The display contains a variety of signals. Signal from the hub board, through the line to the Unit board or module, the completion of data transmission. In addition to the data signal is serial transmission, the other signals are parallel transmission. Now the various signal functions are analyzed as follows:
(1) CLK clock signal: A shift pulse provided to the shift register, each of which causes the data to be moved in or out of a digits. The data on the data port must coordinate with the clock signal to transmit the data normally, the frequency of the data signal must be 1/2 times the frequency of the clock signal. In any case, when the clock signal is abnormal, the whole board is displayed in disorder.
(2) STB latch signal: When the data transmission is complete, the STB latch signal is valid, the data in the shift register is locked, and its data content is displayed by the driving circuit. However, because the driving circuit is controlled by EN, the premise of the light must be enabled. The latch signal also needs to be coordinated with the clock signal to display a complete image. In any case, when the latch signal has an exception, the whole board is shown to be cluttered.
(3) en enable the signal: the whole screen brightness control signal, also used for screen blanking. The change in brightness can be controlled as long as the duty ratio is adjusted. When the signal can be abnormal, the whole screen will appear light, dark or trailing phenomenon.
(4) Color data signal: Provide the data needed to display the image. Must be coordinated with the clock signal to transfer data to any one of the display points. Generally in the display of red and green data signal separation, if a data signal short-circuit to the positive or negative, then the corresponding color will appear bright or not bright, when the data signal is suspended when the corresponding color display uncertainty.
(5) ABCD signal: Only exist when dynamic scan is displayed, ABCD is actually binary number, A is the lowest, if the use of binary to indicate the maximum range of ABCD signal control is 16 rows (0000-1111), 1/4 scan as long as the AB signal can be, because the AB signal range is 4 lines (00-11). When the line control signal is abnormal, there will appear dislocation, highlighting or overlap of images and so on.