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SGH-X450 Circuit Description
2-3
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3. Backlight LED Driver
The backlight LED driver is a low-side, programmable current source designed to control the brightness of the keyboard
and LCD illumination.
LED1_DRV is controlled via LED1_[0:2] and can be programmed to sink from 15mA to 60mA in
7.5mA steps. LED2_DRV is controlled via LED2_[0:2] and can be programmed to sink from 5mA to 40mA in 5mA steps.
Both LED drivers are capable of sinking their maximum output current at a worst-case maximum output voltage of 0.6V.
For efficient use, the LEDs is connected between the battery and the LED_DRV output.
4. Vibrator Motor Driver
The vibrator motor driver is a low-side, programmable voltage source designed to drive a small dc motor that silently
alerts the user of an incoming call. The driver is controlled by VIB[0:1] and can be programmed to maintain a motor
voltage of 1.3V, 2.0V, or 2.5V(relative to VBAT) while sinking up to 100mA. For efficient use, the vibrator motor should
be connected between the main battery and the VIB_DRV output.
2) Connector
1. LCD Connector
LCD is consisted of main LCD(color 65K UFB LCD). Chip select signals of EMI part in the trident, CLCD_EN, can
enable main LCD. LED_EN signal enables white LED of main LCD and EL_EN signal enables dimming mode
of main LCD.
These two signals are from IO part of the DSP in the trident. RST signal from 2106 initiates the initial process of the
LCD.
16-bit data lines(D(0)~D(15)) transfers data and commands to LCD through emi_filter. Data and commands use A(2) signal.
If this signal is high, Inputs to LCD are commands. If it is low, Inputs to LCD are data. The signal which informs the
input or output state to LCD, is required. But this system is not necessary this signal. So CP_WEN signal is used to
write data or commands to LCD.
Power signals for LCD are +VBATT and VCCD.
SPK1P and SPK1N from CSP1093 are used for audio speaker. And YMU_VIB_EN from MA-3 enables the motor.
2. JTAG Connector
Trident has two JTAG ports which are for ARM core and DSP core(DSP16000). So this system has two port connector
for these ports. Pins' initials for ARM core are 'CP_' and pins' initials for DSP core are 'DSP_'.
CP_TDI and DSP_TDI signal are used for input of data. CP_TDO and DSP_TDO signals are used for the output of the
data. CP_TCK and DSP_TCK signals are used for clock because JTAG communication is a synchronous. CP_TMS and
DSP_TMS signals are test mode signals. The difference between these is the RESET_INT signal which is for ARM core
RESET.