Kenwood TS-990S Service Manual

Also see for SP-990: Instruction manual

Contents

TS-990S38CIRCUIT DESCRIPTION10-7. USB Interface (host)This transceiver incorporates a 2-channel USB hostfunction and supports USB 2.0 at full speed. The main ap-plication MCU (IC1) and USB transceiver (IC502) confi guresa single channel and the main application MCU and USBtransceiver (IC503) confi gures another single channel.The USB bus power supply uses the HIGH SIDE switch(IC501) for over-current detection. The interface of the mainapplication MCU and USB transceiver (IC502 and IC503)performs 6-pin serial communications.10-8. DVI outputThis transceiver incorporates a DVI-I terminal with analogand digital video output functions.The DVI transmitter (IC401) converts RGB888 digital sig-nals from the main application MCU (IC1) so that digital im-age signals will be output from the DVI-I terminal (J401) viathe digital visual interface (DVI).The video DAC (IC402) performs the D/A conversion ofRGB888 digital signals from the main application MCU sothat analog image signals will be output from the DVI-I termi-nal (J401).The output images are the same as images output fromthe main display.10-9. Recording/PlaybackThis transceiver has a recording/playback function. TheADC (IC7) performs the A/D conversion of analog signals ata sampling frequency (fs) of 16kHz after the analog signalsare input from the DSP (IC300) of the DSP unit (X53-453).The converted signals are stored in the main applicationMCU (IC1). At the time of playback, the DAC (IC6) performsthe D/A conversion of the digital audio signal memorized inthe main application MCU at an fs of 16kHz and transmitsthe converted analog signal to the DSP of the DSP unit.10-10. Sub Display InterfaceThe incorporated sub display is a 3.5-inch (320 x 240resolution) LCD. The sub application MCU (IC201) and thesub display interface are in mutual RGB888 communication.RGB888 digital signal output from the sub application MCUis transferred to the sub display.10-11. Main Display InterfaceThe incorporated main display is a 7-inch (800 x 480resolution) LCD. The interface of the main application MCU(IC1) and main display performs RGB666 communication.RGB666 digital signal output from the main application MCUis applide to the buffer ICs (IC651, IC652, and IC653) wherewaveform shaping is performed, and the signal is transferredto the main display.10-12. Operating as USB 2.0 (device)If this transceiver is connected to a PC over a USB cable,the following three items operate as high-speed USB 2.0 de-vices.• USB to UART Bridge (IC702)Used for PC command communication for the ARCP.• USB Audio (IC703)The USB audio operates at the time of signal transmis-sion and reception through the microphone and speakerconnected to the PC or recording the sound received.• Access to NAND Flash (IC8)In the case of updating firmware through the PC, thefirmware is stored temporarily in the NAND flash via themain application MCU (IC1).The above three devices are connected through theUSB-B connector (J701) on the rear panel to the PC throughthe USB 3-channel hub (IC701).11. Display CircuitThe display block consists of the panel MCU (X54-385IC6), a peripheral circuit, LCD assy, LCD backlight block,and LED block. The display block uses the PTXD, PRXD,PCTS, and PRTS to communicate with the main MCU (X53-452 IC46) and uses the PATXD to communicate with theapplication MCU (X46-339 IC1) (at a baud rate of 115,200bps).11-1. Circuits Around the Panel MCUTwo power supplies, the 5D (5 V) and 33AVR (3.3 V),are used for the digital block. The panel MCU clock at11.0592MHz (X101) is used. The reset signal is controlledfrom the main MCU. The panel MCU accepts signal thekey matrix, various encoders, various volumes, external PFkey, and the touch panel. The volumes and external PF keyare all accepted from the multiplexer (IC9, IC10, and IC11)through the A/D port of the panel MCU.11-2. Touch panelThe touch panel used for this transceiver is of resistivemembrane system. The power supply switches (Q303 toQ308) for the touch detection X/Y axis are turned ON andOFF through the panel MCU to control the touch panel.The coordinates are accepted through the A/D port of thepanel MCU based on the division ratio of the voltage appliedin the x-axis and y-axis direction.11-3. LCD Backlight ControllerThe LCD backlight controller uses IC306 on the mainside and IC307 on the sub side. The built-in driver boostsand the PWM controls the power supply to the backlight toadjust the brightness of the backlight. The panel MCU is inPWM control. The LCD backlight controller is under the ON/OFF control of three MCUs, the main MCU, the applicationMCU, and the panel MCU.11-4. LEDThe main display and sub display are under a four-stagedimmer control. The user can set four levels of brightness.The panel MCU is in control of 50 LEDs, and each LED notused for the numeric keypad is driven by a different port. Thepanel MCU and shift register (IC7) are in control of the drivetransistor.