CS48AU2B Data Sheet

Dedicated 32-bit Audio DSP for Audyssey Laboratories Technology

DS876F3

Copyright 2009 Cirrus Logic

9

CONFIDENTIAL

(that is, host MCU present) a GPIO will be used to signal the host that the watchdog has expired and

the DSP should be rebooted and re-configured.

4.3 DSP I/O Description

4.3.1 Multiplexed Pins

Many of the CS48AU2B pins are multi-functional. For details on pin functionality please refer to the

CS485xx Hardware User’s Manual.

4.3.2 Termination Requirements

Open-drain pins on the CS48AU2B must be pulled high for proper operation. Please refer to the

CS485xx Hardware User’s Manual to identify which pins are open-drain and what value of pull-up

resistor is required for proper operation.

Mode select pins in the CS48AU2B are used to select the boot mode upon the rising edge from

reset. A detailed explanation of termination requirements for each communication mode select pin

can be found in the CS485xx Hardware User’s Manual.

4.3.3 Pads

The CS48AU2B I/Os operate from the 3.3 V supply and are 5 V tolerant.

4.4 Application Code Security

The external program code may be encrypted by the programmer to protect any intellectual property

it may contain. A secret, customer-specific key is used to encrypt the program code that is to be

stored external to the device. Please contact your local Cirrus representative for details.