STA2064

System description

Doc ID 16057 Rev 1

9/19

2.6.7

AC97 controller

AC97 audio controller enables SOC to control external AC97 CODECs using SOC AMBA

interconnect. It is implemented in a way to minimize audio data handling by SOC processor

with dedicated audio DMA engine. AC97 Audio Controller supports AC97 revision 2.3

compliant audio CODECs. External interface supports one external AC97 CODEC with 6

output (3 of them can be Double Rate Audio) and 3 input channels.

2.6.8

CAN

STA2064 features one CAN module that is compliant with the CAN specification V2.0 part B

(active). The bit rate can be programmed up to 1 MBaud.

2.7

Specific functions

2.7.1

GPS

STA2064 integrates HPGPS_G2, ST’s proprietary GPS IP, which is ST’s 2nd generation

High-Sensitivity Baseband. The Baseband is fully compliant with GPS and Galileo L1/E1

signal specifications, and is optimised to maximise sensitivity for both acquisition and

tracking in difficult environments. Please refer to GPS solution specifications and software

release notes for more specific performance details.

The baseband accepts a 3-bit signal at a 4MHz IF from its companion RF chip, the

STA5630. It downconverts this to baseband and feeds it to the acquisition engines (for up to

8 satellites simultaneously) and the tracking channels (for up to 32 satellites

simultaneously).

The highly parallel correlators in the acquisition engines identify each satellite signal in time

and frequency domains, and the results are passed to the tracking channels. The tracking

channels fine-tune the lock, then track continuously, providing orbit data and timing

measurements to the ARM CPUs.

The management of the hardware for these operations, and the myriad of complex

conditions that arise, is performed in a complete GPS software library supplied by ST. This

library also takes the resultant measurement data and processes it to maintain satellite

databases and calculate the user's position, velocity and time(PVT) solutions.

The PVT solution, and other useful data, is made available to the user's application via an

API in the ST GPS library. This runs on a royalty-free real-time kernel (OS20), with ports to

industry-standard operating systems also available. In stand-alone mode, the outputs are

generated in standard NMEA message format.

Options are also available in the software library to support ST Self-Trained Assisted GPS

(ST-AGPS), a complete and scalable solution for assisting GPS start-up with Autonomous

Ephemeris prediction when no network is available, and with simple download when a

network is available followed by prediction for the following 7 days.

The GPS subsystem is based on an ARM966 processor and is clocked by two clocks:

●

MCLK:

ARM966 CPU clock

●

MCLK is derived from the PLL2 clock with a divisor from 3 to 16, giving an ARM966

operating frequency in the range from 208 to 39 MHz, in the case the PLL2 is running at 624