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Файл:Микропроцессорная техника / MSP430G2xx3_Code_Examples / msp430g2xx3_uscib0_i2c_13
.c/* --COPYRIGHT--,BSD_EX
* Copyright (c) 2012, Texas Instruments Incorporated
* All rights reserved.
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* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
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*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
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* its contributors may be used to endorse or promote products derived
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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*******************************************************************************
*
* MSP430 CODE EXAMPLE DISCLAIMER
*
* MSP430 code examples are self-contained low-level programs that typically
* demonstrate a single peripheral function or device feature in a highly
* concise manner. For this the code may rely on the device's power-on default
* register values and settings such as the clock configuration and care must
* be taken when combining code from several examples to avoid potential side
* effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
* for an API functional library-approach to peripheral configuration.
*
* --/COPYRIGHT--*/
//******************************************************************************
// MSP430x22x4 Demo - USCI_B0 I2C Slave RX/TX multiple bytes to MSP430 Master
//
// Description: This demo connects two MSP430's via the I2C bus. The slave
// recieves then transmits to the master. This is the slave code. The interrupt
// driven data transmission is demonstrated using the USCI_B0 TX interrupt.
// ACLK = n/a, MCLK = SMCLK = default DCO = ~1.045Mhz
//
// ***to be used with msp430x22x4_uscib0_i2c_12.c***
//
// /|\ /|\
// MSP430G2xx3 10k 10k MSP430G2xx3
// slave | | master
// ----------------- | | -----------------
// -|XIN P3.1/UCB0SDA|<-|---+->|P3.1/UCB0SDA XIN|-
// | | | | |
// -|XOUT | | | XOUT|-
// | P3.2/UCB0SCL|<-+----->|P3.2/UCB0SCL |
// | | | |
//
// D. Dang
// Texas Instruments Inc.
// February 2011
// Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10
//******************************************************************************
#include <msp430.h>
#define NUM_BYTES 2 // How many bytes?
//**** Please note this value needs to be the same as NUM_BYTES_RX in the
// associated master code. This definition lets the slave know when to
// switch from RX interrupt sources to TX interrupt sources. This is
// important since the interrupt vectors are shared by TX and RX flags.
unsigned char *PTxData; // Pointer to TX data
unsigned char *PRxData; // Pointer to RX data
volatile unsigned char RxBuffer[128]; // Allocate 128 byte of RAM
char SLV_Data = 0x11;
volatile unsigned char TXByteCtr, RXByteCtr, RX = 0;
volatile unsigned char RxBuffer[128]; // Allocate 128 byte of RAM
void USCI_SLAVE_SETUP(void);
void Setup_RX(void);
void Receive(void);
int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
while(1){
USCI_SLAVE_SETUP();
}
}
//------------------------------------------------------------------------------
// The USCI_B0 data ISR is used to move data from MSP430 memory to the
// I2C master. PTxData points to the next byte to be transmitted, and TXByteCtr
// keeps track of the number of bytes transmitted.
//------------------------------------------------------------------------------
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
if(RX == 0){ UCB0TXBUF = SLV_Data++; // Transmit data at address PTxData
TXByteCtr++; // Increment TX byte counter
}
if(RX == 1){*PRxData++ = UCB0RXBUF; // Move RX data to address PRxData
RXByteCtr++; // Increment RX byte count
if(RXByteCtr >= NUM_BYTES){ // Received enough bytes to switch
RX = 0; // to TX?
IE2 &= ~UCB0RXIE;
IE2 |= UCB0TXIE;
RXByteCtr = 0;
}
}
}
//------------------------------------------------------------------------------
// The USCI_B0 state ISR is used to wake up the CPU from LPM0 in order to do
// processing in the main program after data has been transmitted. LPM0 is
// only exit in case of a (re-)start or stop condition when actual data
// was transmitted.
//------------------------------------------------------------------------------
#pragma vector = USCIAB0RX_VECTOR
__interrupt void USCIAB0RX_ISR(void)
{
if(RX == 0){ UCB0STAT &= ~(UCSTPIFG + UCSTTIFG); // Clear interrupt flags
if (TXByteCtr) // Check TX byte counter
__bic_SR_register_on_exit(CPUOFF); // Exit LPM0 if data was
} // transmitted
if(RX == 1){UCB0STAT &= ~(UCSTPIFG + UCSTTIFG); // Clear interrupt flags
}
}
void Setup_RX(void){
_DINT();
RX = 1;
IE2 &= ~UCB0TXIE; // Disable TX interrupt
UCB0CTL1 |= UCSWRST; // Enable SW reset
UCB0CTL0 = UCMODE_3 + UCSYNC; // I2C Slave, synchronous mode
UCB0I2COA = 0x48; // Own Address is 048h
UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
UCB0I2CIE |= UCSTPIE + UCSTTIE; // Enable STT and STP interrupt
IE2 |= UCB0RXIE; // Enable RX interrupt
}
void Receive(void){
PRxData = (unsigned char *)RxBuffer; // Start of RX buffer
RXByteCtr = 0; // Clear RX byte count
TXByteCtr = 0;
__bis_SR_register(CPUOFF + GIE); // Enter LPM0 w/ interrupts
// Remain in LPM0 until master
// finishes TX
}
void USCI_SLAVE_SETUP(void){
P1SEL |= BIT6 + BIT7; // Assign I2C pins to USCI_B0
P1SEL2|= BIT6 + BIT7; // Assign I2C pins to USCI_B0
Setup_RX();
Receive();
}
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