RTD2523 Datasheet, PDF (21/129 Pages) List of Unclassifed Manufacturers – Zoom scaling up and down

Realtek
RTD2523/2513
4.9 The Programmable Schmitt Trigger of HSYNC
To get better waveform of the input HSYNC, we have a programmable Schmitt Trigger circuit.
For different HSYNC amplitude and polarity, we can select different setting of the threshold voltage.
The V_t+ and the V_t- can be selected by register 0xED.
We can select the old mode or the new mode. When using the new mode we can directly
determine the positive threshold voltage (1.4V, 1.6V… 2.6V), and we can choose the distance from
the V_t+ to determine the V_t- (0.6V, 0.8V, 1.0V, 1.2V). We also can finely tune the voltage by minus
0.1V. For application, we can select different threshold voltage by the polarity of the HSYNC. The
control register is 0xED.
Input HSYNC
V_t+
V_t-
Output HSYNC
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Figure 18 The Schmitt Trigger Behavior Diagram
4.10 Crystal Frequency Output
RTD can output crystal frequency or half crystal frequency to external MCU to save a crystal
device. After power on, RTD latch the state of PLL_TEST2 pin to determine which frequency to
output, and the result shows in TCON register address 0x00[0]. 0 is for half of crystal frequency and
1 is for crystal frequency. When power on, crystal frequency output to TCON12 and TCON13.
Hence, crystal-in pin of external MCU can connect to TCON12 or TCON13. Firmware can turn off
the signal output of other pin, and the control register is in TCON register 0x00[1] and 0x00[2].
4.11 Pin Out Configuration
RTD supports TTL, LVDS and RSDS output interface. After power on, display port is high
impedance. Firmware can set its control register in TCON address 0x03[7:6] to select output
interface. Refer to Pin Out Diagram for output pin definition.
RSDS interface
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