AKI-H8-based LCD driver circuit design

The LCD of the H8 board of the autumn ventors is M1632 and SC1602BS because it is very simple to operate as a character monochrome display. In the circuit design, it allows the port as much as possible to 4BIT and 8BIT in two modes, but also to output data to this LCD only if you only need to connect to 4 I \ O ports. IN0, IN1, IN2, IN3, IN4, IN7 in the above figure correspond to port of 0, 1, 2, 3, 4, and 7 ports in PB ports. And from the 1-14 encoding of the chip can find the corresponding logical function number from the hardware pattern. PB0 PB1 PB2 PB3 PB4 PB7 DB4 DB5 DB6 DB7 RS E DB4-DB7 is the data / command input port, RS is the data / command control bit, and E is the level control bit. As can be seen from the circuit diagram, the 5th slor R / W port is hardly linked to the GND end, always input to 0, so always the write mode, the status information of the LCD cannot be acquired. (1): Initialization This film requires the application for three execution data lengths in the hardware (not unknown), after which the position is adjusted to 4. There is a place to pay attention to, the hardware is 8 bits. When the width mode, it doesn't know that the situation on the board is the fact that the other four do not have a link chip. It is only accepted by 8, then the fourth place is always 0. Only the DB4-DB7 of the same table. efficient. After adjusting the bit width to 4, you can receive the input two times in extreme time, once a low 4 digits is high, and you can start a detailed setting of the LCD operating mode. For (i = 0; i "3; i ++) { LCDOUT8 (0,0x3); / * Three application 8-bit wide mode * / } LCDOUT8 (0,0x2); / * Apply 4-bit wide mode * / LCDOUT4 (0,0x28); / * 4BIT mode, Shift mode * / LCDOUT4 (0,0x0e); / * Open, cursor Open, ブ ブ ン ク * / LCDOUT4 (0,0x06); / * Use memory in an increment * / LCDOUT4 (0,0x01); / * Clear LCD display * / LCDOUT4 (0,0x02); / * Move cursor to the start bit * / According to the conclusions obtained by the source code of the manufacturer, there is still a very unclear place. Why still use 0x3,0x2 numbers when 8-bit mode, they should not be received by LCD reception in 8-bit mode. (2) Write an LCD I haven't talked about E, and it almost exists in every place in the LCD, because no matter what modification is to be modified from 1 to 0, it is said that no matter whether it is. What settings are to call the function code to e-modified to be implemented. In addition, in the four-bit mode, it is transmitted to the LCD twice. Static void Lcdout4 (int RS, INT Code) 2 { 3 int stat; INT PB; CHAR LB, HB; Pb = Pb.dr; IF (rs) stat = (PB & LCDMASK) | LCD_RS; Else Stat = (PB & LCDMASK); HB = ((Code "" 4) & 0xF) | LB = (Code & 0xF) | Pb.dr = HB | LCD_E; Pb.dr = Hb; Pb.dr = lb | lcd_e; Pb.dr = lb; Pb.dr = Pb; Wait (4); } Edit: hfy, read full text

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