DP8228/DP8228M/DP8238/DP8238M System Controller and Bus Driver General Description The DP8228/DP8228M, DP8238/DP8238M are system controller/bus drivers contained in a standard, 28-pin dualin-line package. The chip, which is fabricated using Schottky Bipolar technology, generates all the read and write control signals required to directly interface the memory and input/ output components of the 8080A microcomputer family. The chip also provides drive and isolation for the bidirectional data bus of the 8080A microprocessor. Data bus isolation enables the use of slower memory and input/output components in a system, and provides for enhanced system noise immunity. A user-selected signal-level interrupt vector (RST 7) is provided by the device for use in the interrupt structure of small systems that need only one basic vector. No additional components (such as an interrupt instruction port) are required to use the single interrupt vector in these systems. The devices also generate an Interrupt Acknowledge (INTA) control signal for each byte of a multibyte CALL instruction when an interrupt is acknowledged by the 8080A. This feature permits the use of a multilevel priority interrupt structure in large, interrupt-driven systems. Features Y Y Y Y Y Y Y Single chip system controller and bus driver for 8080A Microcomputer Systems Allows use of multibyte CALL instructions for Interrupt Acknowledge Provides user-selected single-level interrupt vector (RST 7) Provides isolation of data bus Supports a wide variety of system bus structures Reduces system component count DP8238/DP8238M provides advanced Input/Output Write and Memory Write control signals for large system timing control 8080A Microcomputer Family Block Diagram TL/F/6825 – 1 TRI-STATEÉ is a registered trademark of National Semiconductor Corporation. C1995 National Semiconductor Corporation TL/F/6825 RRD-B30M105/Printed in U. S. A. DP8228/DP8228M/DP8238/DP8238M System Controller and Bus Driver December 1988 Absolute Maximum Ratings Operating Conditions If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Min Max Units Supply Voltage (VCC) DP8228M, DP8238M 4.50 5.50 VDC DP8228, DP8238 4.75 5.25 VDC Operating Temperature (TA) b 55 a 125 DP8228M, DP8238M §C a 70 DP8228, DP8238 0 §C Note: Maximum ratings indicate limits beyond which permanent damage may occur. Continuous operation at these limits is not intended and should be limited to those conditions specified under DC electrical characteristics. Storage Temperature b 65§ C to a 150§ C Supply Voltage, VCC Input Voltage Output Current Maximum Power Dissipation* at 25§ C Cavity Package Molded Package b 0.5 to a 7V b 1.5V to a 7V 100 mA 2179 mW 2361 mW *Derate cavity package 14.5 mW/§ C above 25§ C; derate molded package 18.9 mW/§ C above 25§ C. Electrical Characteristics Min s TA s Max, Min s VCC s Max, unless otherwise noted Symbol VC IF Parameter Conditions Input Clamp Voltage, All Inputs VCC e Min, IC e b5 mA Input Load Current VCC e Max VF e 0.45V for DP8228, DP8238 VF e 0.40V for DP8228M, DP8238M STSTB D2 and D6 D0, D1, D4, D5 and D7 Min Typ (Note 1) Max Units 0.6 b 1.0 V All Other Inputs IR Input Leakage Current DB0–DB7 VCC e Max, VR e VCC All Other Inputs VTH Input Threshold Voltage, All Inputs VCC e 5V ICC Power Supply Current VCC e Max VOL VOH Output Low Voltage IO (OFF) IINT 250 mA 250 mA 20 mA 100 mA 2.0 V DP8228, DP8238 185 230 mA DP8228M, DP8238M 160 230 mA DP8228M, DP8238M 0.50 V DP8228, DP8238 0.45 V All Other Outputs VCC e Min, IOL e 10 mA DP8228M, DP8238M 0.50 V DP8228, DP8238 0.45 V D0–D7 VC e Min, IOL e b10 mA DP8228M, DP8238M 3.3 3.8 V DP8228, DP8238 3.6 3.8 V VCC e Min, IOH e b1 mA 2.4 3.8 V Short Circuit Current, All Outputs VCC e 5V, VO e 0V 15 OFF State Output Current All Control Outputs VCC e Max, VO e VCC All Other Outputs IOS mA mA VCC e Min, IOL e 2 mA Output High D0–D7 0.8 500 750 INTA Current VCC e Max, VO e 0.45V (See Test Conditions, Figure 3 ) Note 1: Typical values are for TA e 25§ C and typical supply voltages. 2 90 mA 100 mA b 100 mA 5 mA Capacitance* VBIAS e 2.5V, VCC e 5.0V, TA e 25§ C, f e 1 MHz Symbol Parameter Min Typ (Note 1) Max Units CIN Input Capacitance 8 12 pF COUT Output Capacitance Control Signals 7 15 pF I/O I/O Capacitance (D or DB) 8 15 pF *This parameter is periodically sampled and not 100% tested. Switching Characteristics Min s VCC s Max, Min s TA s Max Symbol Parameter DP8228M, DP8238M Conditions Min DP8228, DP8238 Max 25 Min Units Max tPW Width of Status Strobe tSS Set-Up Time, Status Inputs D0–D7 8 8 ns tSH Hold Time, Status Inuts D0–D7 5 5 ns tDC Delay from STSTB to Any Control Signal (Figure 2) tRR Delay from DBIN to Control Outputs (Figure 2) tRE Delay from DBIN to Enable/ Disable 8080 Bus (Figure 1) tRD Delay from System Bus to 8080 Bus During Read (Figure 1) tWR Delay from WR to Control Outputs (Figure 2) tWE Delay to Enable System Bus DB0–DB7 after STSTB (Figure 2) tWD Delay from 8080 Bus D0–D7 to System Bus DB0–DB7 During Write (Figure 2) tE Delay from System Bus Enable to System Bus DB0–DB7 (Figure 2) tHD HLDA to Read Status Outputs (Figure 2) tDS Set-Up Time, System Bus Inputs to HLDA 10 10 ns tDH Hold Time, System Bus Inputs to HLDA 20 20 ns 20 5 22 75 60 ns 30 30 ns 45 45 ns 45 30 ns 45 ns 30 ns 40 ns 30 ns 25 ns 60 20 5 30 5 ns 40 5 30 25 Test Conditions TL/F/6825 – 3 TL/F/6825–2 FIGURE 1. Test Load FIGURE 2. Test Load 3 TL/F/6825 – 4 FIGURE 3. INTA Test Circuit (For RST 7) Timing Diagram TL/F/6825 – 5 VOLTAGE MEASUREMENT POINTS: D0 –D7 (when outputs) Logic ‘‘0’’ e 0.8V, Logic ‘‘0’’ e 0.8V, Logic ‘‘1’’ e 3.0V. All other signals measured at 1.5V. *Advanced I/OW MEMW for 8238 only. Functional Pin Definitions The following describes the function of all of the DP8228/ DP8228M, DP8238/DP8238M pinouts. Some of these descriptions reference internal circuits. OUTPUT SIGNALS Memory Read (MEMR): When low, signals data to be loaded in from memory. The MEMR signal is generated by strobing in status word 1, 2, or 4. (Refer to status word chart.) Memory Write (MEMW): When low, signals data to be stored in memory. The MEMW signal is generated for the DP8238 by strobing in status word 3 or 5. (Refer to status word chart.) For the DP8228, the MEMW signal is generated by gating a low-level WR input with the strobed in status word 3 or 5. Input/Output Read (I/OR): When low, signals data to be loaded in from an addressed input/output device. The I/OR signal is generated by strobing in status word 6. Input/Output Write (I/OW): When low, signals data to be transferred to an addressed input/output device. The I/OW signal for the DP8238 is generated by strobing in status word 7. For the DP8238 the I/OW signal is generated by gating in a low-level WR input with the strobed in status word 7. Interrupt Acknowledge (INTA): When low, indicates that an interrupt has been acknowledged by the 8080A microprocessor. The INTA signal is generated by strobing in staus word 8 or 10. Signal Level Interrupt (RST 7): When the INTA output is tied to 12V through a 1 kX resistor, strobing in status word 8 or 10 will cause the CPU data bus outputs, when active, to go to the high state. INPUT SIGNALS Status Strobe (STSTB): Activated (low) at the start of each new machine cycle. The STSTB input is used to store a status word (refer to chart) from the 8080A microprocessor into the internal status latch of the DP8228, DP8238. The status word is latched when the STSTB returns to the high state. The 8080A outputs this status word onto its data bus during the first state (SYNC interval) of each machine cycle. Data Bus In (DBIN): When high, indicates that the 8080A data bus is in the input mode. The DBIN signal is used to gate data from memory or an input/output device onto the data bus. Write (WR): When low, indicates that the data on the 8080A data bus are stable for WRITE memory or output operation. Hold Acknowledge (HLDA): When high, indicates that the 8080A data and address buses will go to their high impedance state. When in the data bus read mode, DBIN input in the high state, a high HLDA input will latch the data bus information into the driver circuits and gate off the applicable control signal I/OR, MEMR, or INTA (return to the output high state). Bus Enable (BUSEN): Asynchronous DMA input to the internal gating array. When low, normal operation of the internal bidirectional bus driver and gating array occurs. When high, the bus driver and gating array are driven to their high impedance state. VCC Supply: a 5V. INPUT/OUTPUT SIGNALS CPU Data (D7 –D0) Bus: This bus comprises eight TRI-STATEÉ input/output lines that connect to the 8080A microprocessor. The bus provides bidirectional communica- Ground: 0V reference. 4 Functional Pin Definitions (Continued) System Data (DB7 –DB0) Bus: This bus comprises eight TRI-STATE input/output lines that connect to the memory and input/output components of the system. The internal bidirectional bus driver isolates the DB7 –DB0 Data Bus from the D7 –D0 Data Bus. tion between the CPU, memory, and input/output devices for instructions and data transfers. A status word (which describes the current machine cycle) is also outputted on this data bus during the first microcycle of each machine cycle (SYNC e logic 1). Status Word Chart Machine Cycle Instruction Fetch Memory Read Memory Write Stack Read Stack Write Input Read Output Write Interrupt Acknowledge Halt Acknowledge Interrupt Acknowledge While Halt Status Word 1 2 3 4 5 6 7 8 9 10 Data Bus Bit D7 D6 D5 D4 D3 D2 D1 D0 1 1 0 1 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 1 1 0 0 0 0 0 1 1 0 1 0 1 0 1 1 1 0 0 0 0 0 0 0 1 0 1 Control Signal MEMR MEMR MEMW MEMR MEMW I/OR I/OW INTA (none) INTA Block and Connection Diagrams Dual-In-Line Package TL/F/6825 – 7 TL/F/6825 – 6 5 Order Number DP8228J, DP8228MJ, DP8228N, DP8238J, DP8238MJ or DP8238N See NS Package Number J28A or N28B DP8228/DP8228M/DP8238/DP8238M System Controller and Bus Driver Physical Dimensions inches (millimeters) Ceramic Dual-In-Line Package (J) Order Number DP8228J, DP8228MJ, DP8238J or DP8238MJ NS Package Number J28A Molded Dual-In-Line Package (N) Order Number DP8228N or DP8238N NS Package Number N28B LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. 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