Analog Devices ADSP-SC58 Series Hardware Reference Manual page 1138

23 General-Purpose Counter (CNT)
The GP counter converts pulses from incremental position encoders into data that is representative of the actual
position of the pulse. This conversion is done by integrating (counting) pulses on one or two inputs. Since integra-
tion provides relative position, some devices also feature a zero-position input (zero marker). The GP counter can
use the zero position input feature to establish a reference point for verifying that the acquired position does not
drift over time. In addition, the GP counter can use the incremental position information to determine speed, if the
time intervals are measured.
The GP counter provides flexible ways to establish position information. When used with the GP timer block, the
GP counter can allow for the acquisition of coherent position or time stamp information that enables speed calcula-
tion.
GP Counter Features
The GP counter includes the following features:
• 32-bit up or down counter
• Quadrature encode mode (Gray code)
• Binary encoder mode
• Alternative frequency-direction mode
• Timed direction and up or down counting modes
• Zero marker or push-button support
• Capture event timing in association with GP Timer
• Boundary comparison and boundary setting features
• M/N frequency scaling of the inputs CUD/CDG
ADSP-SC58x/ADSP-2158x SHARC+ Processor Hardware Reference
General-Purpose Counter (CNT)
23–1