Maramar Circuit diagram for LCD interfacing with microcontroller is shown in the above figure. Thanku for ur explanation and code. Quote and Order boards in minutes on https: Some important command instructions are given below: All the pins are clearly understandable by their name and functions, except the control pins, so they are explained below:. Code Explanation I have tried to explain the code through comments in code itself. Log in or register to post Comment.
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Data Flow There are two types of architecture in data flow. They are : Von Neumann Architecture Harvard Architecture One shared memory is only available for instructions program and data instructions and data have to be fetched in sequential order in case of Von Neumann architecture.
The Harvard architecture on the other hand uses physically separate memories for their instructions 8 and data, requiring dedicated buses for each of them. Instructions and Operands can therefore be fetched simultaneously.
A CISC microprocessor contains a more complex set of instructions that it responds to and some of these instructions cannot be completed in one machine cycle. RISC This is a type of architecture that recognizes a relatively limited number of instructions. Until the mids, the tendency among computer manufacturers was to build increasingly complex CPUs that had ever-larger sets of instructions.
At that time, however, a number of computer manufacturers decided to reverse this trend by building CPUs capable of executing only a very limited set of instructions. One advantage of reduced instruction set computers is that they can execute their instructions very fast because the instructions are so simple. Application sophistication can also range from simple application control to high-speed machine control and data collection.
For these reasons, the microcontroller vendors have established extensive families of similar models. To use the pins of port 0 as both input and output ports, each pin must be connected externally to a 10K pull-up resistor. This is due to the fact that P0 is an open drain, unlike P1,P2,P3. When 1s are written to port 0 pins, they can be used as high impedance inputs. It receives code bytes during flash programming.
It is bidirectional port with internal pull ups. When 1s are written to port 1, they can be used as inputs. It receives low order address bytes during flash programming and verification. Port 2 It occupies a total of 8 pins It is a bidirectional port with internal pull ups.
It emits higher order address bytes during fetches from external program memory and during accesses to external data memory that uses 16 bit address. It receives higher order address bits and control signals during flash programming and verification.
Port 3 It occupies a total of 8 pins When 1s are written to port 3, they are used as inputs. It also receives control signals during flash programming and verification. Port 3 has the additional function of providing some extremely important signals such as interrupts.
Bits 3. Pins 3. A high on this pin normally low for two machine cycles while the oscillator is running resets the device. This is often referred to as Power-On reset. Activating a power-on reset will cause all values in the registers to be lost. It will set Program Counter to all 0s. XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. This pin is also the program pulse input PROG during flash programming.
EA must be strapped to ground in order to enable the device to fetch code from external program memory locations.
EA should be strapped to Vcc for internal program executions. It also receives the 12V programming enable voltage during flash programming.
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