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User Module Datasheet: DTMF Dialer Analog Output Datasheet DTMFDialer V 1.5 (CY8C29/27/24/xxx, CY8C23x33, CY8CLED04/08/16, CY8CLED0xD, CY8CLED0xG, CY8C28x45, CY8CPLC20, CY8CLED16P01, CY8C28x43, CY8C28x52) | Cypress Semiconductor

User Module Datasheet: DTMF Dialer Analog Output Datasheet DTMFDialer V 1.5 (CY8C29/27/24/xxx, CY8C23x33, CY8CLED04/08/16, CY8CLED0xD, CY8CLED0xG, CY8C28x45, CY8CPLC20, CY8CLED16P01, CY8C28x43, CY8C28x52)

Last Updated: 
May 27, 2014
Version: 
1.5

Features and Overview

  • Flexible clocking options
  • Analog output
  • Runs in background to allow system control while dialing (configuration option)
  • Runs in foreground to minimize use of RAM (configuration option)
  • Tones can be output continuously under program control
  • Automatically adds configured tone spacing to all output tones
  • Tone duration can be configured
  • Output capable of -1.7 dBm un-amplified into 600 ohm load, and up to +3.1 dBm amplified drive
  • Output driver capable of driving 32 ohm load at 5 Vrms


The DTMFDialer User Module is a Dual Tone Multiple Frequency signal generator. It provides a 6-bit, 2.6 volt full-scale analog output, centered around AGND. The output is a pair of simultaneously generated table sinusoids (tones) that are updated at a user-selectable update frequency. Selection of the update frequency causes a trade-off between CPU loading and signal distortion. Output tone generation is done in an interrupt routine to minimize sample skew and related distortion. Configuration options provide the ability to make design trade-off between RAM consumption and other operational features.