developer85 napisał(a):
Czy ktoś z szanownych kolegów robił może już taką komunikację. Jakieś wskazówki, porady na co zwrócić uwagę.
Z tego co wyczytałem najgorzej będzie zrobić proga dla slave?
Pozdro
Komunikacja mikroprocesorów atmega magistralą sprzętową TWI jest bajecznie łatwa pod warunkiem zastosowania odpowiedniej biblioteki dla atmegi-master i odpowiedniej biblioteki atmegi-slave(może być ich kilka), i tu właśnie przychodzi z pomocą pan Manfred Langemann autor tych bibliotek. Ja tylko dodam, że u mnie komunikacja z atmegami po TWI działa w dwie strony bez problemów - oczywiście dostosowałem(w niewielkim stopniu) te biblioteki od swoich potrzeb. Porty SDA i SCL są ustawiane automatycznie przez sprzętowe TWI. Atmegi zasilam tak jakbym korzystał z ADC. Przy atmega-master port SDA jest podłączony przez rezystor 4,7kOm do plusa zasilania, i port SCL jest podłączony przez rezystor 4,7kOm do plusa zasilania. Przy atmega-slave takich rezystorów niema. Wszystkie porty SDA są połączone ze sobą, wszystkie porty SCL są połączone ze sobą, wszystkie masy procesorów atmega są połączone ze sobą. Korzystam z procesorów Atmega8(docelowo trzy: 1 master i 2 slave) taktowanych "wewnętrznie RC" 8MHz docelowo będą kwarce.
TWI_Slave.h
[syntax=c]/*******************************************************
Author: Manfred Langemann
mailto: Manfred.Langemann ät t-online.de
Begin of project: 04.01.2008
Latest version generated: 04.01.2008
Filename: TWI_Slave.h
Description: TWI slave functions include file
********************************************************/
#ifndef _TWIS
#define _TWIS
#define TWIS_ReadBytes 0x60
#define TWIS_WriteBytes 0xA8
/****************************************************************************
Public Function definitions
****************************************************************************/
uint8_t TWIS_Init (uint8_t Address, uint32_t Bitrate);
void TWIS_Stop (void);
void TWIS_Write (uint8_t byte);
uint8_t TWIS_ReadAck (void);
uint8_t TWIS_ReadNack (void);
uint8_t TWIS_ResonseRequired (uint8_t *TWI_ResonseType);
#endif[/syntax]
TWI_Slave.c
[syntax=c]/*******************************************************
Author: Manfred Langemann
mailto: Manfred.Langemann ät t-online.de
Begin of project: 04.01.2008
Latest version generated: 04.01.2008
Filename: TWI_Slave.c
Description: TWI slave functions
-------------------------------------------------------
Program Example
-------------------------------------------------------
#include "General.h"
#include "TWI_Slave.h"
int main (void)
{
uint8_t i=0;
uint8_t j=0;
uint8_t byte[8];
uint8_t TWIS_ResonseType;
// Clear any interrupt
cli ();
// Wait 0.5 second for POR
Delay_ms (500);
// Initiate the TWI slave interface
TWIS_Init (15, 100000);
// Endless loop
while (1)
{
// Is something to do for the TWI slave interface ?
if (TWIS_ResonseRequired (&TWIS_ResonseType))
{
switch (TWIS_ResonseType)
{
// TWI requests to read a byte from the master.
// It is implicitely assumed, that the master
// sends 8 bytes.
case TWIS_ReadBytes:
for (i=0;i<7;i++)
{
byte[0] = TWIS_ReadAck ();
}
byte[7] = TWIS_ReadNack ();
TWIS_Stop ();
break;
// TWI requests to write a byte to the master.
// It is implicitely assumed, that the master
// is prepared to receive 8 bytes.
case TWIS_WriteBytes:
for (i=0;i<8;i++)
{
TWIS_Write (j++);
}
TWIS_Stop ();
break;
}
}
// Do something else ....... e.g.:
i++;
}
return 0;
}
********************************************************/
#include <stdio.h>
#include <avr/interrupt.h>
#include "General.h"
#include "TWI_Slave.h"
/****************************************************************************
TWI State codes
****************************************************************************/
// General TWI Master staus codes
#define TWI_START 0x08 // START has been transmitted
#define TWI_REP_START 0x10 // Repeated START has been transmitted
#define TWI_ARB_LOST 0x38 // Arbitration lost
// TWI Master Transmitter staus codes
#define TWI_MTX_ADR_ACK 0x18 // SLA+W has been tramsmitted and ACK received
#define TWI_MTX_ADR_NACK 0x20 // SLA+W has been tramsmitted and NACK received
#define TWI_MTX_DATA_ACK 0x28 // Data byte has been tramsmitted and ACK received
#define TWI_MTX_DATA_NACK 0x30 // Data byte has been tramsmitted and NACK received
// TWI Master Receiver staus codes
#define TWI_MRX_ADR_ACK 0x40 // SLA+R has been tramsmitted and ACK received
#define TWI_MRX_ADR_NACK 0x48 // SLA+R has been tramsmitted and NACK received
#define TWI_MRX_DATA_ACK 0x50 // Data byte has been received and ACK tramsmitted
#define TWI_MRX_DATA_NACK 0x58 // Data byte has been received and NACK tramsmitted
// TWI Slave Transmitter staus codes
#define TWI_STX_ADR_ACK 0xA8 // Own SLA+R has been received; ACK has been returned
#define TWI_STX_ADR_ACK_M_ARB_LOST 0xB0 // Arbitration lost in SLA+R/W as Master; own SLA+R has been received; ACK has been returned
#define TWI_STX_DATA_ACK 0xB8 // Data byte in TWDR has been transmitted; ACK has been received
#define TWI_STX_DATA_NACK 0xC0 // Data byte in TWDR has been transmitted; NOT ACK has been received
#define TWI_STX_DATA_ACK_LAST_BYTE 0xC8 // Last data byte in TWDR has been transmitted (TWEA = 0); ACK has been received
// TWI Slave Receiver staus codes
#define TWI_SRX_ADR_ACK 0x60 // Own SLA+W has been received ACK has been returned
#define TWI_SRX_ADR_ACK_M_ARB_LOST 0x68 // Arbitration lost in SLA+R/W as Master; own SLA+W has been received; ACK has been returned
#define TWI_SRX_GEN_ACK 0x70 // General call address has been received; ACK has been returned
#define TWI_SRX_GEN_ACK_M_ARB_LOST 0x78 // Arbitration lost in SLA+R/W as Master; General call address has been received; ACK has been returned
#define TWI_SRX_ADR_DATA_ACK 0x80 // Previously addressed with own SLA+W; data has been received; ACK has been returned
#define TWI_SRX_ADR_DATA_NACK 0x88 // Previously addressed with own SLA+W; data has been received; NOT ACK has been returned
#define TWI_SRX_GEN_DATA_ACK 0x90 // Previously addressed with general call; data has been received; ACK has been returned
#define TWI_SRX_GEN_DATA_NACK 0x98 // Previously addressed with general call; data has been received; NOT ACK has been returned
#define TWI_SRX_STOP_RESTART 0xA0 // A STOP condition or repeated START condition has been received while still addressed as Slave
// TWI Miscellaneous status codes
#define TWI_NO_STATE 0xF8 // No relevant state information available; TWINT = 0
#define TWI_BUS_ERROR 0x00 // Bus error due to an illegal START or STOP condition
/*******************************************************
Public Function: TWIS_Init
Purpose: Initialise the TWI Slave Interface
Input Parameter:
- uint8_t Slave address
- uint32_t TWI_Bitrate (Hz)
Return Value: uint8_t
- FALSE: Bitrate too high
- TRUE: Bitrate OK
*******************************************************/
uint8_t TWIS_Init (uint8_t Address, uint32_t Bitrate)
{
/*
** Set the TWI bitrate
** If TWBR is less 11, then error
*/
TWBR = ((F_CPU/Bitrate)-16)/2;
if (TWBR < 11) return FALSE;
/*
** Set the TWI slave address
*/
TWAR = (Address << 1);
/*
** Activate TWI interface
*/
TWCR = (1<<TWEN)|(1<<TWEA);
return TRUE;
}
/*******************************************************
Public Function: TWIS_Stop
Purpose: Stop the TWI Slave Interface
Input Parameter: None
Return Value: None
*******************************************************/
void TWIS_Stop (void)
{
TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO)|(1<<TWEA);
}
/*******************************************************
Public Function: TWIS_Write
Purpose: Write a byte to the master
Input Parameter:
- uint8_t Byte to be sent
Return Value: uint8_t
- TRUE: OK, Byte sent
- FALSE: Error in byte transmission
*******************************************************/
void TWIS_Write (uint8_t byte)
{
TWDR = byte;
TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWEA);
while (!(TWCR & (1<<TWINT)));
}
/*******************************************************
Public Function: TWIS_ReadAck
Purpose: Read a byte from the master and request next byte
Input Parameter: None
Return Value: uint8_t
- uint8_t Read byte
*******************************************************/
uint8_t TWIS_ReadAck (void)
{
TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWEA);
while (!(TWCR & (1<<TWINT)));
return TWDR;
}
/*******************************************************
Public Function: TWIS_ReadNack
Purpose: Read the last byte from the master
Input Parameter: None
Return Value: uint8_t
- uint8_t Read byte
*******************************************************/
uint8_t TWIS_ReadNack (void)
{
TWCR = (1<<TWINT)|(1<<TWEN);
while (!(TWCR & (1<<TWINT)));
return TWDR;
}
/*******************************************************
Public Function: TWIS_ResonseRequired
Purpose: Get the response type to be performed by slave
Input Parameter:
- uint8_t* Pointer to response type
on return:
TWIS_ReadBytes --> Read byte(s) from master
TWIS_WriteBytes --> Write byte(s) to master
Return Value: uint8_t
Response required
TRUE: Yes, response required
FALSE: No response required
*******************************************************/
uint8_t TWIS_ResonseRequired (uint8_t *TWI_ResonseType)
{
*TWI_ResonseType = TWSR;
return TWCR & (1<<TWINT);
}
[/syntax]
TWI_Master.h
[syntax=c]/*******************************************************
Author: Manfred Langemann
mailto: Manfred.Langemann ät t-online.de
Begin of project: 04.01.2008
Latest version generated: 04.01.2008
Filename: TWI_Master.h
Description: TWI Master functions include file
********************************************************/
#ifndef _TWIM
#define _TWIM
#define TWIM_READ 1
#define TWIM_WRITE 0
uint8_tTWIM_Init (uint32_t TWI_Bitrate);
uint8_t TWIM_Start (uint8_t address, uint8_t TWIM_Type);
voidTWIM_Stop (void);
uint8_tTWIM_Write (uint8_t byte);
uint8_tTWIM_ReadAck (void);
uint8_tTWIM_ReadNack (void);
#endif[/syntax]
TWI_Master.c
[syntax=c]/*******************************************************
Author: Manfred Langemann
mailto: Manfred.Langemann ät t-online.de
Begin of project: 04.01.2008
Latest version generated: 04.01.2008
Filename: TWI_Master.c
Description: TWI Master functions
Master code adapted form Peter Fleury <pfleury@gmx.ch>
http://jump.to/fleury
--------------------------------------------------------
Program Example
--------------------------------------------------------
int main (void)
{
uint8_t i=0;
uint8_t j=0;
uint8_t Data[8];
uint8_t SlaveAddress = 15;
// Clear any interrupt
cli ();
// Wait 1 second for POR
Delay_ms (1000);
// Initiate RS232
RS232_Init ();
printf ("Hello world...\n");
// Initiate TWI Master with bitrate of 100000 Hz
TWIM_Init (100000);
// Endless loop
while (1)
{
// Read byte(s) from the slave.
// It is implicitely assumed, that the slave will send
// 8 bytes.
if (!TWIM_Start (SlaveAddress, TWIM_READ))
{
TWIM_Stop ();
printf ("Could not start TWI Bus for READ\n");
}
else
{
for (i=0;i<7;i++)
{
Data[i] = TWIM_ReadAck ();
}
Data[7] = TWIM_ReadNack ();
printf ("Reading Byte %d: %d\n", i, Data[i]);
TWIM_Stop ();
Delay_ms (1000);
}
// Write byte(s) to the slave.
// It is implicitely assumed, that the slave will
// accepts 8 bytes
if (!TWIM_Start (SlaveAddress, TWIM_WRITE))
{
TWIM_Stop ();
printf ("Could not start TWI Bus for WRITE\n");
}
else
{
for (i=0;i<8;i++)
{
TWIM_Write (j++);
printf ("Byte %d sent\n", j);
}
TWIM_Stop ();
Delay_ms (1000);
}
// Do something else
i++;
}
return 0;
}
********************************************************/
#include <stdio.h>
#include <avr/interrupt.h>
#include "General.h"
#include "TWI_Master.h"
/****************************************************************************
TWI State codes
****************************************************************************/
// General TWI Master staus codes
#define TWI_START 0x08 // START has been transmitted
#define TWI_REP_START 0x10 // Repeated START has been transmitted
#define TWI_ARB_LOST 0x38 // Arbitration lost
// TWI Master Transmitter staus codes
#define TWI_MTX_ADR_ACK 0x18 // SLA+W has been tramsmitted and ACK received
#define TWI_MTX_ADR_NACK 0x20 // SLA+W has been tramsmitted and NACK received
#define TWI_MTX_DATA_ACK 0x28 // Data byte has been tramsmitted and ACK received
#define TWI_MTX_DATA_NACK 0x30 // Data byte has been tramsmitted and NACK received
// TWI Master Receiver staus codes
#define TWI_MRX_ADR_ACK 0x40 // SLA+R has been tramsmitted and ACK received
#define TWI_MRX_ADR_NACK 0x48 // SLA+R has been tramsmitted and NACK received
#define TWI_MRX_DATA_ACK 0x50 // Data byte has been received and ACK tramsmitted
#define TWI_MRX_DATA_NACK 0x58 // Data byte has been received and NACK tramsmitted
// TWI Slave Transmitter staus codes
#define TWI_STX_ADR_ACK 0xA8 // Own SLA+R has been received; ACK has been returned
#define TWI_STX_ADR_ACK_M_ARB_LOST 0xB0 // Arbitration lost in SLA+R/W as Master; own SLA+R has been received; ACK has been returned
#define TWI_STX_DATA_ACK 0xB8 // Data byte in TWDR has been transmitted; ACK has been received
#define TWI_STX_DATA_NACK 0xC0 // Data byte in TWDR has been transmitted; NOT ACK has been received
#define TWI_STX_DATA_ACK_LAST_BYTE 0xC8 // Last data byte in TWDR has been transmitted (TWEA = “0”); ACK has been received
// TWI Slave Receiver staus codes
#define TWI_SRX_ADR_ACK 0x60 // Own SLA+W has been received ACK has been returned
#define TWI_SRX_ADR_ACK_M_ARB_LOST 0x68 // Arbitration lost in SLA+R/W as Master; own SLA+W has been received; ACK has been returned
#define TWI_SRX_GEN_ACK 0x70 // General call address has been received; ACK has been returned
#define TWI_SRX_GEN_ACK_M_ARB_LOST 0x78 // Arbitration lost in SLA+R/W as Master; General call address has been received; ACK has been returned
#define TWI_SRX_ADR_DATA_ACK 0x80 // Previously addressed with own SLA+W; data has been received; ACK has been returned
#define TWI_SRX_ADR_DATA_NACK 0x88 // Previously addressed with own SLA+W; data has been received; NOT ACK has been returned
#define TWI_SRX_GEN_DATA_ACK 0x90 // Previously addressed with general call; data has been received; ACK has been returned
#define TWI_SRX_GEN_DATA_NACK 0x98 // Previously addressed with general call; data has been received; NOT ACK has been returned
#define TWI_SRX_STOP_RESTART 0xA0 // A STOP condition or repeated START condition has been received while still addressed as Slave
// TWI Miscellaneous status codes
#define TWI_NO_STATE 0xF8 // No relevant state information available; TWINT = “0”
#define TWI_BUS_ERROR 0x00 // Bus error due to an illegal START or STOP condition
/*******************************************************
Public Function: TWIM_Init
Purpose: Initialise the TWI Master Interface
Input Parameter:
- uint16_t TWI_Bitrate (Hz)
Return Value: uint8_t
- FALSE: Bitrate too high
- TRUE: Bitrate OK
*******************************************************/
uint8_t TWIM_Init (uint32_t TWI_Bitrate)
{
/*
** Set TWI bitrate
** If bitrate is too high, then error return
*/
TWBR=11;
// TWBR = ((F_CPU/TWI_Bitrate)-16)/2;
// if (TWBR < 11) return FALSE;
return TRUE;
}
/*******************************************************
Public Function: TWIM_Start
Purpose: Start the TWI Master Interface
Input Parameter:
- uint8_t Device address
- uint8_t Type of required Operation:
TWIM_READ: Read data from the slave
TWIM_WRITE: Write data to the slave
Return Value: uint8_t
- TRUE: OK, TWI Master accessible
- FALSE: Error in starting TWI Master
*******************************************************/
uint8_t TWIM_Start (uint8_t Address, uint8_t TWIM_Type)
{
uint8_ttwst;
/*
** Send START condition
*/
TWCR = (1<<TWINT)|(1<<TWSTA)|(1<<TWEN);
/*
** Wait until transmission completed
*/
while (!(TWCR & (1<<TWINT)));
/*
** Check value of TWI Status Register. Mask prescaler bits.
*/
twst = TWSR & 0xF8;
if ((twst != TWI_START) && (twst != TWI_REP_START)) return FALSE;
/*
** Send device address
*/
TWDR = (Address<<1) + TWIM_Type;
TWCR = (1<<TWINT)|(1<<TWEN);
/*
** Wait until transmission completed and ACK/NACK has been received
*/
while (!(TWCR & (1<<TWINT)));
/*
** Check value of TWI Status Register. Mask prescaler bits.
*/
twst = TWSR & 0xF8;
if ((twst != TWI_MTX_ADR_ACK) && (twst != TWI_MRX_ADR_ACK)) return FALSE;
return TRUE;
}
/*******************************************************
Public Function: TWIM_Stop
Purpose: Stop the TWI Master
Input Parameter: None
Return Value: None
*******************************************************/
void TWIM_Stop (void)
{
/*
** Send stop condition
*/
TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
/*
** Wait until stop condition is executed and bus released
*/
while (TWCR & (1<<TWINT));
}
/*******************************************************
Public Function: TWIM_Write
Purpose: Write a byte to the slave
Input Parameter:
- uint8_t Byte to be sent
Return Value: uint8_t
- TRUE: OK, Byte sent
- FALSE: Error in byte transmission
*******************************************************/
uint8_t TWIM_Write (uint8_t byte)
{
uint8_t twst;
/*
** Send data to the previously addressed device
*/
TWDR = byte;
TWCR = (1<<TWINT)|(1<<TWEN);
/*
** Wait until transmission completed
*/
while (!(TWCR & (1<<TWINT)));
/*
** Check value of TWI Status Register. Mask prescaler bits
*/
twst = TWSR & 0xF8;
if (twst != TWI_MTX_DATA_ACK) return 1;
return 0;
}
/*******************************************************
Public Function: TWIM_ReadAck
Purpose: Read a byte from the slave and request next byte
Input Parameter: None
Return Value: uint8_t
- uint8_t Read byte
*******************************************************/
uint8_t TWIM_ReadAck (void)
{
TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWEA);
while (!(TWCR & (1<<TWINT)));
return TWDR;
}
/*******************************************************
Public Function: TWIM_ReadAck
Purpose: Read the last byte from the slave
Input Parameter: None
Return Value: uint8_t
- uint8_t Read byte
*******************************************************/
uint8_t TWIM_ReadNack (void)
{
TWCR = (1<<TWINT)|(1<<TWEN);
while(!(TWCR & (1<<TWINT)));
return TWDR;
}[/syntax]
General.h
[syntax=c]#ifndef _General
#define _General
#define TRUE 1
#define FALSE 0
/*
** Here are some deinitions, used in all programs
*/
#define SYSCLOCK 8000000 // Quarz Frequenz in Hz
#define SET_BIT(PORT, BITNUM) ((PORT) |= (1<<(BITNUM)))
#define CLEAR_BIT(PORT, BITNUM) ((PORT) &= ~(1<<(BITNUM)))
#define TOOGLE_BIT(PORT,BITNUM) ((PORT) ^= (1<<(BITNUM)))
struct BitsOfByte
{
uint8_t b0:1;
uint8_t b1:1;
uint8_t b2:1;
uint8_t b3:1;
uint8_t b4:1;
uint8_t b5:1;
uint8_t b6:1;
uint8_t b7:1;
} __attribute__((__packed__));
#define SBIT(port,pin) ((*(volatile struct BitsOfByte*)&port).b##pin)
#endif
[/syntax]
Przykłady jak zastosować biblioteki w swoich programach zamieszczone sa w plikach *.c przez ich autora, więc nie powinno być kłopotów z dostosowaniem do swoich potrzeb.
Mam nadzieje, że pan Mirek kiedyś o sprzetowej magistrali TWI zrobi poradnik video.
PiotrStatystyki: Napisane przez p_zag — 4 sty 2013, o 21:12
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cieszę się i dlatego myślę, że dalej już wszystko będzie dobrze.