Conversation with Merlin [email protected] · Sat Nov 18 2023

explain 8288 bus controller in detail its features how it works and its pins

The 8288 bus controller is a crucial component of the Intel 8086/8088 microprocessor system, primarily used in maximum mode operations, multiprocessor configurations, or with coprocessors. You can find a comprehensive explanation of its features, functionality, and pin configuration below:

Features:

  1. Command Generation: The 8288 generates necessary control signals for the 8086/8088 microprocessor system. It handles the generation of clock and bus control signals required for communication between multiple processors and coprocessors.
  2. Bus Control Signals: The 8288 is responsible for the generation of various bus control signals, such as Address Latch Enable (ALE), Data Transmit/Receive (DT/R), Data Enable (DEN), and MCE/PDEN (Master Cascade Control/Peripheral Data Enable), which ensures efficient data transfer and control.
  3. Command Enable (CEN): The input signal CEN determines the state of command outputs of the 8288, facilitating memory partitioning implementation and addressing conflicts between system and resident bus devices.
  4. Address Enable (AEN): AEN is an input signal that enables the command outputs of the 8288 a specified duration after it becomes active. This signal affects the command lines in the I/O bus mode.
  5. IOB (Input/Output Bus) Mode: This input signal determines whether the 8288 functions in the I/O bus mode or the system bus mode, influencing its operational behavior.

How it Works: The 8288 bus controller, when used in conjunction with the 8086 microprocessor in maximum mode, assists in the orchestration of command and bus control signals essential for proper system functioning. It acts as a central coordinator, generating and managing the various signals required for effective communication between the microprocessor and other system components, including memory and I/O devices.

Pins:

  1. S0, S1, S2: These are status input pins, receiving the corresponding signals from the 8086 microprocessor.
  2. CLK: This is the input signal for the clock.
  3. A: Input signal for Address Enable.
  4. CEN: Input signal for Command Enable.
  5. IOB: Input signal determining the mode of operation.
  6. MRDC, MWTC, AMWC IORC, IOWC, AIOWC, INTA: Output signals representing various command signals and interrupt acknowledgment.
  7. DT/R, DEN, MCE/PDEN, ALE: Output signals representing bus control signals.

By effectively managing these signals and inputs, the 8288 bus controller plays a pivotal role in coordinating inter-device communication and control within the microprocessor system, ensuring smooth and efficient operation.

Please let me know if you need further details on any specific aspect of the 8288 bus controller.

8288 Bus Controller 1. Draw the pin diagram of 8288. 2. Draw the functional block diagram of 8288. Ans. The functional block diagram of 8288 is shown in Fig. 19a.2. 3. Is 8288 always used with 8086? Ans. No, the bus controller IC 8288 is used with 8086 when the latter is used in MAX mode. 4. What are the inputs to 8288? Ans. There are two sets of inputsthe first set is the status inputs S0 , S1 and S2 . The second set is the control inputs having the following signals: CLK, AEN, CEN and IOB. 5. What are the output signals from 8288? Ans. There are two sets of output signalsMultibus command signals and the second set includes the bus control signalsAddress Latch, Data Transreceiver and Interrupt Control Signals. The multibus command Signals are the Conventional MEMR, MEMW, IOR and IOW signals which have been renamed as MRDC, MWTC, IORC, IOWC, where the suffix C stands for command. INTA signal is also included in this. Two more signals AMWC and AIOWC are the advanced memory and I/O write commands. These two output signals are enabled one clock cycle earlier than normal write commands. Some memory and I/O devices require this wider pulse width. The bus control signals are DT/ R , DEN, ALE and MCE/ PDEN . The first three are identical to 8086 output signals when operated in the MIN modewith the only difference here is that the DEN output signal of 8288 is an active high signal. MCE/ PDEN (Master Cascade Control/Peripheral Data Enable) is an output signal having two functionsI/O bus control or system bus control. When this signal status is low, its function is identical to DEN signal and it operates in I/O mode. When high, this signal ensures the sharing of the system buses by other processors connected to the system. In the system bus control mode, the signals AEN (address enable) and IOB both have to be low. This then permits more than one 8288 and 8086 to be interfaced to the same set of system buses. In this case, the bus arbiter IC 8289 selects the active processor by enabling only one 8288, via the AEN input. In this system bus mode MCE/ PDEN signal becomes MCE-Master Cascade Control and is used during an interrupt sequence to read the address from a master priority interrupt controller (PIC). The operating modes of 8288 are determined by CEN (command enable), IOB, (I/O bus) and AEN signals and shown in Table 19a.1. 6. Discuss the status pins S2 , S1 and S0 . Ans. These are three input pins for 8288 and come from the corresponding pins of 8086 (its output pins). The command-decode definitions for various combinations of the three signals are shown in Table 19a.2. 7. Discuss the three pins (a) IOB (b) CEN and (c) AEN of 8288. Ans. (a) IOB stands for input/output bus mode and is an input signal for 8288. When IOB = high, 8288 functions in the I/O bus mode and when IOB = low, 8288 functions in the system bus mode. (b) CEN stands for command enable and is an input signal for 8288. When CEN = low, all command outputs of 8288 and the DEN and the PDEN control outputs are forced into active state and not tri-stated. This feature is utilised for memory partitioning implementation. This also eliminates address conflicts between system bus devices and resident bus devices. Again, when CEN = high, these outputs are in the enabled state. (c) AEN stands for address enable and is an input signal for 8288. This signal enables command outputs of 8288 a minimum of 110 ns (and a maximum of 250 ns) after it becomes low (i.e., active). If AEN = 1, then command output drivers are put to tri-state. In the I/O bus mode (IOB = 1) AEN signal does not affect the command lines.

8051-microcontrollers.blogspot.com

From Wikipedia, the free encyclopedia Intel 8288 Pinout of 8288 The Intel 8288 is a bus controller designed for Intel 8086/8087/8088/8089. The chip is supplied in 20-pin DIP package. The 8086 (and 8088) operate in maximum mode, so they are configured primarily for multiprocessor operation or for working with coprocessors. Necessary control signals are generated by the 8288. It was used in the IBM PC, XT and its clones.[1] IBM PC AT used its successor Intel 82288. Pin assignment and function for the control lines[edit] Name Pin Input(I),Output(O) Function VCC 20 Input power (+5V) GND 10 Ground (0V) S0, S1, S2 19,3,18 I Status input CLK 2 I Clock AEN 6 I Address Enable CEN 15 I Command Enable IOB 1 I Input/Output Bus Mode MRDC 7 O Memory Read Command MWTC 9 O Memory Write Command AMWC 8 O Advanced Memory Write Command IORC 13 O I/O Read Command IOWC 11 O I/O Write Command AIOWC 12 O Advanced I/O Write Command INTA 14 O Interrupt Acknowledge DT/R 4 O Data Transmit/Receive DEN 16 O Data Enable MCE/PDEN 17 O MCE (if IOB is LOW), PDEN (if IOB is HIGH) ALE 5 O Address Latch Enable Variants[edit] Both Intel 8288 and I8288 (industrial grade) version were available for US$14.30 and $33.75 in quantities of 100 respectively.[2][3] The available 82C88 CMOS version was outsourced to Oki Electronic Industry Co., Ltd.[4] The package version of Intel 82C88 branded in 20-pin PLCC of sampling at fourth quarter of 1985.[5] References[edit] ^ "The structure of the original IBM PC's motherboard". tu-chemnitz.de. Archived from the original on June 6, 2014. Retrieved July 5, 2022. ^ The 8086 Family: Concepts and realities, Intel Preview Special Issue: 16-Bit Solutions, Intel Corporation, May/June 1980, page 19 ^ 8086 Available for industrial environment, Intel Preview Special Issue: 16-Bit Solutions, Intel Corporation, May/June 1980, page 29 ^ Intel Corporation, "NewsBit: Intel Licenses Oki on CMOS Version of Several Products", Solutions, July/August 1984, Page 1. ^ Ashborn, Jim; "Advanced Packaging: A Little Goes A Long Way", Intel Corporation, Solutions, January/February 1986, Page 2 External links[edit] 8288 Bus-Controller data sheet

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Write short note on 8288 Bus Controller. 1 Answer The minimum mode signals, INTA, ALE, DEN, DT/ IT, M/ 10 , WR , HLDA, and HOLD (on pins 24 to 31) that are essential for interfacing memory and I/O devices, are not available in the system if the 8086 is operated in maximum mode. An 8288 bus controller is used to generate the relevant signals for interfacing memory and I/O devices in the maximum mode. Figure (a) gives the block diagram of 8288. The bus controller has a command signal generator and a control signal generator. Figure (b) illustrates the maximum mode configuration of 8086 and the use of 8288 in 8086 based system. The 8288 input and output signals: SO, SL and S2: The inputs (8086 Status outputs) are decoded to generate command signals. AEN: A low Address Enable signal activates the memory control signals. CEN: The Control Enable signal enables the 8288 command outputs. IOB: High on the I/O Bus input operates the 8288 in the I/O bus mode in systems where there are separate system bus and I/O bus. CLK: The Clock input DEN: The Data bus Enable signal controls the data bus buffers in the system. This signal is active-high in contrast to the DEN signal in the minimum mode. ALE: The Address Latch Enable signal is used to de-multiplex address and data lines signals. DT/R: The Data Transmit/Receive signal controls bidirectional data bus buffer. MRDC, MWTC, IORC and lOWC: The 8288 generates the normal Memory Read, Memory Write, I/O Read, I/O Write Control signals. AMWC, and AIOWC: These are Advanced Memory and Advanced I/O Write Control signals. INTA: The Interrupt Acknowledge output. MCE/PDEN: The Master Cascade Enable/Peripheral Data Enable output serves dual function. If IOB input is low it selects cascading of interrupt controllers, and if high enables the I/0 bus transceivers. Please log in to add an answer.

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