Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.NET

X  

AT89C55WD Datasheet(PDF) 5 Page - ATMEL Corporation

Part # AT89C55WD
Description  8-bit Microcontroller with 20K Bytes Flash
Download  35 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  ATMEL [ATMEL Corporation]
Direct Link  http://www.atmel.com
Logo ATMEL - ATMEL Corporation

AT89C55WD Datasheet(HTML) 5 Page - ATMEL Corporation

  AT89C55WD_05 Datasheet HTML 1Page - ATMEL Corporation AT89C55WD_05 Datasheet HTML 2Page - ATMEL Corporation AT89C55WD_05 Datasheet HTML 3Page - ATMEL Corporation AT89C55WD_05 Datasheet HTML 4Page - ATMEL Corporation AT89C55WD_05 Datasheet HTML 5Page - ATMEL Corporation AT89C55WD_05 Datasheet HTML 6Page - ATMEL Corporation AT89C55WD_05 Datasheet HTML 7Page - ATMEL Corporation AT89C55WD_05 Datasheet HTML 8Page - ATMEL Corporation AT89C55WD_05 Datasheet HTML 9Page - ATMEL Corporation Next Button
Zoom Inzoom in Zoom Outzoom out
 5 / 35 page
background image
5
1921C–MICRO–3/05
AT89C55WD
4.6
Port 3
Port 3 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 3 output buffers can
sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the inter-
nal pull-ups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low
will source current (I
IL) because of the pull-ups.
Port 3 receives some control signals for Flash programming and verification.
Port 3 also serves the functions of various special features of the AT89C55WD, as shown in the
following table.
4.7
RST
Reset input. A high on this pin for two machine cycles while the oscillator is running resets the
device. This pin drives High for 98 oscillator periods after the Watchdog times out. The DISRTO
bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default state of bit
DISRTO, the RESET HIGH out feature is enabled.
4.8
ALE/PROG
Address Latch Enable is an output pulse for latching the low byte of the address during
accesses to external memory. This pin is also the program pulse input (PROG) during Flash
programming.
In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be
used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped dur-
ing each access to external data memory.
If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set,
ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high.
Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.
4.9
PSEN
Program Store Enable is the read strobe to external program memory.
When the AT89C55WD is executing code from external program memory, PSEN is activated
twice each machine cycle, except that two PSEN activations are skipped during each access to
external data memory.
Port Pin
Alternate Functions
P3.0
RXD (serial input port)
P3.1
TXD (serial output port)
P3.2
INT0 (external interrupt 0)
P3.3
INT1 (external interrupt 1)
P3.4
T0 (timer 0 external input)
P3.5
T1 (timer 1 external input)
P3.6
WR (external data memory write strobe)
P3.7
RD (external data memory read strobe)


Similar Part No. - AT89C55WD_05

ManufacturerPart #DatasheetDescription
logo
ATMEL Corporation
AT89C55WD ATMEL-AT89C55WD_02 Datasheet
293Kb / 37P
   8-bit Microcontroller with 20K Bytes Flash
AT89C55WD ATMEL-AT89C55WD_08 Datasheet
522Kb / 35P
   8-bit Microcontroller with 20K Bytes Flash
More results

Similar Description - AT89C55WD_05

ManufacturerPart #DatasheetDescription
logo
ATMEL Corporation
AT89C55 ATMEL-AT89C55 Datasheet
606Kb / 24P
   8-Bit Microcontroller with 20K Bytes Flash
AT89LV55 ATMEL-AT89LV55_06 Datasheet
688Kb / 32P
   8-bit Microcontroller with 20K Bytes Flash
AT89C55WD ATMEL-AT89C55WD_08 Datasheet
522Kb / 35P
   8-bit Microcontroller with 20K Bytes Flash
AT89C55WD ATMEL-AT89C55WD Datasheet
278Kb / 37P
   8-bit Microcontroller with 20K Bytes Flash
AT89LV55 ATMEL-AT89LV55 Datasheet
595Kb / 23P
   8-Bit Microcontroller with 20K Bytes Flash
AT89C55WD ATMEL-AT89C55WD_02 Datasheet
293Kb / 37P
   8-bit Microcontroller with 20K Bytes Flash
AT89LV55 ATMEL-AT89LV55_01 Datasheet
484Kb / 24P
   8-bit Microcontroller with 20K Bytes Flash
AT87F55WD ATMEL-AT87F55WD Datasheet
234Kb / 26P
   8-bit Microcontroller with 20K Bytes QuickFlash?
AT87LV55 ATMEL-AT87LV55 Datasheet
374Kb / 27P
   8-bit Microcontroller with 20K Bytes QuickFlash짰
AT89C52 ATMEL-AT89C52 Datasheet
181Kb / 22P
   8-Bit Microcontroller with 8K Bytes Flash
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com