AT89C55WD-33AU ATMEL [ATMEL Corporation], AT89C55WD-33AU Datasheet - Page 30

• Manufacturer Part Number: AT89C55WD-33AU
• Description: 8-bit Microcontroller with 20K Bytes Flash
• Manufacturer: ATMEL [ATMEL Corporation]

34. Serial Port Timing: Shift Register Mode Test Conditions
The values in this table are valid for V
35. Shift Register Mode Timing Waveforms
36. AC Testing Input/Output Waveforms
37. Float Waveforms
30
Symbol
t
t
t
t
t
XLXL
QVXH
XHQX
XHDX
XHDV
INSTRUCTION
WRITE TO SBUF
OUTPUT DATA
INPUT DATA
CLEAR RI
AT89C55WD
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
Note:
Note:
(1)
0
t
V
QVXH
V
1. AC Inputs during testing are driven at V
1. For timing purposes, a port pin is no longer floating when a 100 mV change from load voltage
LOAD
CC
CC
measurements are made at V
occurs. A port pin begins to float when a 100 mV change from the loaded V
occurs.
- 0.5V
0.45V
t
= 4.0V to 5.5V and Load Capacitance = 80 pF.
1
XHDV
V
V
LOAD
0
LOAD
VALID
+ 0.1V
- 0.1V
2
t
XLXL
t
1
XHQX
VALID
Timing Reference
0.2 V
0.2 V
TEST POINTS
(1)
3
Points
t
Min
700
XHDX
1.0
2
50
0
12 MHz Osc
VALID
CC
CC
IH
+ 0.9V
- 0.1V
min. for a logic 1 and V
4
3
Max
700
VALID
CC
V
- 0.5V for a logic 1 and 0.45V for a logic 0. Timing
V
OL
OL
5
- 0.1V
+ 0.1V
4
VALID
10t
2t
12t
CLCL
CLCL
Min
Variable Oscillator
0
CLCL
IL
6
-133
-80
max. for a logic 0.
5
VALID
7
10t
6
VALID
CLCL
Max
-133
SET TI
OH
SET RI
1921D–MICRO–6/08
8
/V
OL
7
VALID
level
Units
ns
µs
ns
ns
ns