HS HS16032A

The HS16032A Chinese graphic LCD module uses ST7920 as the control driver, and its software features are primarily determined by the ST7920 controller driver. The ST7920 serves as both controller and driver, providing 33 COM outputs and 64 SEG outputs. With the ST7921 driver, it can drive up to 256×32 dot matrix LCD.

The hardware features of the HS16032A Chinese graphic LCD module are as follows:

• Selectable 8-bit, 4-bit parallel interface and serial interface
• Parallel interface compatible with M6800 timing
• Automatic power-on reset
• Built-in internal oscillator
• 64×16-bit character display RAM (DDRAM supports up to 16 characters × 4 rows; LCD display range: 16×2 rows)
• 2M-bit Chinese character ROM (CGROM) with 8192 Chinese characters (16×16 dot matrix)
• 16K-bit half-width character ROM (HCGROM) with 126 alphanumeric characters (16×8 dot matrix)
• 64×16-bit character generator RAM (CGRAM)
• ICON RAM with 15×16 bits, totaling 240 dots

The software features of the HS16032A Chinese graphic LCD module are as follows:

• Mixed text and graphics display
• Screen clear
• Cursor home
• Display on/off
• Cursor display/hide
• Character blinking
• Cursor shift
• Display shift
• Vertical screen scroll
• Reverse display
• Sleep mode

Chinese character ROM selection: ST7920-0A has a built-in BIG-5 Traditional Chinese character ROM; ST7920-0B has a built-in GB Simplified Chinese character ROM. Users must specify which version is required before ordering.

The HS16032A provides two interface options: serial interface J1 and parallel interface J2. Some lines in J2 can also be used for serial communication. Users can select serial or parallel interface by configuring the PSB pin. Alternatively, the PSB pin can be left floating, and the interface can be selected via the solder jumpers on the back of the LCD module. Shorting J6 selects serial interface; shorting J5 selects parallel interface. Never short J5 and J6 simultaneously, as this will cause a short circuit and damage the LCD module.

J9~J12 are used to select the polarity of the backlight control pins. The default configuration is pin 18 positive and pin 19 negative, with J9 and J10 shorted. If users need to change the backlight control pin polarity, J9 and J10 must be opened and J11 and J12 shorted instead. Users are discouraged from modifying the solder jumpers themselves, as any improper operation may cause the LCD to malfunction or become damaged. Adjustments may only be made during the prototype stage with assistance from a technician. For mass production, please inform the manufacturer of your requirements, and the factory will configure accordingly before shipment. Apart from J5, J6, and J9~J12, users should never modify any other solder jumpers.

The ST7920 has a built-in voltage doubler circuit that generates a voltage twice that of Vref. Vref is derived from VCC through resistor voltage division, where Vref ≤ VCC. The doubled voltage is output from the Vout pin and supplied to V0 via the module's circuitry to drive the LCD. V0 directly drives the LCD — the higher the V0 voltage, the deeper the contrast. Contrast is adjusted by varying the V0 value. Users can connect a 20K adjustable resistor between V0 and GND to pull down the V0 voltage. For LCD modules with fixed contrast, contrast adjustment is not available. Attempting to adjust contrast using the above method will only reduce the contrast.

The ST7920 character generator ROM provides 8192 Chinese characters in 16×16 dot matrix format and 126 alphanumeric characters in 16×8 dot matrix format. It uses 2 bytes for encoding selection. By writing the character encoding to DDRAM, the hardware automatically retrieves and displays the corresponding character from CGROM.

The ST7920 character generator RAM provides a user-defined character (custom character) function with space for 4 sets of 16×16 dot matrix characters. Users can define characters not available in CGROM into CGRAM.

The display RAM provides 64×2 bytes of space, capable of controlling up to 4 rows of 16 Chinese characters. When writing to the display data RAM, characters from CGROM, HCGROM, or CGRAM can be displayed respectively.

Character type selection:

• Display half-width characters: write a 1-byte encoding to DDRAM, in the range 02~7FH
• Display CGRAM characters: write a 2-byte encoding to DDRAM; four encodings available: 0000H, 0002H, 0004H, and 0006H
• Display Chinese characters: write a 2-byte encoding to DDRAM — high byte first, then low byte; range is A140H~D75FH (BIG5) or A1A0H~F7FFH (GB)

The ST7920 provides 240-dot ICON display, consisting of 15 IRAM units, each 16 bits wide. When writing to each IRAM unit, first write the IRAM address, then send 2 consecutive bytes of data — high byte first (D15~D8), followed by low byte (D7~D0).

The graphic RAM provides 64×32 bytes of space (GDRAM address set by extended instruction), supporting a maximum 256×64 dot matrix 2D graphics buffer. When modifying the graphic RAM, set the GDRAM address using extended instructions — vertical address first, then horizontal address (2 consecutive bytes define the vertical and horizontal addresses), followed by 2 bytes of data written to the graphic RAM (high byte first, then low byte).