #2 SWITCH
START/STOP SWITCH
+3.3V
GPIOB1
GPIOB2
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cale Semiconductor,
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