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Adv ance informa t ion, Contrast summary of electrical specifications, Clock characteristics and timing – Texas Instruments TMS320 User Manual

Page 39

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PARAMETER

UNIT

TMS320C25 50

SPRS010B — MAY 1987 — REVISED NOVEMBER 1990

POST OFFICE BOX 1443

HOUSTON, TEXAS 77001

39

SERIAL PORT TIMING

switching characteristics over recommended operating conditions (see Note 3)

PARAMETER

MIN

TYP

MAX

UNIT

t

d(CH-DX)

DX valid after CLKX rising edge (see Note 18)

75

ns

t

d(FL-DX)

DX valid after falling edge (TXM = 0, see Note 18)

40

ns

t

d(CH-FS)

FSX valid after CLKX raising edge (TXM = 1)

40

ns

NOTES: 3. Q = 1/4 t

c(C)

18. The last occurrence of FSX falling and CLKX rising.

timing requirements over recommended operating conditions (see Note 3)

MIN

NOM

MAX

UNIT

t

c(SCK)

Serial port clock (CLKX/CLKR) cycle time

160

ns

t

f(SCK)

Serial port clock (CLKX/CLKR) fall time

25

ns

t

r(SCK)

Serial port clock (CLKX/CLKR) rise time

25

ns

t

w(SCK)

Serial port clock (CLKX/CLKR) low or high pulse duration (see Note 19)

64

ns

t

su(FS)

FSX or FSR setup time before CLKX, CLKR falling edge (TXM = 0)

5

ns

t

h(FS)

FSX or FSR hold time before CLKX, CLKR falling edge (TXM = 0)

10

ns

t

su(DR)

DR setup time before CLKR falling edge

5

ns

t

h(DR)

DR hold time after CLKR falling edge

10

ns

The 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
f

sx

= 0 Hz.

Value derived from characterization data and not tested.

NOTES: 3. Q = 1/4 t

c(C)

19. The cycle of the serial port must be within 40%-60%.

CONTRAST SUMMARY OF ELECTRICAL SPECIFICATIONS

The following table presents electrical parameters which differ between TMS320C25 (40 MHz, 100 ns) and

TMS320C25-50 (50 MHz, 80 ns).

clock characteristics and timing

TMS320C25

TMS320C25-50

MIN

TYP

MAX

MIN

TYP

MAX

t

c(SCK)

97.7

597

78.13

597

ns

t

d(CIH-C)

5

30

12

27

ns

t

f(C)

5

4

ns

t

r(C)

5

4

ns

t

w(CL)

2Q -- 8

2Q

2Q + 8

2Q -- 7

2Q + 3

ns

t

w(CH)

2Q -- 8

2Q

2Q + 8

2Q -- 3

2Q + 7

ns

t

d(C1-C2)

Q -- 5

Q

Q + 5

Q -- 6

Q + 2

ns

t

su(S)

5

Q -- 5

4

Q -- 4

ns

t

h(S)

8

4

ns

ADV

ANCE

INFORMA

T

ION