954957502EE156| Application Note
a Engineer To Engineer Note EE-156
Technical Notes on using Analog Devices' DSP components and development tools
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Support for the H.100 protocol on the ADSP-2191
DSP Applications Group, March 2002 - Rev 0.1
The reverse happens for the receive direction. Data is accepted on the SPORT's DR pin, and serially transmitted to the Receive Shift register. After a word is received and optional decompanding, the data is transferred to the Receive Data register. By writing to different control registers, the serial clock frequency, data format and length, multi-channel mode select, and other parameters can be programmed on the SPORTs. Direct Memory Access (DMA) is also supported on each SPORT. The transmit channel enables DMA transfers from memory to SPORT, while the receive channel enables DMA transfers from SPORT to memory.
The serial ports of the ADSP-2191 provide support for the H.100 standard protocol. It is also the International Telecommunication Union's recommendation for visual telephone systems. This application note describes the configurations necessary to be compatible with the H.100 standard protocol. The hardware used to test the support for this protocol was the ADSP-2191 EZ-KIT Lite. The software used was VisualDSP++ 2.0 with SP1. The example code is included at the end of this application note.
Hardware Connections On the ADSP-2191 EZ-KIT Lite, the SPORT0 and SPORT1 pins are brought out via the P6 and P7 SPORT connectors, respectively. Using SPORT1 in this application, the DT1 and DR1 pins are connected together to create a loopback of the data transmitted and received. Because H.100 applications always runs in multi-channel mode, the TCLK1 and RCLK1 pins must be wired together. In multi-channel mode, the TCLK pin is always an input. In this application, RCLK1 is generated internally.
Introduction The ADSP-2191 has three independent, synchronous serial ports (SPORT0, SPORT1, and SPORT2). Each one of the serial ports supports H.100. In this example, SPORT1 is used. On each SPORT, data can be simultaneously transferred in both transmit and receive directions. For each SPORT, data is transmitted from the IO bus to the Transmit Data register. After optional companding, data is transferred to the Transmit Shift register. Here the bits are shifted out serially on the SPORT's DT pin.
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