Lohe nō ʻoe i nā PCF8574 IC, kahi puʻukū i hiki ke kūʻai ʻokoʻa a kau ʻia paha ma kahi module e like me nā poʻe ʻē aʻe Nā mea uila e kōkua i kāu hoʻohui me kāu papa Arduino. I kēia hihia, he mea hoʻonui o nā mea hoʻokomo a me nā huahana no ke kaʻa ʻōhua I2C.
E noʻonoʻo paha ua loaʻa iā Arduino kāna iho hoʻohui pahi I2C, a he ʻoiaʻiʻo. Akā hiki i ka PCF8574 ke kōkua i ka hoʻolōʻihi ʻana i kēlā bus ma ʻō aku o nā palena o kāu papa hoʻomohala, i hiki ke kōkua nui i kekahi mau mea hana e pono ai ma mua o ka mea i hāʻawi ʻia e Arduino.
He aha ke kaʻa ʻōhua I2C?
Noʻu ka inoa I2C Kaapuni Pākuʻi waena aiʻole nā kaapuni hoʻohui waena. Ua hoʻokumu ʻia kāna mana 1.0 i 1992 e Philips. A laila e hiki mai kahi lua 2.1 i 2000 a i kēia lā ua lilo ia i kūlana (ma 100 kbit / s, ʻoiai e ʻae ʻia a hiki i ka 3.4 Mbit / s ka nui) ke pau ka patent ma 2006 a hiki ke hoʻohana manuahi.
I kēia manawa ua hoʻohana ākea ia i ka ʻoihana no ke kamaʻilio, a mahalo nui ʻia e nā mea hana no kā lākou papahana e kamaʻilio i nā microcontrollers ʻokoʻa a me nā peripherals i hoʻohui ʻia i hoʻokahi IC.
El He kaʻa ʻo I2C kaulana loa mai ke kamaʻilio pūkaʻina. Hoʻohana ia i kahi protocol kamaʻilio pū me nā kahawai 2 wale nō (aia kahi hapakolu, akā hoʻopili ʻia ia i kahi kūmole a i ʻole GND), ʻo ka ʻoiaʻiʻo ua ʻike ʻia ʻo TWI (Two Wire Interface):
- Hoʻokahi no ka uaki (SCL).
- Nā mea ʻē aʻe no ka ʻikepili (SDA).
Hōʻike ia i ka haku a kauā hoʻouna lākou i ka ʻikepili ma luna o ke kaula like a i ʻole ke ala like, i kaohi ʻia e ka mea mua e hana i ka hōʻailona uaki. E loaʻa i kēlā me kēia meahana pili i ka pahi I2C kahi helu ʻokoʻa i hāʻawi ʻia, i mea e kuhikuhi ai i nā lawe. Akā ʻaʻole pono ia he like mau ka haku (multi-master), ʻo ia ka mea nāna i hoʻomaka ka hoʻololi.
E like me kaʻu i wehewehe mua ai i ka ʻatikala ma Arduino I2C Ua kuhikuhi wau ma mua, aia i kēlā me kēia papa kēia mau pilina I2C ma nā wahi like ʻole. He mea ia āu e noʻonoʻo ai e hiki ke hoʻohana pono iā ia i kēlā me kēia mana o ka pā.
- Arduino UNO: Aia ʻo SDA i A4 a me SCK ma A5
- ArduinoNano: like me ka mea i hala.
- ʻO Arduino Mini Pro: like.
- ʻO Arduino Mega: Aia ʻo SDA ma ka pin 20 a me SCK ma ka 21.
- Nā ʻike hou aʻe e pili ana i nā pā.
Maopopo iā ʻoe hiki iā ʻoe ke hoʻohana i ka I2C no kāu sketches maʻalahi, ʻoiai ka Waihona.h hale waihona puke me nā hana like ʻole no kēia kamaʻilio pūkaʻina.
- hoʻomaka (): e hoʻomaka i ka waihona Waihona a kuhikuhi inā he haku a kauā paha ia
- noiFrom (): hoʻohana ʻia e ka haku e noi i ka ʻikepili mai ke kauā.
- hoʻomakaTransmission (): hoʻomaka hoʻoili me ke kauā.
- hoʻouna hope (): hoʻoili hopena.
- kākau ()- Kākau i ka ʻikepili mai kahi kauā e pane i kahi noi mai ka haku, a i ʻole hiki iā ʻoe ke kūlou i ka lawe ʻana o kahi haku.
- loaʻa (): e hoʻihoʻi i ka helu o nā bytes e heluhelu.
- heluhelu(): heluhelu i kahi byte i hoʻoili ʻia mai ke kauā i kahi haku a i ʻole ka hope.
- onReceive (): Kāhea i kahi hana ke loaʻa i kahi kauā kahi lawe mai kahi haku.
- i noi (): Kāhea i kahi hana ke noi ke kauā i ka ʻikepili mai kahi haku.
No ʻike hou aku e pili ana i ka hoʻolālā Arduino a me nā hana hiki iā ʻoe ke hoʻoiho i kā mākou PDF hōʻike aʻo.
He aha ka PCF8574?
ʻO ka PCF8574 a Nā hoʻokomo kikohoʻe I2C pahi a me nā mea hoʻokomo (I / O) expander. Hiki ke hana ʻia e nā mea hana like ʻole, me ka loaʻa iā ia i nā IC a me nā modula. I kēlā me kēia hihia, he kūpono loa e hoʻopili iā ia i kāu papa Arduino a hiki i ka hiki ke kaohi i nā ʻoihana hou aʻe ma mua o ka motherboard i ʻae.
El PCF8574 pinout He maʻalahi ia, ʻoiai e hoʻopili wale 8 pines quasidirectional (P0-P7 kahi e pili ai nā ʻāpana e pili ai), a ma ka ʻaoʻao ʻē aʻe iā ʻoe ka SDA a me SCL e pili pono ʻoe i ka papa Arduino, a ʻo VCC a me GND e hoʻomāhuahua pū i ka modula. A mai poina i nā māka kuhikuhi ʻekolu iā A0, A1, A2 e koho ai i kahi o nā hāmeʻa e kuhikuhi ai ka kamaʻilio i ...
Nāwai nā hiʻohiʻona ʻē aʻe i ʻike ʻoe:
- Kona pili, i ka wehe hamama, hiki ke hoʻohana ʻia ma ke ʻano he hoʻokomo a me ka puka.
- La pihi au ʻo 25mA ke hana ia ma ke ʻano he puka (poho, ke kahe o kēia manawa i PCF8574) a me 300 µA (kumuwaiwai, kahe kahe mai PCF8574).
- La ka pilikia ʻO 2.5 a me 6v ka lako mana. He haʻahaʻa loa ke kū ʻana o ka kū, 10 mau wale nō.
- Nā huahana āpau loaʻa nā latch, e mālama i ka mokuʻāina me ka ʻole o ka hana o waho. Pono ʻoe e hana ke makemake ʻoe e hoʻololi i ka mokuʻāina.
- Hiki iā ʻoe ke loaʻa iā 8 hiki i nā ʻōkuhi, ʻo ia, a i 8 mau hāmeʻa e launa pū me ka hoʻohana ʻana i nā modula 8 e hoʻonui ai a i nā hāmeʻa 64. ʻO nā helu (pin A0, A1, A2) ʻo ia:
- 000: helu wahi 0x20
- 001: helu wahi 0x21
- 010: helu wahi 0x22
- 011: helu wahi 0x23
- 100: helu wahi 0x24
- 101: helu wahi 0x25
- 110: helu wahi 0x26
- 111: helu wahi 0x27
- ʻAe hoʻōki wale (INT) e kahi laina kūikawā e ʻike i ka ʻikepili me ka nānā mau ʻole ʻia.
Hoʻohui pū me Arduino
He mea maʻalahi ka pilina me Arduino, pono ʻoe e hoʻopili iā Vcc me ka pine 5v o ka papa Arduino, a me GND me GND o Arduino. Ma ka lima ʻē aʻe, hiki i nā mākia o ka PCF8574 SDA a me SCL module i hoʻohui me nā pin 14 (A5 SCL) a me 15 (A4 SDA). Me ia wale nō e hoʻomaka ai ka hana, maopopo leʻa hiki iā ʻoe ke hoʻohana i ka Px e hoʻohui i nā hāmeʻa āu e makemake ai e kamaʻilio ...
A laila e nalo wale ana nō ia e hoʻomaka me kahi sketch laʻana i ka Arduino IDE. Hiki iā ʻoe ke hana me ka hoʻohana ʻole ʻana i kahi waihona hou e like me ...
#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);
}
}
As hoʻokomo:
#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);
}
A i ʻole kekahi hoʻohana hale waihona puke, e like me ka PCF8574 i hiki iā ʻoe ʻike maʻaneʻi a hoʻohana i ke code e like me kēia mai ka laʻana ponoʻī e hele pū me kēia waihona:
#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()
{
}