AT89C55WD-33AC ATMEL Corporation, AT89C55WD-33AC Datasheet - Page 32

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

Serial Port Timing: Shift Register Mode Test Conditions
The values in this table are valid for V
Shift Register Mode Timing Waveforms
AC Testing Input/Output Waveforms
Note:
Float Waveforms
Note:
32
Symbol
t
t
t
t
t
XLXL
QVXH
XHQX
XHDX
XHDV
INSTRUCTION
WRITE TO SBUF
OUTPUT DATA
INPUT DATA
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 occurs. A port pin begins to
CLEAR RI
AT89C55WD
min. for a logic 1 and V
float when a 100 mV change from the loaded V
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
(1)
0
IL
t
V
QVXH
max. for a logic 0.
V
LOAD
CC
CC
- 0.5V
0.45V
t
= 4.0V to 5.5V and Load Capacitance = 80 pF.
1
XHDV
V
V
0
LOAD
LOAD
VALID
CC
+ 0.1V
- 0.1V
- 0.5V for a logic 1 and 0.45V for a logic 0. Timing measurements are made at V
2
t
XLXL
t
1
XHQX
OH
VALID
(1)
Timing Reference
/V
OL
0.2 V
0.2 V
TEST POINTS
3
level occurs.
Points
t
Min
700
1.0
2
XHDX
50
0
12 MHz Osc
VALID
CC
CC
+ 0.9V
- 0.1V
4
3
Max
700
VALID
V
V
OL
OL
5
- 0.1V
+ 0.1V
4
VALID
10t
2t
12t
CLCL
CLCL
Min
Variable Oscillator
0
CLCL
6
-133
-80
5
VALID
7
10t
6
VALID
CLCL
Max
-133
SET TI
SET RI
1921B–MICRO–09/02
8
7
VALID
Units
µs
ns
ns
ns
ns
IH