Ngokuqinisekile uzwile ngefayela le- Incazelo: IC PCF8574, i-chip engathengwa ngokuhlukile noma isivele ifakwe kumodyuli njengabanye abaningi Izingxenye ze-elekthronikhi ukwenza lula ukuhlanganiswa kwakho nebhodi lakho le-Arduino. Kulokhu, kungukukhishwa kokufakwayo nemiphumela ye- ibhasi le-I2C.
Ungase ucabange ukuthi i-Arduino isivele inayo eyayo I-I2C ibhasi elihlanganisiwe, futhi kuyiqiniso. Kepha i-PCF8574 ingasiza ukunweba lelo bhasi ngale kwemikhawulo yebhodi lakho lokuthuthuka, elingaba usizo olukhulu kwabanye abenzi abadinga okungaphezu kwalokho okunikezwa yi-Arduino.
Liyini ibhasi le-I2C?
Igama I2C livela ku- Isekethe Ehlanganisiwe noma amasekethe ahlanganisiwe. Inguqulo yayo engu-1.0 yadalwa ngo-1992 nguPhilips. Bese kuthi u-2.1 wesibili afike ngo-2000 futhi namuhla sekuyinto ejwayelekile (ngama-100 kbit / s, yize ivumela kufika ku-3.4 Mbit / s esiphezulu) lapho ilungelo lobunikazi liphela ngo-2006 futhi lingasetshenziswa ngokukhululeka.
Njengamanje isetshenziswa kabanzi embonini yokuxhumana, futhi futhi baziswa kakhulu abenzi bamaphrojekthi abo wokuxhumana ngama-microcontroller ahlukahlukene nemikhawulo ehlanganiswe ku-IC eyodwa.
El I2C ibhasi kwaziwa kahle ngokuxhumana okuyi-serial. Isebenzisa inqubo yokuxhumana ehambisanayo eneziteshi ezi-2 kuphela (kunesithathu, kepha ihlanganiswe nesethenjwa noma i-GND), empeleni yaziwa nangokuthi yi-TWI (Two Wire Interface):
- Eyodwa yewashi (SCL).
- Okunye kwedatha (i-SDA).
Lokho kusho ukuthi inkosi nesigqila bathumela idatha ngentambo efanayo noma ithrekhi, elawulwa eyokuqala eyenza isignali yewashi. Idivayisi ngayinye yomngcele exhunywe ebhasini le-I2C izoba nekheli eliyingqayizivele elinikezwe, ukuqondisa ukuhanjiswa. Kepha akudingekile ukuthi uthisha ahlale efanayo (othisha abaningi), njalo nguye oqala ukudluliswa.
Njengoba ngichazile vele endatshaneni ku I-Arduino I2C Ngikhombisile phambilini, ibhodi ngalinye linokuxhumana kwe-I2C ezindaweni ezahlukahlukene. Kuyinto okufanele uyikhumbule ukuze ukwazi ukuyisebenzisa kahle enguqulweni ngayinye yepuleti:
- Arduino UNO: I-SDA iku-A4 ne-SCK iku-A5
- U-Arduino Nano: kufana nokwedlule.
- I-Arduino Mini Pro: okufanayo.
- I-Arduino Mega: I-SDA iku-pin 20 ne-SCK iku-21.
- Imininingwane engaphezulu ngamacwecwe.
Usuvele uyazi ukuthi ungasebenzisa i-I2C ngemidwebo yakho kalula, ngoba Umtapo wolwazi weWire.h ngemisebenzi eyahlukahlukene yalokhu ukuxhumana okulandelayo:
- qala (): qala umtapo wolwazi we-Wire bese ucacisa uma uyinkosi noma uyisigqila
- isiceloFrom (): kusetshenziswe inkosi ukucela idatha encekwini.
- startTransmission (): qala ukudluliswa ngesigqila.
- EndTransmission (): ukudluliswa kokuphela.
- bhala ()- Bhala idatha kusuka esigqileni uphendule isicelo esivela enkosini, noma ungangena emgqeni wokudluliselwa kwenkosi.
- kuyatholakala (): izobuyisa inani lama-byte azofundwa.
- funda (): funda i-byte edluliselwe isuka esigqileni iye enkosini noma okuphambene nalokho.
- onReceive ()Ibiza umsebenzi lapho isigqila sithola ukudluliswa okuvela enkosini.
- onRequest (): Kubiza umsebenzi lapho isigqila sicela idatha kusuka enkosini.
para ulwazi oluthe xaxa mayelana nohlelo lwe-Arduino nemisebenzi ongayilanda Isifundo se-PDF.
Yini i-PCF8574?
I-PCF8574 iyi- Okokufaka nemiphumela yebhasi ledijithali ye-I2C (I / O) expander. Ingakhiqizwa ngabakhiqizi abahlukahlukene, ngaphezu kokuthi itholakale kuma-IC nakumamojula. Kunoma ikuphi, kuyasiza kakhulu ukuyixhuma ebhodini lakho le-Arduino futhi ube namandla okulawula amadivayisi amaningi kune-motherboard evumayo.
El I-PCF8574 pinout ilula, ngoba ifaka phakathi kuphela Amaphini we-8 i-quasi-directional (P0-P7 lapho ama-chips wokuxhumana axhunyiwe khona), kanti ngakolunye uhlangothi une-SDA ne-SCL okufanele uyixhume ebhodini le-Arduino, kanye ne-VCC ne-GND ukuze uphinde unike amandla imodyuli. Futhi ungakhohlwa izikhonkwane ezintathu zokubhekana no-A0, A1, A2 ukukhetha ukuthi iyiphi ukuxhumana ukuxhumana okuqondiswe ...
Own nezinye izici okufanele wazi:
- Ukuxhumana kwayo, kungaba ngumsele ovulekile, kungaba njalo kusetshenziswe kokubili njengokufakwayo nemiphumela.
- La inani eliphakeme lamanje kungama-25mA lapho isebenza njengokukhiphayo (isinki, lapho okwamanje kugeleza kubheke ku-PCF8574) naku-300 µA (umthombo, ukugeleza kwamanje kusuka ku-PCF8574).
- La Ukushuba kwesimo phakathi ugesi u-2.5 no-6v. Ukusetshenziswa kokuma kuphansi kakhulu, yi-10 onlyA kuphela.
- Yonke imiphumela babe nama-latches, ukugcina umbuso ngaphandle kwesidingo sezenzo zangaphandle. Kufanele wenze kuphela lapho ufuna ukuguqula isimo.
- Ungathola i-8 izinkomba, okungukuthi, kufika kumadivayisi ayi-8 ukuxhumana noma ukusebenzisa amamojula ayi-8 ukuyikhulisa ifinyelela kumadivayisi angama-64. Amakheli (izikhonkwane A0, A1, A2) kuzoba:
- 000: ikheli 0x20
- 001: ikheli 0x21
- 010: ikheli 0x22
- 011: ikheli 0x23
- 100: ikheli 0x24
- 101: ikheli 0x25
- 110: ikheli 0x26
- 111: ikheli 0x27
- Ukuvuma ukuphazamiseka (INT) ngomugqa okhethekile wokuthola idatha ngaphandle kokuqapha njalo.
Ukuhlanganiswa ne-Arduino
Ukuxhumeka ne-Arduino kulula kakhulu, kufanele nje uxhume i-Vcc ngophini we-5v webhodi le-Arduino, ne-GND ne-GND ye-Arduino. Ngakolunye uhlangothi, izikhonkwane ze-PCF8574 SDA ne-SCL module zingaba njalo xhuma ngezikhonkwane 14 (A5 SCL) no-15 (A4 SDA). Ngalokho kuphela kuzoqala ukusebenza, kusobala ukuthi ungasebenzisa i-Px ukuxhuma amadivayisi ofuna ukuxhumana ...
Lapho-ke bekuyobe kulahlekile kuphela qala ngomdwebo wesibonelo ku-Arduino IDE. Ungakwenza ngaphandle kokusebenzisa umtapo wezincwadi owengeziwe njenge ...
#include <Wire.h>
const int address = 0x38;
void setup()
{
Wire.begin();
Serial.begin(9600);
}
void loop()
{
for (short channel = 0; channel < 8; channel++)
{
// Escribir dato en cada uno de los 8 canales
Wire.beginTransmission(address);
Wire.write(~(1 << channel));
Wire.endTransmission();
// Lee dato del canal
delay(500);
}
}
Njengokufaka:
#include <Wire.h>
const int address = 0x38;
void setup()
{
Wire.begin();
Serial.begin(9600);
}
void loop()
{
short channel = 1;
byte value = 0;
// Leer el dato del canal
Wire.requestFrom(pcfAddress, 1 << channel);
if (Wire.available())
{
value = Wire.read();
}
Wire.endTransmission();
// Mostrar el valor leido por el monitor serie
Serial.println(value);
}
Noma futhi sebenzisa imitapo yolwazi, njengePCF8574 ongakwazi landa lapha bese usebenzisa ikhodi efana nalena kusuka esibonelweni uqobo eza nalomtapo wezincwadi:
#include <Wire.h>
#include "PCF8574.h"
PCF8574 expander;
void setup()
{
Serial.begin(9600);
expander.begin(0x20);
/* Setup some PCF8574 pins for demo */
expander.pinMode(0, OUTPUT);
expander.pinMode(1, OUTPUT);
expander.pinMode(2, OUTPUT);
expander.pinMode(3, INPUT_PULLUP);
/* Blink hardware LED for debug */
digitalWrite(13, HIGH);
/* Toggle PCF8574 output 0 for demo */
expander.toggle();
/* Blink hardware LED for debug */
digitalWrite(13, LOW);
}
void loop()
{
}