AT89 ATMEL Corporation, AT89 Datasheet - Page 13

• Manufacturer Part Number: AT89
• Description: 8-Bit Microcontroller with 4K Bytes Flash
• Manufacturer: ATMEL Corporation

Serial Port Timing: Shift Register Mode Test Conditions
(V
Shift Register Mode Timing Waveforms
AC Testing Input/Output Waveforms
Note:
Symbol
t
t
t
t
t
XLXL
QVXH
XHQX
XHDX
XHDV
CC
V
CC
= 5.0 V
INSTRUCTION
- 0.5V
0.45V
WRITE TO SBUF
OUTPUT DATA
1.
INPUT DATA
CLEAR RI
AC Inputs during testing are driven at V
a logic 1 and 0.45V for a logic 0. Timing measure-
ments are made at V
max. for a 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
20%; Load Capacitance = 80 pF)
ALE
0.2 V
0.2 V
TEST POINTS
IH
CC
CC
0
t
min. for a logic 1 and V
QVXH
+ 0.9V
- 0.1V
t
1
XHDV
0
VALID
CC
- 0.5V for
2
t
XLXL
t
1
XHQX
VALID
(1)
IL
3
Float Waveforms
Note:
t
XHDX
2
Min
700
12 MHz Osc
1.0
VALID
50
0
V
LOAD
4
1.
Max
700
3
VALID
V
V
For timing purposes, a port pin is no longer floating
when a 100 mV change from load voltage occurs. A
port pin begins to float when 100 mV change from
the loaded V
LOAD
LOAD
+ 0.1V
- 0.1V
5
10t
2t
4
12t
CLCL
VALID
CLCL
Min
CLCL
0
OH
Variable Oscillator
Timing Reference
-117
(1)
-133
/V
6
OL
Points
5
VALID
level occurs.
10t
7
CLCL
6
Max
VALID
V
V
-133
OL
OL
SET TI
SET RI
8
- 0.1V
+ 0.1V
7
VALID
Units
ns
ns
ns
ns
s
4-41