Panasonic EB-GD90 Technical Manual

Also see for EB-GD90: Operating instructions

Contents

http://cxema.ruBASEBAND OVERVIEWIssue A Section 6 MCUK990801G8Revision 0 – 28 – Technical Guide6.2.6 Real Time ClockThe Real Time Clock (RTC) and Alarm function is provided by U604 running at 32,768 MHz. It interfaces to the CPU via a fourserial lines: CE (chip enable), SCLK (serial clock), SI (serial input) and SO (serial output). To maintain power to the clock whenthe main battery is removed, a small rechargeable back-up battery (VBACKUP) is used. This power source also provides powerback-up for data held in the SRAM.The RTC can be calibrated using a high-precision oscillation adjustment function. This gives a maximum adjustment range of±189.2 ppm in increments of 3 ppm. Addition functions of the RTC are date, alarm, periodic interrupt, 32 kHz output, supplyvoltage monitoring and oscillation halt sensing.6.2.7 MicrophoneTo provide improved speech pick-up, noise immunity and reduced echo, the microphone is a noise cancelling type. The GSMstandard requires that when in Handheld mode the sending audio frequency response must fit within the mask shown below.Figure 6.4: Handheld GSM Transmit Audio frequency response maskWhen using the Handsfree feature GSM requires that the sending audio frequency response must fit within the mask shownbelow.Figure 6.5: Handsfree GSM Transmit Audio frequency response maskdB5-100-5-15100 1000 10000Frequency (Hz)10069-1dB5-100-5-15100 1000 10000Frequency (Hz)10070-1