AT89C51-12AC ATMEL [ATMEL Corporation], AT89C51-12AC Datasheet - Page 14

• Manufacturer Part Number: AT89C51-12AC
• Description: 8-bit Microcontroller with 4K Bytes Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Serial Port Timing: Shift Register Mode Test Conditions
(V
Shift Register Mode Timing Waveforms
AC Testing Input/Output Waveforms
Note:
14
Symbol
t
t
t
t
t
XLXL
QVXH
XHQX
XHDX
XHDV
CC
V
CC
= 5.0 V 20%; Load Capacitance = 80 pF)
INSTRUCTION
- 0.5V
0.45V
WRITE TO SBUF
OUTPUT DATA
1. AC Inputs during testing are driven at V
INPUT DATA
CLEAR RI
logic 1 and 0.45V for a logic 0. Timing measurements
are made at V
logic 0.
CLOCK
Parameter
Serial Port Clock Cycle Time
Output Data Setup to Clock Rising Edge
Output Data Hold after Clock Rising Edge
Input Data Hold after Clock Rising Edge
Clock Rising Edge to Input Data Valid
ALE
IH
min. for a logic 1 and V
0.2 V
0.2 V
TEST POINTS
AT89C51
CC
0
CC
t
QVXH
+ 0.9V
- 0.1V
t
1
XHDV
0
VALID
CC
IL
max. for a
- 0.5V for a
2
t
XLXL
t
1
XHQX
VALID
(1)
3
t
XHDX
2
Min
700
12 MHz Osc
1.0
50
VALID
Float Waveforms
Note:
0
V
LOAD
4
Max
700
1. For timing purposes, a port pin is no longer floating
3
VALID
when a 100 mV change from load voltage occurs. A
port pin begins to float when 100 mV change from
the loaded V
V
V
LOAD
LOAD
5
10t
+ 0.1V
- 0.1V
2t
4
12t
VALID
CLCL
CLCL
Min
0
CLCL
Variable Oscillator
-117
OH
-133
Timing Reference
6
/V
(1)
OL
5
VALID
Points
level occurs.
10t
7
CLCL
6
Max
VALID
-133
SET TI
SET RI
V
V
OL
8
OL
- 0.1V
+ 0.1V
7
VALID
Units
µs
ns
ns
ns
ns