8254 is a device designed to solve the timing control problems in a microprocessor. It has 3 independent counters, each capable of handling clock inputs up to 10 MHz and size of each counter is 16 bit. It operates in +5V regulated power supply and has 24 pin signals. All modes are software programmable. The 8254 is an advanced version of 8253 which did not offered the feature of read back command.
The basic block diagram of 8254 is:
It has 3 counters each with two inputs (Clock and Gate) and one output. Gate is used to enable or disable counting. When any value of count is loaded and value of gate is set(1), after every step value of count is decremented by 1 until it becomes zero.
Depending upon the value of CS, A1 and A0 we can determine addresses of selected counter.
- To generate accurate time delay
- As an event counter
- Square wave generator
- Rate generator
- Digital one shot
- Interface 8254 PIT with 8085 microprocessor
- Microprocessor | 8255 (programmable peripheral interface)
- 8254 Control Word and Operating modes
- Programmable peripheral interface 8255
- Non Programmable I/O Ports- Intel 8212
- 8255 microprocessor operating modes
- Interrupts in 8085 microprocessor
- Registers of 8085 microprocessor
- Flag register in 8085 microprocessor
- Flag register of 8086 microprocessor
- Arithmetic instructions in 8085 microprocessor
- Logical instructions in 8085 microprocessor
- Data transfer instructions in 8085 microprocessor
- Branching instructions in 8085 microprocessor
- Arithmetic instructions in 8086 microprocessor
- Logical instructions in 8086 microprocessor
- Data transfer instructions in 8086 microprocessor
- Reset Accumulator (8085 & 8086 microprocessor)
- Process control instructions in 8086 microprocessor
- Memory Segmentation in 8086 Microprocessor
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.
Improved By : Mahesh Vangala