System description

STA1074, STA1078, STA1079, STA1088

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DocID028356 Rev 1

2.5.1

Routing and sample rate converters

Each audio interface can be routed in both directions (IN/OUT) through sample rate

converters, which allow normalizing the sampling rate to the sound processing engine. The

audio routing infrastructure is designed to deliver high quality sample rate conversion on

multiple channels, allowing simultaneous audio streams, such as Bluetooth Hands Free, to

be handled without CPU load.

In order to generate multiple sampling rate audio frequencies, a dedicated fractional PLL is

also provided. This PLL also allows an efficient implementation of cellular modem playback,

by dynamically adjusting the reconstructed audio sampling rate without CPU overload.

2.5.2

DSP Subsystem

Some devices in Telemaco2 family are equipped with an embedded DSP subsystem

dedicated to sound processing and other signal processing intensive tasks, like echo/noise

cancellation, sound effects generation. DSP subsystem is integrated with the sound

subsystem with a specific isochronous bus.

Each DSP is connected to other DSPs and audio peripherals by means of an isochronous

bus infrastructure which guarantees a controlled throughput and latency for all audio

transfers.

2.6

Secure CAN subsystem

Telemaco2 family devices allow isolating critical code from main application by

implementing a dedicated subsystem based on ARM Cortex-M3, along with:



Dedicated embedded SRAM



CAN controller



Dedicated GPIOs

In order to guarantee security of CAN network, all of the above can be completely isolated

from the rest of the system, in such a way that no application running on CorteX-R4 can

access by any mean to CAN specific re-sources. This subsystem can also be dedicated to

implement secure features, such as boot authentication, as well as interrupt intensive tasks

to offload main CPU. The secure subsystem communicates with the application running on

CortexR4 using a Hardware Mailbox interrupt based mechanism.