TS87C51RC2 ATMEL Corporation, TS87C51RC2 Datasheet - Page 62

• Manufacturer Part Number: TS87C51RC2
• Description: High Performance 8-bit Microcontroller 32 Kbytes Otp
• Manufacturer: ATMEL Corporation

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:T
T
T
T
T
T
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 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:
Example:
T
62
LLPL
A
A
A
A
LLIV
ALE / PSEN
Freq (MHz)
Port 1, 2, 3
= 0 to +70 C (commercial temperature range); V
= -40 C to +85 C (industrial temperature range); V
= 0 to +70 C (commercial temperature range); V
= -40 C to +85 C (industrial temperature range); V
T (ns)
Port 0
in X2 mode for a -V part at 20 MHz (T = 1/20
= Time for ALE Low to PSEN Low.
AVLL
x= 22 (Table 38.)
T= 50ns
T
LLIV
= 2T - x = 2 x 50 - 22 = 78ns
= Time for Address Valid to ALE Low.
Table 35. Max frequency for derating formula regarding the speed grade
-M X1 mode
40
25
Table 34. Load Capacitance versus speed range, in pF
100
100
-M
80
-M X2 mode
20
50
-V X1 mode
SS
SS
E6
SS
SS
40
25
= 0 V; V
= 0 V; 2.7 V < V
= 50 ns):
= 0 V; V
= 0 V; 2.7 V < V
50
50
30
-V
CC
-V X2 mode
CC
= 5 V
33.3
30
= 5 V
CC <
CC <
10%; -M and -V ranges.
5.5 V; -L range.
10%; -M and -V ranges.
5.5 V; -L range.
-L X1 mode
33.3
30
Rev. C - 06 March, 2001
100
100
80
-L
-L X2 mode
20
50