Electronic evaluation of new projects

Mar 1, 2021 | Articles

A. Assessment of interface definitions

The individual PIN definitions coming out of the display must be consistent with the PIN definitions connected to the customer’s motherboard.
The following is a 37pin interface definition
Pin No. Symbol Description Note
1 GND Ground —
2 VCI(2.8V) Power Supply Input
3 IOVCC(1.8V/2.8V) Power Supply Input
4 /CS Chip select signal pin Input
5 RS Register select signal pin Input
6 /WR Write signal pin Input
7 /RD Read signal pin Input
8 /RESET Reset signal Input
9 DB0 Data bus pin Input / Output
10 DB1 Data bus pin Input / Output
11 DB2 Data bus pin Input / Output
12 DB3 Data bus pin Input / Output
13 DB4 Data bus pin Input / Output
14 DB5 Data bus pin Input / Output
15 DB6 Data bus pin Input / Output
16 DB7 Data bus pin Input / Output
17 DB8 Data bus pin Input / Output
18 DB9 Data bus pin Input / Output
19 DB10 Data bus pin Input / Output
20 DB11 Data bus pin Input / Output
21 DB12 Data bus pin Input / Output
22 DB13 Data bus pin Input / Output
23 DB14 Data bus pin Input / Output
24 DB15 Data bus pin Input / Output
25 (LCM_ID) LCM Identify select pin Input
26 Y-YD Touch panel down pin Input
27 X-XR Touch panel right pin Input
28 Y+YU Touch panel up pin Input
29 X+XL Touch panel left pin Input
30 LED-A LED anode for all LED Input
31 LED-1 LED cathode for LED1 Input
32 LED-2 LED cathode for LED2 Input
33 LED-3 LED cathode for LED3 Input
34 LED-4 LED cathode for LED4 Input
35 GND Ground -.
36 GND Ground -.
37 IM0 Select the MPU system interface
mode Input

B. LCD Interface Method

There are two common interface methods: CPU (also called MCU 8080 system) and RGB interface.
CPU interface: is the most common mode for small and medium-size, generally 8080 system, parallel data transfer.
It can be 8-bit, 9-bit, 16-bit, 18-bit, etc., easy and convenient to control, but requires GRAM.
RGB interface: the large screen adopts more modes, the data transmission is also divided into 6, 16, 18 bit, etc., relatively speaking.
Serial transmission of data is slower, but has the advantage of fewer interface signal lines and takes up fewer resources.

C. Drive current-voltage confirmation

Determine the drive voltage according to the LCD Panel and the SPEC of the IC, e.g. VDD, VCI, according to the backlight LED
The control IC and the corresponding current and voltage values of the LEDs are determined in series or in parallel.

D. FPA, PCB wiring space assessment

Depending on the size of the product, determine whether the FPA, PCB meets the design requirements.
Adequacy of the approximate component area.
FPA minimum line width, and whether the line spacing meets the requirements.
The PCB component space is sufficient.

E. ESD assessment

In addition to adding ESD-resistant circuits to the design, the product itself needs to be protected against static electricity. In particular. Protective measures at IC locations.

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