TS80C51RA2-VCKB datasheet(62/74 Pages) ATMEL

62 / 74 page

Rev. C - 06 March, 2001

TS80C51RA2/RD2

TS83C51RB2/RC2/RD2

TS87C51RB2/RC2/RD2

10.5. AC Parameters

10.5.1. 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 =0to+70

°C (commercial temperature range); V

SS =0V;VCC =5V ± 10%; -M and -V ranges.

TA = -40

°Cto+85°C (industrial temperature range); V

SS =0V;

VCC =5V ± 10%; -M and -V ranges.

TA =0to+70

°C (commercial temperature range); V

SS =0V;2.7V<VCC < 5.5 V; -L range.

TA = -40

°Cto+85°C (industrial temperature range); V

SS =0V;2.7V<VCC < 5.5 V; -L range.

Table 34. 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.

Table 34. Load Capacitance versus speed range, in pF

Table 36., Table 39. and Table 42. give the description of each AC symbols.

Table 37., Table 40. and Table 43. give for each range the AC parameter.

Table 38., Table 41. and Table 44. 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 35. Max frequency for derating formula regarding the speed grade

Example:

TLLIV in X2 mode for a -V part at 20 MHz (T = 1/20

E6 = 50 ns):

x= 22 (Table 38.)

T= 50ns

TLLIV=2T-x=2x50-22= 78ns

-M

-V

-L

Port 0

100

Port 1, 2, 3

ALE / PSEN

100

-M X1 mode

-M X2 mode

-V X1 mode

-V X2 mode

-L X1 mode

-L X2 mode

Freq (MHz)

T (ns)

33.3

TS80C51RA2-VCKB Datasheet(PDF) 62 Page - ATMEL Corporation

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