Theory Of Operation; Mb Board; Flat Panel Controller; Clock Generation - ViewSonic Q19wb-3 Service Manual

6. THEORY OF OPERATION

This section describes the function of the LCD monitor per functional block.19" monitor includes MB
board (including audio board function inside), inverter board, (including adapter function inside) and button board.

6.1 MB BOARD

The MB board is a two-layer, single-landed design with ground and ground planes provided.
The VGA cable is a signal cable that contains video signal, sync signal and DDC signal from PC VGA adapter
This system board consists of 3 functional areas : flat panel controller, Micro controller and audio controller.
6.1.1 Flat panel controller...... TSUM16AK-LF-1 (U4)
The heart of the system board is Mstar TSUM16AK-LF-1. The TSUM16AK-LF-1 is a graphics processing IC for
LCD monitor. It provides all key IC control functions required for LCD panel. On-chip functions include a
high-speed triple-ADC , PLL, high sacling engine Micro processor and OSD controller ,manages other devices in
the system such as the keypad, the backlight, LED and audio general purpose input/output pins.
Pin number
23
24
25
26
27
28
29
30
31
35
69
78
21
36
37
65
66
a)

Clock Generation :

Crystal Input Clock (XTALI and XTAL). This is the input pair to an internal crystal oscillator andcorresponding
logic. A 14.318 MHz crystal is recommended.
b) Hardware Reset ( Pin 19 )
Hardware Reset signal is generated by TSUM16AK-LF-1 (U4/Pin 19).It assert a reset signal at least 1 ms.
ViewSonic Corporation
Pin name
GPIO_P00/SAR1
GPIO_P01/SAR2
GPIO_P02/SAR3
GPIO_P03
GPIO_P06
GPIO_P07
PWM0/GPIO_P26
GPIO_P13
GPIO_P14
GPIO_P16/PWM2
GPIO_P15/PWM0
PWM2/GPIO_P24
PWM1/GPIO_P25
DDCD_SDA
DDCD_SCL
DDCA_SDA/RS232_TX
DDCA_SCL/RS232_RX
17
Pin function
Key-Menu
Key-Sel/Auto
Key-Power on/off
Key-Right
Key-Left
Key-Down(NC)
Key-Up(NC)
LED-Green
LED-Orange
Audio-MUTE(NC)
Audio-Stby-Power
Audio-Volume
Backlight-adi
SDA-VGA (Debug)
SCL-VGA (Debug)
SDA(Debug)
SDA(Debug)
Confidential - Do Not Copy
Q19wb-3