datasheet, circuit, data sheet: INTEL – PROGRAMMABLE INTERVAL TIMER,alldatasheet, datasheet, Datasheet search site for Electronic. from Intel Corporation. Find the PDF Datasheet, Specifications and Distributor Information. The Intel 82C54 is a high-performance CHMOS version of the industry standard programmable The 82C54 is pin compatible with the HMOS and is a superset of the NOTICE This is a production data sheet The specifi-.
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OUT will then go high again, and the whole process repeats itself. The first byte of the new count when loaded in the count register, stops the previous count.
The time between the high pulses depends on the preset count in the counter’s register, and is calculated using the following formula:. In dataseet mode can be used as a Monostable multivibrator. The Intel 82c54 variant handles up to 10 MHz clock signals.
Retrieved 21 August Mode 0 is used for the generation of accurate time delay under software control. Retrieved from ” https: The one-shot pulse can be repeated without rewriting the same count into the counter. The value is held until it dafasheet read out or overwritten. In this mode can be used as Monostable 8523.
To initialize the counters, the microprocessor must write a control word CW in this register. This prevents any serious alternative uses of the timer’s second counter on many x86 systems.
According to a Microsoft document, “because reads from and writes to this hardware  require communication through an IO port, programming it takes several cycles, nitel is prohibitively expensive for the OS.
This mode is similar to mode 2. The is described in the Intel “Component Data Catalog” publication. The control word register contains 8 bits, labeled D Counting rate is equal to the input clock frequency. This page was last edited on 27 Septemberat The counting process will start after the PIT has received these messages, and, in some cases, if it detects the rising edge from the GATE input signal.
However, in free-running counter applications such as in the x86 PC, it is necessary to first write a latch command for the desired channel to the control register, so ingel both bytes read will belong to one and the same value. GATE input is used as trigger input. After writing the Control Word and initial count, dtasheet Counter is armed.
Intel has the same pinout.
However, the duration of the high and low clock pulses of the output will be different from mode 2. There are 6 modes in total; for modes 2 and 3, the D3 bit is ignored, so the missing modes 6 and 7 are aliases for modes 2 and 3. D0 D7 is the MSB. The three counters are bit down counters independent of each other, and can be easily read by the CPU. The time between the high pulses depends on the preset count in the datasheef register, and is calculated using the following formula:.
The counting process will start after the PIT has received these messages, and, in some cases, if it detects the rising edge from the GATE input signal. The is implemented in HMOS and dataseet a “Read Back” command not available on theand permits reading and writing ijtel the same counter to be interleaved.
Datasheet(PDF) – Intel Corporation
OUT will be initially high. Most values set the parameters for one of the three counters:.
Once programmed, the channels operate independently. OUT remains low until the counter reaches 0, at which point OUT will be set high until the counter is reloaded or the Control Word is written. Bits 5 through 0 are the same as the last bits written to the control register. Once the device detects a rising edge on the GATE input, it will start counting.
This is a holdover of the very first CGA PCs — they derived all necessary frequencies from a single quartz crystaland to make TV output possible, this quartz had to run at a multiple of the NTSC color subcarrier frequency. Timer Channel 2 is assigned to the PC speaker. If a new count is written to the Counter during a oneshot pulse, the current one-shot is not affected unless the counter is retriggered.
To initialize the counters, the microprocessor must write a control word CW in this register.
OUT will go low on the Clock pulse following a trigger to begin the one-shot pulse, and will remain low until the Counter reaches zero. This is a holdover of the very first CGA PCs — they derived all necessary frequencies from a single quartz crystaland to make TV output possible, this oscillator had to run at a multiple of the NTSC color subcarrier frequency. Datsheet channel can be programmed to operate in one of six modes.
In this mode, the counter will start counting from the initial COUNT value loaded into it, down to 0. D0, where D7 is the MSB. The counter will then generate a low pulse for 1 clock cycle a strobe — after that the output will become high again.