TS80C31X2-VCAD View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

TS80C31X2-VCAD

8-bit CMOS Microcontroller ROMless

Atmel Corporation 

TS80C31X2

7.5 AC Parameters

7.5.1 Explanation of the AC Symbols

Each timing symbol has 5 characters. The first character is always a “T” (stands for time). The other characters,

depending on their positions, stand for the name of a signal or the logical status of that signal. The following is

a list of all the characters and what they stand for.

Example:TAVLL = Time for Address Valid to ALE Low.

TLLPL = Time for ALE Low to PSEN Low.

TA = 0 to +70°C (commercial temperature range); VSS = 0 V; VCC = 5 V ± 10%; -M and -V ranges.

TA = -40°C to +85°C (industrial temperature range); VSS = 0 V; VCC = 5 V ± 10%; -M and -V ranges.

TA = 0 to +70°C (commercial temperature range); VSS = 0 V; 2.7 V < VCC < 5.5 V; -L range.

TA = -40°C to +85°C (industrial temperature range); VSS = 0 V; 2.7 V < VCC < 5.5 V; -L range.

Table 16. gives the maximum applicable load capacitance for Port 0, Port 1, 2 and 3, and ALE and PSEN signals.

Timings will be guaranteed if these capacitances are respected. Higher capacitance values can be used, but timings

will then be degraded.

Port 0

Port 1, 2, 3

ALE / PSEN

Table 16. Load Capacitance versus speed range, in pF

-M

-V

-L

100

50

100

80

50

80

100

30

100

Table 18., Table 21. and Table 24. give the description of each AC symbols.

Table 19., Table 22. and Table 25. give for each range the AC parameter.

Table 20., Table 23. and Table 26. give the frequency derating formula of the AC parameter. To calculate each

AC symbols, take the x value corresponding to the speed grade you need (-M, -V or -L) and replace this value

in the formula. Values of the frequency must be limited to the corresponding speed grade:

Table 17. Max frequency for derating formula regarding the speed grade

Freq (MHz)

T (ns)

-M X1 mode

40

25

-M X2 mode

20

50

-V X1 mode

40

25

-V X2 mode

30

33.3

-L X1 mode

30

33.3

-L X2 mode

20

50

Example:

TLLIV in X2 mode for a -V part at 20 MHz (T = 1/20E6 = 50 ns):

x= 25 (Table 20.)

T= 50ns

TLLIV= 2T - x = 2 x 50 - 25 = 75ns

Rev. C - 15 January, 2001

31

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