DSP56854 View Datasheet(PDF) - Freescale Semiconductor

Part Name

Description

Manufacturer

DSP56854

16-bit Digital Signal Controllers

Freescale Semiconductor 

Introduction

Table 3-1. 56854 Signal and Package Information for the 128-pin LQFP (Continued)

Pin No.

Signal Name

Type

Description

4

SS

Input

SPI Slave Select (SS)—This input pin selects a slave device before

a master device can exchange data with the slave device. SS must

be low before data transactions and must stay low for the duration

of the transaction. The SS line of the master must be held high.

GPIOF3

Input/Output

Port F GPIO (3)—This pin is a General Purpose I/O (GPIO) pin that

can individually be programmed as input or output pin.

24

XTAL

Input/Output Crystal Oscillator Output (XTAL)—This output connects the

internal crystal oscillator output to an external crystal. If an external

clock source other than a crystal oscillator is used, XTAL must be

used as the input.

25

EXTAL

Input

External Crystal Oscillator Input (EXTAL)—This input should be

connected to an external crystal. If an external clock source other

than a crystal oscillator is used, EXTAL must be tied off. See

Section 4.5.2

33

CLKO

Output

Clock Output (CLKO)—This pin outputs a buffered clock signal.

When enabled, this signal is the system clock divided by four.

54

TCK

Input

Test Clock Input (TCK)—This input pin provides a gated clock to

synchronize the test logic and to shift serial data to the

JTAG/Enhanced OnCE port. The pin is connected internally to a

pull-down resistor.

52

TDI

Input

Test Data Input (TDI)—This input pin provides a serial input data

stream to the JTAG/Enhanced OnCE port. It is sampled on the

rising edge of TCK and has an on-chip pull-up resistor.

51

TDO

Output (Z)

Test Data Output (TDO)—This tri-statable output pin provides a

serial output data stream from the JTAG/Enhanced OnCE port. It is

driven in the Shift-IR and Shift-DR controller states, and changes on

the falling edge of TCK.

53

TMS

Input

Test Mode Select Input (TMS)—This input pin is used to sequence

the JTAG TAP controller’s state machine. It is sampled on the rising

edge of TCK and has an on-chip pull-up resistor.

Note: Always tie the TMS pin to VDD through a 2.2K resistor.

56854 Technical Data, Rev. 6

Freescale Semiconductor

21

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