![]() Cheap 1602 16x2 hd44780, Buy Quality character lcd directly from China 16x2 hd44780 Suppliers: 1602 16x2 HD44780 Character LCD /w IIC/I2C Serial Interface Adapter Module Enjoy Free Shipping Worldwide! Limited Time Sale Easy Return. Features for 1602 LCD: LCD display module with green backlight. Wide viewing angle and high contrast. Built-in industry standard HD44780 equivalent LCD. Windows 7 mouse drivers. HD44780 based LCD displays are very popular for embedded projects because they are cheap, easy to interface, can display characters, consume power lot less than seven-segment displays, and most of the present day compilers have in-built library routines for them. However, the only disadvantage is that they require at least 6 I/O pins of microcontroller. Well, you may ask, isn’t that less than what seven-segment displays require? Yes, that’s true but there are circumstances where you don’t have left enough pins for LCD display. For example, if you are going to design a temperature sensor based on a PIC12F683 microcontroller, which has just 6 I/O pins, you won’t have pins for interfacing a LCD. One solution for cases like that is to use serial LCD’s. ![]() Serial LCD’s available in the market cost more than double of HD44780 based standard one. The serial LCD’s still have the standard LCD module but it has an extra built-in driver module that receives data/command from a host microcontroller in serial format and convert it to appropriate parallel format suitable for HD44780 driver input. The goal of this project is to show how to make a 3-wire serial LCD driver for low pin-count microcontrollers like PIC12F series using a serial-in parallel-out shift register (74HC595 in this case). PIC12F683 has been chosen here to test the end product. Since 74HC595 is just a shift register with no intelligence of its own, the burden goes to the host microcontroller (PIC12F683) to appropriately transfer the LCD character/command data and control signals in serial format. This part of the intelligence is embedded in the firmware inside PIC12F683. So, a portion of program flash memory inside PIC12F683 is sacrificed for this purpose. The required three pins of PIC12F683 performs following functions. • Serial data transfer to 74HC595 • Clock signal for the Shift/Storage register • Enable signal to HD44780 LCD Module 74HC595 Shift Register 74HC595 is a high-speed 8-bit serial in, serial/parallel-out shift register. It also has a storage register and 3-state outputs. The two registers (shift and stoarge) have separate clocks, SH_CP and ST_CP respectively. Data in the shift register is shifted on the positive-going transitions of SH_CP, and the content of shift register will be transferred to the storage register on a positive-going transition of the ST_CP. If both the clocks are together, the shift register will be one clock ahead of the storage register. The output enable (OE) pin, when pulled Low, enables the 8-bit data of the storage register to show up at the parallel output (Q0-Q7). Keygen edison 54. SH_CP and ST_CP clocks are tied together for this purpose and are driven together by a microcontroller pin. So, the storage register output (Q0-Q7) is 1 clock behind the shift register, and an additional clock pulse is required after the last bit is fed to the serial input so that it would appear at the output.
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