Daewoo DTC-29M5ME Service Manual

Contents

-32-Pin 35, VERT Vertical Sawtooth Output (Fig. 6–20)This pin supplies the drive signal for the vertical outputstage. The drive signal is generated with 15-bit preci-sion. The analog voltage is generated by a 4 bit cur-rent-DAC with external resistor and uses digital noiseshaping.Pin 36, EW East-West Parabola Output (Fig. 6–21)This pin supplies the parabola signal for the East-Westcorrection. The drive signal is generated with 15 bitprecision. The analog voltage is generated by a 4 bitcurrent-DAC with external resistor and uses digitalnoise shaping.Pin 37, SENSE Measurement ADC Input (Fig. 6–23)This is the input of the analog to digital converter for thepicture and tube measurement. Three measurementranges are selectable with RSW1 and RSW2.Pin 38, GNDM Measurement ADC Reference InputThis is the ground reference for the measurement A/Dconverter. Connect this pin to GNDPin 39, 40, RSW1, RSW2 Range Switch for Measur-ing ADC (Fig. 6–22)These pins are open drain pull-down outputs. RSW1 isswitched off during cutoff and whitedrive measure-ment. RSW2 is switched off during cutoff measurementonly.Pin 41, SVMOUT Scan Velocity Modulation Output(Fig. 6–15)This output delivers the analog SVM signal. The D/Aconverter is a current sink like the RGB D/A convert-ers. At zero signal the output current is 50% of themaximum output current.Pin 42, 43, 44, ROUT, GOUT, BOUT Analog RGBOutput (Fig. 6–15)These pins are the analog Red/Green/Blue outputs ofthe back-end. The outputs are current sinks.Pin 45, VSUPAB* Supply Voltage, Analog Back-endThis pin has to be connected to the analog supply volt-age. No supply current for the digital stages should flowthrough this line.Pin 46, GNDAB* Ground, Analog Back-endThis pin has to be connected to the analog ground. Nosupply current for the digital stages should flow throughthis line.Pin 47, VRD DAC Reference Decoupling (Fig. 6–24)Via this pin the DAC reference voltage is decoupled byan external capacitor. The DAC output currents dependon this voltage, therefore a pull-down transistor can beused to shut off all beam currents. A decouplingcapacitor of 4.7 F in parallel to 100 nF (low inductance)is required.Pin 48, XREF DAC Current Reference (Fig. 6–24)External reference resistor for DAC output currents,typical 10 k ßŸ to adjust the output current of the D/Aconverters. (see recommended operating conditions).This resistor has to be connected to analog ground asclosely as possible to the pin.Pin 49, 50, 51, AIN13 Analog Audio Input (Fig. 6–25)The analog input signal from TUNER or SCART is fedto this pin. The input signal must be AC-coupled. Alter-natively these pins can be used as digital input port(Fig. 6–25).Pin 52, 53, AOUT1, AOUT2 Analog Audio Output (Fig.6–26)These pins are the analog audio outputs. Connectionsto these pins must use a 680 ohm series resistor asclosely as possible to these pins. The output signals areintended to be AC coupled. Alternatively these pins canbe used as digital input port (Fig. 6–26).Pin 54, VSUPS* Supply Voltage, StandbyPin 55, GNDS* Ground, StandbyThis is the ground reference for the standby circuitry.Pins 56 and 57, XTAL1 Crystal Input and XTAL2 Crys-tal Output (Fig. 6–7)These pins are connected to an 20.25 MHz crystaloscillator which is digitally tuned by integrated shuntcapacitances. The CLK20 clock signal is derived fromthis oscillator.Pin 58, RESQ Reset Input/Output (Fig. 6–6)A low level on this pin resets the VCT 38xxA/B. Theinternal CPU can pull down this pin to reset externaldevices connected to this pin.Pin 59, SCL I 2C Bus Clock (Fig. 6–6)This pin connects to the I2C bus clock line. The signalcan be pulled down by external slave ICs to slow downdata transfer.Pin 60, SDA I 2 C Bus Data (Fig. 6–6)This pin connects to the I2C bus data line.Pin 6164, P20P23 I/O Port (Fig. 6–27)These pins provide CPU controlled I/O ports.IC DESCRIPTION VCT 38xxA/B