[Hướng dẫn] - Đo nhiệt độ (PIC16F877A - DS18b20-quét led-Giao tiếp máy tính dùng VB2008 )

Forum T ng - iu Khin Vi x l, vi iu khin [Hng dn] o nhit (PIC16F877A - DS18b20-qut led-Giao tip my tnh dng VB2008 )

Thread: o nhit (PIC16F877A - DS18b20-qut led-Giao tip my tnh dng VB2008 )

New Posts Private Messages FAQ Calendar Community Forum Actions Quick Links Advanced Search

Results 1 to 10 of 13 Page 1 of 2 2 Last

o nhit (PIC16F877A - DS18b20-qut led-Giao tip my tnh dng VB2008 )

Bn di l ch l mt v d v thit k giao din m mnh lm,cc bn c th thit k ty .

Join Date:

Location:

Posts:

Thanks:

Thanked 377 Times in 168 Posts

Aug 2009

Ton Duc ThangUniversity

508

294

ict

Super Moderator

[Hng dn] - o nhit (PIC16F877A - DS18b20-qut led-Giao tip m... http://4tech.com.vn/forums/showthread.php/4328-Do-nhiet-do-PIC16F87...

1 trong 9 8/30/2012 9:34 PM

S dng mch ny chuyn USB to COM nh.Gi l 80k

I c im:

Cc c im k thut ca cm bin DS18B20 c th k ra mt cch tm tt nh sau: S dng giao din mt dy nn ch cn c mt chn ra truyn thng. C th o nhit trong khong -55 -> +125 oC.Vi khong nhit l -10C to +85C th chnh xc0.5C.C chc nng cnh bo nhit vc qua gi tr cho trc. in p s dng : 3 5.5 V,c th cu hnh m ha nhiu t 9 12 bit

s bit cng ln th chnh xc cao hn.Thi gian chuyn i nhit ti a l 750ms cho m ha 12 bit Dng tiu th ti ch ngh cc nh. Mi cm bin c mt m nh danh duy nht 64 bit cha trong b nh ROM trn chip (on chip), gi tr nh phnc khc bng tia laze. Nu cu hnh cho DS18B20 theo 9,10,11,12 bit th ta c chnh xc tng ng l : 0.5C , 0.25C ,0.125C,

0.0625C.Theo mc nh ca nh sn xut nu chng ta khng cu hnh ch chuyn i th n s t cu hnh l


2 trong 9 8/30/2012 9:34 PM

12 bit.Khi bt u chuyn i nhit th chn DQ s c ko xung mc thp v khi chuyn i xong th mc

cao.Nh vy ta s cn c vo hin tng ny xc nh khi no chuyn i xong nhit .

II.Lnh ROM

- READ ROM (33h)

Cho php c ra 8 byte m khc bng laser trn ROM, bao gm: 8 bit m nh tn linh kin (10h), 48 bit sxut xng, 8 bit kim tra CRC. Lnh ny ch dng khi trn bus c 1 cm bin DS1820, nu khng s xy ra xungt trn bus do tt c cc thit b t cng p ng.

- MATCH ROM (55h)

Lnh ny c gi i cng vi 64 bit ROM tip theo, cho php b iu khin bus chn ra ch mt cm bin DS1820c th khi trn bus c nhiu cm bin DS1820 cng ni vo. Ch c DS1820 no c 64 bit trn ROM trung khp vi

chui 64 bit va c gi ti mi p ng li cc lnh v b nh tip theo. Cn cc cm bin DS1820 c 64 bitROM khng trng khp s tip tc ch mt xung reset. Lnh ny c s dng c trong trng hp c mt cmbin mt dy, c trong trng hp c nhiu cm bin mt dy.

- SKIP ROM (CCh)

Lnh ny cho php thit b iu khin truy nhp thng n cc lnh b nh ca DS1820 m khng cn gi chuim 64 bit ROM. Nh vy s tit kim c thi gian ch i nhng ch mang hiu qu khi trn b ch c mt cmbin.

- SEARCH ROM (F0h)

Lnh ny cho php b iu khin bus c th d tm c s lng thnh vin t ang c u vo bus v cc gitr c th trong 64 bit ROM ca chng bng mt chu trnh d tm.

- ALARM SEARCH (ECh)

Tin trnh ca lnh ny ging ht nh lnh Search ROM, nhng cm bin DS1820 ch p ng lnh ny khi xuthin iu kin cnh bo trong php o nhit cui cng. iu kin cnh bo y c nh ngha l gi trnhit o c ln hn gi tr TH v nh hn gi tr TL l hai gi tr nhit cao nht v nhit thp nht c t trn thanh ghi trong b nh ca cm bin.

Sau khi thit b ch (thng l mt vi iu khin) s dng cc lnh ROM nh a ch cho cc cm bin mt dyang c u vo bus, thit b ch s a ra cc lnh chc nng DS1820. Bng cc lnh chc nng thit b ch cth c ra v ghi vo b nh nhp (scratchpath) ca cm bin DS1820. khi to qu trnh chuyn i gi tr nhit

o c v xc nh ch cung cp in p ngun. Cc lnh chc nng c th c m t ngn gn nh sau:

- WRITE SCRATCHPAD (4Eh)

Lnh ny cho php ghi 2 byte d liu vo b nh nhp ca DS1820. Byte u tin c ghi vo thanh ghi TH (byte2 ca b nh nhp) cn byte th hai c ghi vo thanh ghi TL (byte 3 ca b nh nhp). D liu truyn theo

trnh t u tin l bit c ngha nht v k tip l nhng bit c ngha gim dn. C hai byte ny phi c ghitrc khi thit b ch xut ra mt xung reset hoc khi c d liu khc xut hin.

- READ SCRATCHPAD (BEh)

Lnh ny cho php thit b ch c ni dung b nh nhp. Qu trnh c bt u t bit c ngha nhy ca byte 0v tip tc cho n byte rh 9 (byte 8 - CRC). Thit b ch c th xut ra mt xung reset lm dng qu trnhc bt k lc no nu nh ch c mt phn ca d liu trn b nh nhp cn c c.

- COPYSCRATCHPAD (48h)

Lnh ny copy ni dung ca hai thanh ghi TH v TL (byte 2 v byte 3) vo b nh EEPROM. Nu cm bin c sdng trong ch d cp ngun l bt u vic o.

- CONVERT T (44h)

Lnh ny khi ng mt qu trnh o v chuyn i gi tr nhit thnh s (nh phn). Sau khi chuyn i gi trkt qu o nhit c lu tr trn thanh ghi nhit 2 byte trong b nh nhp Thi gian chuyn i khng qu200 ms, trong thi gian ang chuyn i nu thc hin lnh c th cc gi tr c ra u bng 0.

- READ POWER SUPPLY (B4h)

Mt lnh c tip sau lnh ny s cho bit DS1820 ang s dng ch cp ngun nh th no, gi tr c cbng 0 nu cp ngun bng chnh ng dn d liu v bng 1 nu cp ngun qua mt ng dn ring.

III.Code dng trong PIC

Code:


3 trong 9 8/30/2012 9:34 PM

#include #use delay(clock=20000000)#fuses HS, NOWDT, NOLVP, NOBROWNOUT, NOPROTECT, NOPUT#use rs232(baud=9600,parity=n,xmit=pin_c6,rcv=pin_c7)#define DS PIN_A3int8 led1,led2;int8 const seg7[10] ={0xC0,0x8F9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90};int8 const char9[10] ={'a','b','c','d','e','f','g','h','j','k'};void reset(){output_low(DS);delay_us( 500 ); output_float(DS); delay_us( 500 ); output_float(DS);}void write(int data){int count;for (count=0; count

2.X l data

Join Date:

Location:

Posts:

Thanks:


Aug 2009

Ton Duc ThangUniversity

508

294

Mail: [email protected]

Reply Reply With QuoteThanks

The Following 4 Users Say Thank You to ict For This Useful Post:

thanh_nam (28-12-2010), traixommoi (02-03-2011), trongtuan_1109 (24-12-2010), tunggee (31-12-2010)

Re: o nhit (PIC16F877A - DS18b20-qut led-Giao tip my tnh dng VB2008 )

anh ICt i,anh c bi vit hay ti liu g v o bit dng atmega+lm335 hin th ra led 7 don ko ,bn emcha hc n PiC nn ko lam c anh ak,

Join Date:

Location:

Posts:

Apr 2010

viettronics

18

2dtk6

Junior Member


5 trong 9 8/30/2012 9:34 PM

Thanks:


2



ngh ict trnh by r hn phn giao tip my tnh dng VB nhe c cha hiu lmJoin Date:Location:

Posts:

Thanks:


Nov 2010

TON DUC THANG

9

0

minhtam20tv

Junior Member



cn ci qu trnh c bit1 v bit 0 ca con DS18B20 sao khng thy trnh by ra vyJoin Date:Location:

Posts:

Thanks:


Nov 2010

TON DUC THANG

9

0

minhtam20tv

Junior Member



c bit y Tm :unsigned read(){

int count, data;for (count=0; count

n y c th dng c cng COM ri , cc thng s cn khai bo th rt r rng ri ng khng,Tip theo l cdata nhn c bng hm serialport1.readExisting. Lu l vi iu khin gi ln 3 byte tng ng vi phnchc,l,n v ca nhit .Sau dng hm MID ly tng phn ra v chuyn sang s .

2.X l data

Mail: [email protected]


The Following User Says Thank You to ict For This Useful Post:

hungsano (29-07-2011)

vudt2412

Junior Member


7 trong 9 8/30/2012 9:34 PM

Post Quick Reply Go Advanced

Previous Thread | Next Thread

Contact Us 4Tech Archive Top


Bn c th ni r hn v d v thit k giao din pha trn c ko?

Join Date:

Location:

Posts:

Thanks:


May2011

PTIT

5

0



em cng quan tm giao din trn nh bc

Join Date:

Location:

Posts:

Thanks:


Apr 2011

sssss

5

0

buonzui

Junior Member

Originally Posted by vudt2412

Bn c th ni r hn v d v thit k giao din pha trn c ko?



bn c code cho 8051 khng vy?Join Date:Location:

Posts:

Thanks:


Feb 2012

ICTU

2

0

kokichi226

Junior Member


Page 1 of 2 2 Last

Quick Navigation Vi x l, vi iu khin Top

There are currently 1 users browsing this thread. (1 members and 0 guests)

thangbnvn

NoneView Tag Cloud Add / Edit Tags

Digg

del.icio.us

StumbleUpon

Google

You may post new threads

You may post replies

You may not post attachments

You may edit your posts

BB code is On

Smilies are On

[IMG] code is On

HTML code is Off

Forum Rules


8 trong 9 8/30/2012 9:34 PM

All times are GMT +7. The time now is 10:36 AM.

Powered by vBulletin Version 4.0.4Copyright 2012 vBulletin Solutions, Inc. All rights reserved.

Copyright 2010 4Tech.Com.Vn. All rights reserved.

Khuyn co s dng cc trnh duyt nh: IE 7+, Firefox 3.6+. phn gii 1024x768.


9 trong 9 8/30/2012 9:34 PM

[Hướng dẫn] - Đo nhiệt độ (PIC16F877A - DS18b20-quét led-Giao tiếp máy tính dùng VB2008 )

Documents