AT89LS51 Atmel Corporation, AT89LS51 Datasheet - Page 26

• Manufacturer Part Number: AT89LS51
• Manufacturer: Atmel Corporation

Specifications of AT89LS51

• Flash (kbytes): 4 Kbytes
• Max. Operating Frequency: 16 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Uart: 1
• Sram (kbytes): 0.125
• Operating Voltage (vcc): 2.7 to 4.0
• Timers: 2
• Isp: SPI
• Watchdog: Yes

29. Serial Port Timing: Shift Register Mode Test Conditions
The values in this table are valid for V
30. Shift Register Mode Timing Waveforms
31. AC Testing Input/Output Waveforms
Note:
32. Float Waveforms
Note:
26
Symbol
t
t
t
t
t
XLXL
QVXH
XHQX
XHDX
XHDV
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
AT89LS51
INSTRUCTION
min. for a logic 1 and V
float when a 100 mV change from the loaded V
WRITE TO SBUF
OUTPUT DATA
INPUT DATA
CLEAR RI
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
CLOCK
ALE
(1)
IL
max. for a logic 0.
0
t
V
QVXH
V
LOAD
CC
CC
- 0.5V
= 2.7V to 4.0V and Load Capacitance = 80 pF.
0.45V
t
1
XHDV
V
V
LOAD
0
LOAD
VALID
CC
+ 0.1V
- 0.5V for a logic 1 and 0.45V for a logic 0. Timing measurements are made at V
- 0.1V
2
t
XLXL
t
1
OH
XHQX
VALID
/V
Timing Reference
OL
0.2 V
0.2 V
TEST POINTS
(1)
3
level occurs.
Points
t
Min
700
XHDX
2
1.0
50
VALID
0
CC
CC
12 MHz Osc
+ 0.9V
- 0.1V
4
3
VALID
Max
700
V
V
OL
OL
5
- 0.1V
+ 0.1V
4
VALID
10t
2t
12t
CLCL
CLCL
6
Min
Variable Oscillator
0
CLCL
5
VALID
-133
-80
7
6
VALID
10t
SET TI
SET RI
CLCL
Max
8
-133
7
VALID
3053C–MICRO–6/08
Units
ns
μs
ns
ns
ns
IH