Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.COM

X  

T89C51AC2-SLSIM Datasheet(PDF) 8 Page - ATMEL Corporation

Part # T89C51AC2-SLSIM
Description  Enhanced 8-bit Microcontroller with 32 KB Flash Memory
Download  117 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  ATMEL [ATMEL Corporation]
Direct Link  http://www.atmel.com
Logo ATMEL - ATMEL Corporation

T89C51AC2-SLSIM Datasheet(HTML) 8 Page - ATMEL Corporation

Back Button T89C51AC2-SLSIM Datasheet HTML 4Page - ATMEL Corporation T89C51AC2-SLSIM Datasheet HTML 5Page - ATMEL Corporation T89C51AC2-SLSIM Datasheet HTML 6Page - ATMEL Corporation T89C51AC2-SLSIM Datasheet HTML 7Page - ATMEL Corporation T89C51AC2-SLSIM Datasheet HTML 8Page - ATMEL Corporation T89C51AC2-SLSIM Datasheet HTML 9Page - ATMEL Corporation T89C51AC2-SLSIM Datasheet HTML 10Page - ATMEL Corporation T89C51AC2-SLSIM Datasheet HTML 11Page - ATMEL Corporation T89C51AC2-SLSIM Datasheet HTML 12Page - ATMEL Corporation Next Button
Zoom Inzoom in Zoom Outzoom out
 8 / 117 page
background image
8
T89C51AC2
4127D–8051–02/03
It is not obvious the last three instructions in this list are Read-Modify-Write instructions.
These instructions read the port (all 8 bits), modify the specifically addressed bit and
write the new byte back to the latch. These Read-Modify-Write instructions are directed
to the latch rather than the pin in order to avoid possible misinterpretation of voltage
(and therefore, logic) levels at the pin. For example, a Port bit used to drive the base of
an external bipolar transistor can not rise above the transistor’s base-emitter junction
voltage (a value lower than VIL). With a logic one written to the bit, attempts by the CPU
to read the Port at the pin are misinterpreted as logic zero. A read of the latch rather
than the pins returns the correct logic-one value.
Quasi-Bidirectional Port
Operation
Port 1, Port 2, Port 3 and Port 4 have fixed internal pull-ups and are referred to as
"quasi-bidirectional" Ports. When configured as an input, the pin impedance appears as
logic one and sources current in response to an external logic zero condition. Port 0 is a
"true bidirectional" pin. The pins float when configured as input. Resets write logic one to
all Port latches. If logical zero is subsequently written to a Port latch, it can be returned
to input conditions by a logical one written to the latch.
Note:
Port latch values change near the end of Read-Modify-Write instruction cycles. Output
buffers (and therefore the pin state) update early in the instruction after Read-Modify-
Write instruction cycle.
Logical zero-to-one transitions in Port 1, Port 2, Port 3 and Port 4 use an additional pull-
up (p1) to aid this logic transition (see Figure 4.). This increases switch speed. This
extra pull-up sources 100 times normal internal circuit current during 2 oscillator clock
periods. The internal pull-ups are field-effect transistors rather than linear resistors. Pull-
ups consist of three p-channel FET (pFET) devices. A pFET is on when the gate senses
logical zero and off when the gate senses logical one. pFET #1 is turned on for two
oscillator periods immediately after a zero-to-one transition in the Port latch. A logical
one at the Port pin turns on pFET #3 (a weak pull-up) through the inverter. This inverter
and pFET pair form a latch to drive logical one. pFET #2 is a very weak pull-up switched
on whenever the associated nFET is switched off. This is traditional CMOS switch con-
vention. Current strengths are 1/10 that of pFET #3.
Table 2. Read-Modify-Write Instructions
Instruction
Description
Example
ANL
logical AND
ANL P1, A
ORL
logical OR
ORL P2, A
XRL
logical EX-OR
XRL P3, A
JBC
jump if bit = 1 and clear bit
JBC P1.1, LABEL
CPL
complement bit
CPL P3.0
INC
increment
INC P2
DEC
decrement
DEC P2
DJNZ
decrement and jump if not zero
DJNZ P3, LABEL
MOV Px.y, C
move carry bit to bit y of Port x
MOV P1.5, C
CLR Px.y
clear bit y of Port x
CLR P2.4
SET Px.y
set bit y of Port x
SET P3.3


Similar Part No. - T89C51AC2-SLSIM

ManufacturerPart #DatasheetDescription
logo
ATMEL Corporation
T89C51AC2-SLSIM ATMEL-T89C51AC2-SLSIM Datasheet
1Mb / 121P
   Enhanced 8-bit Microcontroller with 32 KB Flash Memory
T89C51AC2-SLSIM ATMEL-T89C51AC2-SLSIM Datasheet
1Mb / 121P
   Enhanced 8-bit Microcontroller with 32 KB Flash Memory
More results

Similar Description - T89C51AC2-SLSIM

ManufacturerPart #DatasheetDescription
logo
ATMEL Corporation
AT89C51AC2 ATMEL-AT89C51AC2_06 Datasheet
1Mb / 121P
   Enhanced 8-bit Microcontroller with 32 KB Flash Memory
AT89C51AC2 ATMEL-AT89C51AC2_08 Datasheet
1Mb / 121P
   Enhanced 8-bit Microcontroller with 32 KB Flash Memory
AT89C51AC3 ATMEL-AT89C51AC3_05 Datasheet
1Mb / 143P
   Enhanced 8-bit Microcontroller with 64KB Flash Memory
AT89C51AC3 ATMEL-AT89C51AC3 Datasheet
1Mb / 141P
   Enhanced 8-bit Microcontroller with 64KB Flash Memory
AT89C51AC3 ATMEL-AT89C51AC3_08 Datasheet
1Mb / 140P
   Enhanced 8-bit Microcontroller with 64KB Flash Memory
T89C51CC02_0305 ATMEL-T89C51CC02_0305 Datasheet
1,003Kb / 145P
   Enhanced 8-bit Microcontroller with CAN Controller and Flash Memory
AT89C51CC01 ATMEL-AT89C51CC01 Datasheet
1Mb / 170P
   Enhanced 8-bit Microcontroller with CAN Controller and Flash Memory
T89C51CC01 ATMEL-T89C51CC01_03 Datasheet
1Mb / 160P
   Enhanced 8-bit Microcontroller with CAN Controller and Flash Memory
T89C51CC01 ATMEL-T89C51CC01_08 Datasheet
1Mb / 167P
   Enhanced 8-bit Microcontroller with CAN Controller and Flash Memory
logo
NXP Semiconductors
LPC1102_1106 NXP-LPC1102_1106 Datasheet
301Kb / 39P
   32-bit ARM Cortex-M0 microcontroller; 32 kB flash and 8 kB SRAM
Rev. 4-24 June 2011
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 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100  ...More


Datasheet Download

Go To PDF Page


Link URL




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

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   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