MSM6789

¡ Semiconductor ¡ Semiconductor MSM6789A/6789L GENERAL DESCRIPTION MSM6789A/6789L SBC Solid-State Recorder IC The MSM6789A/6789L, an improved version of MSM6788, is a solid-state recorder developed using the Sub Band Coding (SBC) method. Just like MSM6788, the MSM6789A/6789L has a stand-alone mode and a microcontroller interface mode. In the stand-alone mode, record/playback conditions can be selected from pins and the MSM6789A/6789L can be controlled by a simple drive timing. In the microcontroller interface mode, record/playback can be controlled by commands from the microcontroller, and more functions are available than in the stand-alone mode. The MSM6789A/6789L can directly drive serial voice ROM as external memory as well as serial register or general-purpose DRAM* (1-bit ¥ or 4-bit ¥ type selectable) as external memories, which allows a recording and playback circuit with fixed messages to be built easily. The method from microcontroller is the same as the MSM6788. * Only for MSM6789A Difference between MSM6788 and MSM6789A MSM6788 MSM6789A General DRAM Unavailable Available Unvoiced-part elimination function No Yes PCM playback No Yes SBC method: The SBC method divides voice frequencies into five bands and codes the component for each of the bands separately, as shown below. @fs=8.0 Hz Gain ch 1 ch 2 ch 3 ch 4 ch 5 3 kHz 0 1 2 f (Hz) Note: This data sheet explains a stand-alone mode and a microcontroller interface mode, separately. MSM6789A/6789L ¡ Se...