Digital/Analogue Two-Way Radio Products

The SCT3288 is a low power high performance baseband processor supporting dPMR and DMR protocol. With an internal codec (audio band ADC and DAC), it completes the entire physical layer and data link layer, and most of the call control layer processing of dPMR and DMR protocols. In dPMR mode, SCT3288 complies with ETSI TS 102 490 and ETSI TS 102 658. In DMR mode, it complies with ETSI TS 102 361. The two front page diagrams show the SCT3288 used in a dPMR or DMR system with conventional RF circuits, and used with the CMX994E (SCT3811) direct-conversion receiver. The SCT3288 is designed for easy migration from analog radios. The system designer can start with a typical analog radio, replacing the analog baseband processor with the SCT3288, to obtain the simplest form of a dPMR or DMR radio. To achieve the full potential of dPMR or DMR, application-level software programming is required on the host processor.

The SCT3288 contains an I2S interface, a slave SPI interface, a master SPI interface with two chip selectors, an I2C interface and 8 programmable I/O ports. The I2S is used for connection with an external codec or a receiver with digital I/Q interface. The master SPI can be used to control the RF PLL such as the CMX940 or a transceiver such as CMX994E (SCT3811).

The SCT3288 communicates with a host processor through the slave SPI interface. The firmware of the SCT3288 is stored on chip. The SCT3288 gives a response to the host processor to indicate that it has started up successfully and is ready to accept commands from the host processor. Following a correct command from the host the SCT3288 will then load and execute the entire firmware.

The SCT3288 core logic operates at 1.2 V, and the I/O operates at 1.8-3.6V. The SCT3288 is supplied in a QFN88 10x10mm2 and 0.4mm pitch, ideal for small form factor designs.

The CMX994E and the SCT3811 are equivalent products. Only the CMX994E is available through CML Micro.