AT89C55WD-24AI Atmel, AT89C55WD-24AI Datasheet - Page 21
![IC MICRO CTRL 24MHZ 44TQFP](/photos/6/70/67042/313-44-tqfp_sml.jpg)
AT89C55WD-24AI
Manufacturer Part Number
AT89C55WD-24AI
Description
IC MICRO CTRL 24MHZ 44TQFP
Manufacturer
Atmel
Series
89Cr
Datasheet
1.AT89C55WD-24AU.pdf
(35 pages)
Specifications of AT89C55WD-24AI
Core Processor
8051
Core Size
8-Bit
Speed
24MHz
Connectivity
UART/USART
Peripherals
WDT
Number Of I /o
32
Program Memory Size
20KB (20K x 8)
Program Memory Type
FLASH
Ram Size
256 x 8
Voltage - Supply (vcc/vdd)
4.5 V ~ 5.5 V
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
44-TQFP, 44-VQFP
Data Bus Width
8 bit
Data Ram Size
256 B
Maximum Clock Frequency
33 MHz
Number Of Programmable I/os
32
Number Of Timers
3 x 16 bit
Operating Supply Voltage
4 V to 5.5 V
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Eeprom Size
-
Data Converters
-
Lead Free Status / Rohs Status
No RoHS Version Available
Other names
AT89C55WD24AI
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
21. Programming Interface
1921D–MICRO–6/08
Chip Erase Sequence: Before the AT89C55WD can be reprogrammed, a Chip Erase operation
needs to be performed. To erase the contents of the AT89C55WD, follow this sequence:
Data Polling: The AT89C55WD features Data Polling to indicate the end of a write cycle. During
a write cycle, an attempted read of the last byte written will result in the complement of the writ-
ten data on P0.7. Once the write cycle has been completed, true data is valid on all outputs, and
the next cycle may begin. Data Polling may begin any time after a write cycle has been initiated.
Ready/Busy: The progress of byte programming can also be monitored by the RDY/BSY output
signal. P3.0 is pulled low after ALE goes high during programming to indicate BUSY. P3.0 is
pulled high again when programming is done to indicate READY.
Program Verify: If lock bits LB1 and LB2 have not been programmed, the programmed code
data can be read back via the address and data lines for verification. The status of the individual
lock bits can be directly verified by reading them back.
Reading the Signature Bytes: The signature bytes are read by the same procedure as a nor-
mal verification of locations 000H, 100H, and 200H, except that P3.6 and P3.7 must be pulled to
a logic low. The values returned are as follows:
Every code byte in the Flash array can be programmed by using the appropriate combination of
control signals. The write operation cycle is self-timed and once initiated, will automatically time
itself to completion.
Most major worldwide programming vendors offer support for the Atmel AT89 microcontroller
series. Please contact your local programming vendor for the appropriate software revision.
1. Raise V
2. Pulse ALE/PROG once (duration of 200 - 500 ns).
3. Wait for 150 ms.
4. Power V
5. Pulse ALE/PROG once (duration of 200 - 500 ns).
6. Wait for 150 ms.
7. Power V
(000H) = 1EH indicates manufactured by Atmel
(100H) = 55H
(200H) = 06H indicates 89C55WD
CC
CC
CC
to 6.5V.
down and up.
down and up to 6.5V.
AT89C55WD
21