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发表于 2021-2-11 01:09:24
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本帖最后由 lyy-cy 于 2021-2-11 01:11 编辑
库里有，这里的叫 Wire 就是IIC
和arduino一样的用，可以理解为 Ti 定制版的 arduino 里面有个软件的IIC
d:\energia-1.8.10E23\hardware\energia\msp430\libraries\Wire\utility\twi_sw.c
- /*
- ************************************************************************
- * twi_sw.c
- *
- * twi software files for MSP430
- * Copyright (c) 2015 StefanSch. All right reserved.
- *
- * V1.1 : updates to correct SCL and SDA assignments
- * support of connected device scan with return values defined in twi.h
- *
- ***********************************************************************
- This library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
- This library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public
- License along with this library; if not, write to the Free Software
- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- */
- #include "twi_sw.h"
- #include "twi.h"
- #if (DEFAULT_I2C == -1) || defined(LEGACY_I2C) // SW I2C implementation on default or legacy port
- #if (DEFAULT_I2C == -1) && !defined(LEGACY_I2C) /* SW I2C implementation on default and not legacy port */
- #define TWISDAx TWISDA
- #define TWISCLx TWISCL
- #define TWISDAx_SET_MODE TWISDA_SET_MODE
- #define TWISCLx_SET_MODE TWISCL_SET_MODE
- #endif
- #if defined(LEGACY_I2C) && (LEGACY_I2C == -1) /* SW I2C implementation on default and legacy port */
- #define TWISDAx TWISDA1
- #define TWISCLx TWISCL1
- #define TWISDAx_SET_MODE TWISDA1_SET_MODE
- #define TWISCLx_SET_MODE TWISCL1_SET_MODE
- #endif
- #define I2C_DELAY1() __delay_cycles(F_CPU / 1000000UL * 10)
- #define I2C_DELAY2() __delay_cycles(F_CPU / 1000000UL * 20)
- #define I2C_READ BIT0
- #define I2C_WRITE 0
- uint8_t i2c_sw_start(uint8_t address, uint8_t rw);
- uint8_t i2c_sw_txByte(uint8_t data);
- void i2c_sw_ack(void);
- uint8_t i2c_sw_rxByte(uint8_t lastChar);
- void i2c_sw_stop(void);
- void i2c_sw_init(void)
- {
- if (digitalRead(TWISDAx) == 0){ // toggle SCL if SDA is low at startup
- pinMode_int(TWISDAx, TWISDAx_SET_MODE);
- digitalWrite(TWISCLx, LOW);
- pinMode(TWISCLx, OUTPUT);
- pinMode_int(TWISCLx, TWISCLx_SET_MODE);
- }
- pinMode_int(TWISDAx, TWISDAx_SET_MODE);
- pinMode_int(TWISCLx, TWISCLx_SET_MODE);
- }
- uint8_t i2c_sw_read(uint8_t slaveAddress,
- uint16_t numBytes, uint8_t* data, uint8_t sendStop)
- {
- uint16_t i;
- uint8_t ack_error;
-
- ack_error = i2c_sw_start(slaveAddress, I2C_READ); // Send Start condition
- // [ADDR] + R/W bit = 1
- if (ack_error)
- {
- i2c_sw_stop();
- return (ack_error);
- }
- for (i = 0; i < numBytes-1; i++) {
- *data++ = i2c_sw_rxByte(0); // Read data
- }
- *data++ = i2c_sw_rxByte(1); // Read last data
- if (sendStop) i2c_sw_stop(); // Send Stop condition
- return (0);
- }
- uint8_t i2c_sw_write(uint8_t slaveAddress,
- uint16_t numBytes, uint8_t* data, uint8_t sendStop)
- {
- uint16_t i;
- uint8_t status;
-
- status = i2c_sw_start(slaveAddress, I2C_WRITE); // Send Start condition
- // [ADDR] + R/W bit = 0
- if (status) {
- i2c_sw_stop(); // Send Stop condition
- return (TWI_ERROR_ADDR_NACK);
- }
- for (i = 0; i < numBytes; i++) {
- status |= i2c_sw_txByte(*data++); // Send data and ack
- }
- if (sendStop) i2c_sw_stop(); // Send Stop condition
- if (status) return (TWI_ERROR_DATA_NACK);
- return (status);
- }
- uint8_t i2c_sw_start(uint8_t address, uint8_t rw) // Set up start condition for I2C
- {
- digitalWrite(TWISDAx, LOW);
- pinMode(TWISDAx, OUTPUT);
- I2C_DELAY2(); // delay
- digitalWrite(TWISCLx, LOW);
- pinMode(TWISCLx, OUTPUT);
- I2C_DELAY2(); // delay
- return(i2c_sw_txByte((address << 1) | rw)); // [ADDR] + R/W bit
- }
- uint8_t i2c_sw_txByte(uint8_t data)
- {
- uint8_t bits = 0x08;
- uint8_t ack_error;
-
- while (bits != 0x00) // Loop until all bits are shifted
- {
- if (data & BIT7){ // Test data bit
- pinMode(TWISDAx, TWISDAx_SET_MODE);
- }else{
- digitalWrite(TWISDAx, LOW);
- pinMode(TWISDAx, OUTPUT);
- }
- I2C_DELAY2();
- pinMode(TWISCLx, TWISCLx_SET_MODE);
- data <<= 1; // Shift bits 1 place to the left
- I2C_DELAY1(); // Quick delay
- digitalWrite(TWISCLx, LOW);
- pinMode(TWISCLx, OUTPUT);
- bits--; // Loop until 8 bits are sent
- }
- pinMode(TWISDAx, TWISDAx_SET_MODE);
- // Get acknowledge
- I2C_DELAY2();
- pinMode(TWISCLx, TWISCLx_SET_MODE);
- I2C_DELAY2();
- ack_error = digitalRead(TWISDAx);
- digitalWrite(TWISCLx, LOW);
- pinMode(TWISCLx, OUTPUT);
- return (ack_error);
- }
- void i2c_sw_ack(void) // Check for I2C acknowledge
- {
- I2C_DELAY2();
- pinMode(TWISCLx, TWISCLx_SET_MODE);
- I2C_DELAY2();
- digitalWrite(TWISCLx, LOW);
- pinMode(TWISCLx, OUTPUT);
- }
-
- uint8_t i2c_sw_rxByte(uint8_t lastChar) // Read 8 bits of I2C data
- {
- uint8_t bits = 0x08;
- uint8_t data = 0;
- pinMode(TWISDAx, TWISDAx_SET_MODE);
- I2C_DELAY1();
- while (bits > 0) // Loop until all bits are read
- {
- pinMode(TWISCLx, TWISCLx_SET_MODE);
- I2C_DELAY1();
- data <<= 1; // Shift bits 1 place to the left
- if (digitalRead(TWISDAx)) // Check digital input
- data |= 1; // If input is 'H' store a '1'
- digitalWrite(TWISCLx, LOW);
- pinMode(TWISCLx, OUTPUT);
- I2C_DELAY1();
- bits--; // Decrement I2C bit counter
- }
- if (lastChar == 0){
- digitalWrite(TWISDAx, LOW);
- pinMode(TWISDAx, OUTPUT); // Set acknowledge
- }
- I2C_DELAY1();
- pinMode(TWISCLx, TWISCLx_SET_MODE);
- I2C_DELAY1();
- digitalWrite(TWISCLx, LOW);
- pinMode(TWISCLx, OUTPUT);
- I2C_DELAY1();
- return (data); // Return 8-bit data byte
- }
- void i2c_sw_stop(void) // Send I2C stop command
- {
- digitalWrite(TWISDAx, LOW);
- pinMode(TWISDAx, OUTPUT);
- I2C_DELAY2();
- pinMode(TWISCLx, TWISCLx_SET_MODE);
- I2C_DELAY2();
- pinMode(TWISDAx, TWISDAx_SET_MODE);
- I2C_DELAY2();
- }
- #endif // #if (DEFAULT_I2C == -1) || defined(LEGACY_I2C) // SW I2C implementation on default or legacy port
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