TS87C51RD2 ATMEL Corporation, TS87C51RD2 Datasheet - Page 63

• Manufacturer Part Number: TS87C51RD2
• Description: (TS8xC51Rx2) High Performance 8-bit Microcontroller
• Manufacturer: ATMEL Corporation

4188E–8051–08/06
T
T
Table 11-3. 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 11-3.
Table 11-5., Table 39. and Table 42. give the description of each AC symbols.
Table 11-6., Table 11-8. and Table 11-10. give for each range the AC parameter.
Table 11-7., Table 11-9. and Table 11-11. give the frequency derating formula of the AC param-
eter. 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 11-4.
Example:
T
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
T (ns)
Port 0
in X2 mode for a -V part at 20 MHz (T = 1/20
x= 22 (Table 11-7.)
T= 50ns
T
Load Capacitance versus speed range, in pF
Max frequency for derating formula regarding the speed grade
LLIV
-M X1 mode
= 2T - x = 2 x 50 - 22 = 78ns
40
25
100
100
-M
80
-M X2 mode
20
50
-V X1 mode
40
25
E6
SS
= 50 ns):
SS
= 0 V; 2.7 V < V
-V
50
50
30
= 0 V; 2.7 V < V
-V X2 mode
33.3
30
AT/TS8xC51Rx2
CC <
-L X1 mode
CC <
33.3
30
5.5 V; -L range.
5.5 V; -L range.
100
100
80
-L
-L X2 mode
20
50
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