Texas Instruments TMS320 Internal Clock Option, Parameter Test Conditions MIN TYP MAX Unit

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TMS320C25, TMS320E25

ADVANCE INFORMATION

SPRS010B Ð MAY 1987 Ð REVISED NOVEMBER 1990

CLOCK CHARACTERISTICS AND TIMING

The TMS32025 can use either its internal oscillator or an external frequency source for a clock.

internal clock option

The internal oscillator is enabled by connecting a crystal across X1 and X2/CLKIN (see Figure 2). The frequency of CLKOUT1 is one-fourth the crystal fundamental frequency. The crystal should be either fundamental or overtone mode, and parallel resonant, with an effective series resistance of 30 Ω, a power dissipation of 1 mW, and be specified at a load capacitance of 20 pF. Note that overtone crystals require an additional tuned LC circuit; see the application report, Hardware Interfacing to the TMS320C25 (SPRA014A).

	PARAMETER	TEST CONDITIONS	MIN TYP	MAX	UNIT

fx	Input clock frequency	TA = 0°C to 70°C	6.7	40.96	MHz
f	Serial port frequency	T = 0°C to 70°C	0 ²	5 120	MHz
xs		A
C1, C2		TA = 0°C to 70°C	10		pF

²The serial port was tested at a minimum frequency of 1.25 MHz. However, the serial port was fully static but will properly function down to fsx = 0 Hz.

X1X2/CLKIN

Crystal

C1C2

Figure 2. Internal Clock Option

external clock option

An external frequency source can be used by injecting the frequency directly into X2/CLKIN with X1 left unconnected. The external frequency injected must conform to the specifications listed in the following table.

switching characteristics over recommended operating conditions (see Note 3)

			PARAMETER			MIN	TYP	MAX	UNIT

tc(C)	CLKOUT1/CLKOUT2 cycle time					97.7		597	ns
td(CIH-C)	CLKIN high to CLKOUT1/CLKOUT2/STRB				high/low	5		30	ns
td(CIH-C)	CLKIN high to CLKOUT1/CLKOUT2/STRB				high/low	5		30	ns
tf(C)	CLKOUT1/CLKOUT2/STRB		fall time					5	ns
tf(C)	CLKOUT1/CLKOUT2/STRB		fall time					5	ns
tr(C)	CLKOUT1/CLKOUT2/STRB		rise time					5	ns
tr(C)	CLKOUT1/CLKOUT2/STRB		rise time					5	ns
tw(CL)	CLKOUT1/CLKOUT2 low pulse duration					2Q ± 8	2Q	2Q + 8	ns
tw(CH)	CLKOUT1/CLKOUT2 high pulse duration					2Q ± 8	2Q	2Q + 8	ns
td(C1-C2)	CLKOUT1 high to CLKOUT2 low, CLKOUT2 high to CLKOUT1 high, etc.					Q ± 5	Q	Q + 5	ns

NOTE 3: Q = 1/4tc(C).

28	POST OFFICE BOX 1443 • HOUSTON, TEXAS 77001

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Contents TMS320 SECOND-GENERATION Digital Signal Processors DescriptionPGA and PLCC/CER-QUAD PIN Assignments Signals DefinitionFunction PIN Introduction Key Features TMS32020 Bit-Reversed Indexed-Addressing Mode forMemory Space Wait States for Communication to Slower Off-ChipArchitecture TMS320 Second-Generation Device OverviewPackage TypeFunctional block diagram TMS320C2x SECOND-GENERATION DevicesTimer Scaling shifter16 ⋅ 16-bit parallel multiplier Memory controlTMS320 SECOND-GENERATION Devices Memory MapsExternal interface Interrupts and subroutinesMultiprocessing Instruction set Repeat featureAddressing modes Symbol Definition Instruction SymbolsInstruction set summary TMS320C25 Instruction Set Summary SUBT² XORXORK² ZACApac LPH ²LTA LTP ²Data Memory Operations Mnemonic Description Words TMS320C25 Instruction Set Summary concluded TMS32020 TMS32020 Product NotificationDevelopment support Software Tools Part Number TMS320 Second-Generation Software and Hardware SupportHardware Tools Part Number Specification overview Documentation supportMIN NOM MAX Unit Recommended operating conditionsParameter Test Conditions MIN TYP§ MAX Unit Internal clock option Clock Characteristics and TimingExternal clock option Test Load Circuit Memory and Peripheral Interface Timing Parameter MIN TYP MAX UnitHold Timing RS, INT, BIO, and XF TimingHold Holda Serial Port Timing MP/MC IOH INT Clkin / Clkx / ClkrTMS320C25GBA Parameter Test Conditions MIN TYP MAX Unit External Clock Option ClkinVOH Min TdC1L-AL Low after CLKOUT1 low Serial Port Timing Eprom Programming See Notes 14VPP IPP1CLKIN, CLKX, Clkr INT0 INT2 VIHMP/MC VIL Internal Clock Option External clock option CLKOUT1, CLKOUT2Fcrystal TdC1-S From Clkout if Is present TsuIN Setup before CLKOUT1 high Contrast Summary of Electrical Specifications Clock characteristics and timingParameter MIN TYP MAXMemory and peripheral interface timing RS, INT, BIO, and XF timingHold timing Serial port timingTiming Diagrams Clock timingBR, PS, D S Memory read timingReady Memory write timing CLKOUT1 CLKOUT2 StrbOne wait-state memory access timing MSCReset timing IackInterrupt timing TMS32020 Interrupt timing TMS320C25Serial port receive timing Serial port transmit timingBIO timing External flag timingPC = N PC = N + Hold timing part a HoldHolda ExecuteCLKOUT1 CLKOUT2 Hold timing part BHolda Fetch Fetch Execute Or is D15-D0 TdHH-AH Typical Supply Current Characteristics for TMS320C25 TMS320C25FNL Plcc reflow soldering precautionsPin GB grid array ceramic package TMS32020, TMS320C25 Mechanical DataParameter MAX Unit Advance Jedec NO. Outline Terminals MIN MAX Programming the TMS320E25 Eprom cell Fast programming and verificationPin Nomenclature TMS320E25 VCCEPT EPT VPPTMS320E25 Programming Mode Levels SignalProgram Read Output Name ² PIN Verify Inhibit Disable ErasureFast Programming Flowchart Program verifyRead Output disableROM protection and verification TMS320E25 Protect and Verify Eprom Mode Levels Eprom protectVIH VIL PGM VPP VCC VSS Clkin EPT VPPEprom RbitVIH VIL VPP VCC VCC VIH VIL PGM VIH/VOH HI-Z VIL/VOL VPP EPT VSSTMS320 SECOND-GENERATION NIL Packaging Information Other Qualified Versions of TMS320C25Important Notice