DSP56156 View Datasheet(PDF) - Motorola => Freescale

Part Name

Description

Manufacturer

DSP56156

16-bit Digital Signal Processor

Motorola => Freescale 

Freescale Semiconductor, Inc.

Pin Descriptions

OnCE

On-Chip Codec

On-Chip Emulation

(OnCETM Port)

DSI/OS0 (Debug Serial Input/Chip Status 0) —

bidirectional. The DSI/OS0 pin, when

an input, is the pin through which seri-

al data or commands are provided to

the OnCE port controller. The data re-

ceived on the DSI pin will be recog-

nized only when the DSP has entered

the debug mode of operation. Data

must have valid TTL logic levels before

the serial clock falling edge. Data is al-

ways shifted into the OnCE serial port

most significant bit (MSB) first. When the

DSP is not in the debug mode, the DSI/

OS0 pin provides information about the

chip status if it is an output and used in

conjunction with the OS1 pin.

DSCK/OS1 (Debug Serial Clock/Chip Status 1)

— bidirectional. The DSCK/OS1 pin,

when an input, is the pin through

which the serial clock is supplied to the

OnCE port. The serial clock provides

pulses required to shift data into and

out of the OnCE serial port. Data is

clocked into the OnCE port on the fall-

ing edge and is clocked out of the

OnCE serial port on the rising edge. If

the DSCK/OS1 pin is an output and

used in conjunction with the OS0 pin, it

provides information about the chip

status when the DSP is not in the debug

mode.

DSO (Debug Serial) — output. The debug

serial output provides the data con-

tained in one of the OnCE port control-

ler registers as specified by the last

command received from the command

controller. When idle, this pin is high.

When the requested data is available, the

DSO line will be asserted (negative true

logic) for four T cycles (one instruction

cycle) to indicate that the serial shift reg-

ister is ready to receive clocks in order to

deliver the data. When the chip enters

the debug mode due to an external de-

bug request (DR), an internal software

debug request (DEBUG), a hardware

breakpoint occurrence or a trace/step

occurrence, this line will be asserted for

three T cycles to indicate that the chip

has entered the debug mode and is wait-

ing for commands. Data is always shift-

ed out the OnCE serial port with the

most significant bit first.

DR (Debug Request) — input. The debug

request input provides a means of en-

tering the debug mode of operation.

This pin, when asserted, will cause the

DSP to finish the current instruction be-

ing executed, enter the debug mode,

and wait for commands to be entered

from the debug serial input line.

On-Chip Codec

AUX (Auxiliary) — input. This pin is select-

ed as the analog input to the A/D con-

verter when the INS bit is set in the

codec control register COCR. This pin

should be left floating when the codec

is not used.

BIAS (Bias current) — input. This input is

used to determine the bias current for

the analog circuitry. Connecting a re-

sistor between BIAS and GNDA will

program the current bias generator.

This pin should be left floating when

the codec is not used.

MIC (Microphone) — input. This pin is se-

lected as the analog input to the A/D

converter when the INS bit is cleared in

MOTOROLA

DSP56156 Data Sheet

13

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