Texas Instruments TMS320 Interrupts and subroutines, External interface, Multiprocessing

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TMS320 SECOND-GENERATION

DEVICES

SPRS010B Ð MAY 1987 Ð REVISED NOVEMBER 1990

interrupts and subroutines

The TMS320C2x has three external maskable user interrupts INT2-INT0, available for external devices that interrupt the processor. Internal interrupts are generated by the serial port (RINT and XINT), by the timer (TINT), and by the software interrupt (TRAP) instruction. Interrupts are prioritized with reset (RS) having the highest priority and the serial port transmit interrupt (XINT) having the lowest priority. All interrupt locations are on two-word boundaries so that branch instructions can be accommodated in those locations if desired.

A built-in mechanism protects multicycle instructions from interrupts. If an interrupt occurs during a multicycle instruction, the interrupt is not processed until the instruction is completed. This mechanism applies to instructions that are repeated and to instructions that become multicycle due to the READY signal.

external interface

The TMS320C2x supports a wide range of system interfacing requirements. Program, data, and I/O address spaces provide interface to memory and I/O, thus maximizing system throughput. I/O design is simplified by having I/O treated the same way as memory. I/O devices are mapped into the I/O address space using the processor's external address and data buses in the same manner as memory-mapped devices. Interface to memory and I/O devices of varying speeds is accomplished by using the READY line. When transactions are made with slower devices, the TMS320C2x processor waits until the other device completes its function and signals the processor via the READY line. Then, the TMS320C2x continues execution.

A full-duplex serial port provides communication with serial devices, such as codecs, serial A/D converters, and other serial systems. The interface signals are compatible with codecs and many other serial devices with a minimum of external hardware. The serial port may also be used for intercommunication between processors in multiprocessing applications.

The serial port has two memory-mapped registers: the data transmit register (DXR) and the data receive register (DRR). Both registers operate in either the byte mode or 16-bit word mode, and may be accessed in the same manner as any other data memory location. Each register has an external clock, a framing synchronization pulse, and associated shift registers. One method of multiprocessing may be implemented by programming one device to transmit while the others are in the receive mode. The serial port on the TMS320C25 is double-buffered and fully static.

multiprocessing

The flexibility of the TMS320C2x allows configurations to satisfy a wide range of system requirements and can be used as follows:

•A standalone processor

•A multiprocessor with devices in parallel

•A slave/host multiprocessor with global memory space

•A peripheral processor interfaced via processor-controlled signals to another device.

For multiprocessing applications, the TMS320C2x has the capability of allocating global data memory space and communicating with that space via the BR (bus request) and READY control signals. Global memory is data memory shared by more than one processor. Global data memory access must be arbitrated. The 8-bit memory-mapped GREG (global memory allocation register) specifies part of the TMS320C2x's data memory as global external memory. The contents of the register determine the size of the global memory space. If the current instruction addresses an operand within that space, BR is asserted to request control of the bus. The length of the memory cycle is controlled by the READY line.

The TMS320C2x supports DMA (direct memory access) to its external program/data memory using the HOLD and HOLDA signals. Another processor can take complete control of the TMS320C2x's external memory by asserting HOLD low. This causes the TMS320C2x to place its address data and control lines in a high-impedance state, and assert HOLDA. On the TMS320C2x, program execution from on-chip ROM may proceed concurrently when the device is in the hold mode.

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Contents Description TMS320 SECOND-GENERATION Digital Signal ProcessorsSignals Definition PGA and PLCC/CER-QUAD PIN AssignmentsFunction PIN Introduction Bit-Reversed Indexed-Addressing Mode for Key Features TMS32020Memory Space Wait States for Communication to Slower Off-ChipTMS320 Second-Generation Device Overview ArchitecturePackage TypeSECOND-GENERATION Devices Functional block diagram TMS320C2xScaling shifter Timer16 ⋅ 16-bit parallel multiplier Memory controlMemory Maps TMS320 SECOND-GENERATION DevicesInterrupts and subroutines External interfaceMultiprocessing Repeat feature Instruction setAddressing modes Instruction Symbols Symbol DefinitionInstruction set summary TMS320C25 Instruction Set Summary XOR SUBT²XORK² ZACLPH ² ApacLTA LTP ²Data Memory Operations Mnemonic Description Words TMS320C25 Instruction Set Summary concluded TMS32020 Product Notification TMS32020Development support TMS320 Second-Generation Software and Hardware Support Software Tools Part NumberHardware Tools Part Number Documentation support Specification overviewRecommended operating conditions MIN NOM MAX UnitParameter Test Conditions MIN TYP§ MAX Unit Clock Characteristics and Timing Internal clock optionExternal clock option Test Load Circuit Parameter MIN TYP MAX Unit Memory and Peripheral Interface TimingRS, INT, BIO, and XF Timing Hold TimingHold Holda Serial Port Timing INT Clkin / Clkx / Clkr MP/MC IOHTMS320C25GBA Parameter Test Conditions MIN TYP MAX Unit Clkin External Clock OptionVOH Min TdC1L-AL Low after CLKOUT1 low Serial Port Timing See Notes 14 Eprom ProgrammingVPP IPP1INT0 INT2 VIH CLKIN, CLKX, ClkrMP/MC VIL CLKOUT1, CLKOUT2 Internal Clock Option External clock optionFcrystal TdC1-S From Clkout if Is present TsuIN Setup before CLKOUT1 high Clock characteristics and timing Contrast Summary of Electrical SpecificationsParameter MIN TYP MAXRS, INT, BIO, and XF timing Memory and peripheral interface timingHold timing Serial port timingClock timing Timing DiagramsMemory read timing BR, PS, D SReady CLKOUT1 CLKOUT2 Strb Memory write timingMSC One wait-state memory access timingIack Reset timingInterrupt timing TMS320C25 Interrupt timing TMS32020Serial port transmit timing Serial port receive timingExternal flag timing BIO timingPC = N PC = N + Hold Hold timing part aHolda ExecuteHold timing part B CLKOUT1 CLKOUT2Holda Fetch Fetch Execute Or is D15-D0 TdHH-AH TMS320C25FNL Plcc reflow soldering precautions Typical Supply Current Characteristics for TMS320C25Mechanical Data Pin GB grid array ceramic package TMS32020, TMS320C25Parameter MAX Unit Advance Jedec NO. Outline Terminals MIN MAX Fast programming and verification Programming the TMS320E25 Eprom cellVCC Pin Nomenclature TMS320E25EPT EPT VPPSignal TMS320E25 Programming Mode LevelsProgram Read Output Name ² PIN Verify Inhibit Disable ErasureProgram verify Fast Programming FlowchartOutput disable ReadROM protection and verification Eprom protect TMS320E25 Protect and Verify Eprom Mode LevelsVIH VIL PGM VPP VCC VSS Clkin EPT VPPRbit EpromVCC VIH VIL PGM VIH/VOH HI-Z VIL/VOL VPP EPT VSS VIH VIL VPP VCCTMS320 SECOND-GENERATION NIL Other Qualified Versions of TMS320C25 Packaging InformationImportant Notice
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