CP2103 USB to TTL Converter

The CM8870PI provides full DTMF receiver capability by integrating both the bandsplit filter and digital decoder functions into a single 18-pin DIP. The filter section uses a switched capacitor technique for both high and low group filters and dial tone rejection. The CM8870 decoder uses digital counting techniques for the detection and decoding of all 16 DTMF tone pairs into a 4-bit code. This DTMF receiver minimizes external component count by providing an on-chip differential input ampli-fier, clock generator, and a latched three state interface bus. The on-chip clock generator requires only a low cost TV crystal or ceramic resonator as an external component.

Features of FT232

• Single chip USB to asynchronous serial data transfer interface.

• Entire USB protocol handled on the chip. No USB specific firmware programming required.

• Fully integrated 1024 bit EEPROM storing device descriptors and CBUS I/O configuration.

• Fully integrated USB termination resistors.

• Fully integrated clock generation with no external crystal required plus optional clock output selection enabling a glue-less interface to external MCU or FPGA.

• Data transfer rates from 300 baud to 3 Mbaud (RS422, RS485, RS232) at TTL levels.

• 128 byte receive buffer and 256 byte transmit buffer utilising buffer smoothing technology to allow for high data throughput.

The MT8870D/MT8870D-1 is a complete DTMF receiver integrating both the band split filter and digital decoder functions. The filter section uses switched capacitor techniques for high and low group filters; the decoder uses digital counting techniques to detect and decode all 16 DTMF tone pairs into a 4-bit code. External component count is minimized by on chip provision of a differential input amplifier, clock oscillator and latched three-state bus interface.