Accelerators Reduce DSC Overhead in Motion Control Applications

Accelerators Reduce DSC Overhead in Motion Control Applications

Texas Instrument's (TI) 120 MHz C2000 Piccolo F2807x (Fig. 1) digital signal controller (DSC) incorporates a range of features to offload processing chores. This includes a trigonometric math unit (TMU) and control law accelerator (CLA). The controller is available with 512 Kbytes of ECC flash memory, 100 Kbytes of SRAM with parity support, a boot ROM and a 16-/32-bit external memory interface (EMIF). It also has a pair of 128-bit security zones.

Figure 1. The C2000 Piccolo F2807x includes a trigonometric math unit (TMU) and control law accelerator (CLA) to handle data from a trio of 3.1 Msample/s, 12-bit ADCs and other on-chip peripherals.

The TMU implements sin, cos, atan, divide, and square root instructions. This can provide a 5x to 10x performance increase compared to software algorithms. The TMU can give the C2000 an edge over the competition that lack this type of acceleration.

The CLA can handle complex motion control algorithms independent of the main CPU. It can implement deterministic algorithms and significantly reduce the CPU overhead for these control tasks allowing the CPU to address other aspects of an application such as communication and analysis.

The chip's analog support is impressive. IT has a trio of 12-bit ADCs that can deliver up to 3.1 Msamples/s. It has eight windowed compartors with an integrated DAC to handle over/under voltage and current fault detection. There is also a set of eight sigma delta channels with a pair of filters per channel. There is an on-chip temperature sensor reducing overall system bill of materials (BOM). The chip has a trio of 12-bit DACs.

To assist with motor control chores, the chip includes three eQEP (enhanced quadrature encoder pulse) modules and six eCAP (enhanced capture) timer modules. There are a dozen enhanced PWMs.

The chip has a range of connectivity peripherals including four UARTs, a pair of I2C ports, three SPI ports and two McBSP ports. The USB 2.0 OTG support includes a built-in PHY. The F2807x also has two CAN 2.0B ports.

Development hardware includes the C2000 Piccolo F2807x controlCARD (Fig. 2). This plugs into the TMS320F2807x Experimenter’s Kit prototyping board. It can also plug into other controlCARD compatible development platforms.

Figure 2. The C2000 Piccolo F2807x controlCARD provides a convenient development platform.

The F2807x is supported by TI's ControlSUITE software. This includes device and application libraries as well as examples to handle a range of motor control applications. ControlSUITE works with TI's Code Composer Studio (CCS) integrated development environment v6. CCS is based on the open-source Eclipse development platform. The chip is supported by a range of third party tools from companies such as Altair and The Mathworks.

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