diff options
Diffstat (limited to 'libraries/Wire/utility')
| -rw-r--r-- | libraries/Wire/utility/twi.c | 479 | ||||
| -rwxr-xr-x | libraries/Wire/utility/twi.h | 57 |
2 files changed, 0 insertions, 536 deletions
diff --git a/libraries/Wire/utility/twi.c b/libraries/Wire/utility/twi.c deleted file mode 100644 index 2ad2a71..0000000 --- a/libraries/Wire/utility/twi.c +++ /dev/null @@ -1,479 +0,0 @@ -/* - twi.c - TWI/I2C library for Wiring & Arduino - Copyright (c) 2006 Nicholas Zambetti. All right reserved. - - 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 <math.h> -#include <stdlib.h> -#include <inttypes.h> -#include <avr/io.h> -#include <avr/interrupt.h> -#include <compat/twi.h> - -#ifndef cbi -#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit)) -#endif - -#ifndef sbi -#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit)) -#endif - -#include "twi.h" - -static volatile uint8_t twi_state; -static uint8_t twi_slarw; - -static void (*twi_onSlaveTransmit)(void); -static void (*twi_onSlaveReceive)(uint8_t*, int); - -static uint8_t* twi_masterBuffer; -static volatile uint8_t twi_masterBufferIndex; -static uint8_t twi_masterBufferLength; - -static uint8_t* twi_txBuffer; -static volatile uint8_t twi_txBufferIndex; -static volatile uint8_t twi_txBufferLength; - -static uint8_t* twi_rxBuffer; -static volatile uint8_t twi_rxBufferIndex; - -static volatile uint8_t twi_error; - -/* - * Function twi_init - * Desc readys twi pins and sets twi bitrate - * Input none - * Output none - */ -void twi_init(void) -{ - // initialize state - twi_state = TWI_READY; - - #if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__) - // activate internal pull-ups for twi - // as per note from atmega8 manual pg167 - sbi(PORTC, 4); - sbi(PORTC, 5); - #else - // activate internal pull-ups for twi - // as per note from atmega128 manual pg204 - sbi(PORTD, 0); - sbi(PORTD, 1); - #endif - - // initialize twi prescaler and bit rate - cbi(TWSR, TWPS0); - cbi(TWSR, TWPS1); - TWBR = ((CPU_FREQ / TWI_FREQ) - 16) / 2; - - /* twi bit rate formula from atmega128 manual pg 204 - SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR)) - note: TWBR should be 10 or higher for master mode - It is 72 for a 16mhz Wiring board with 100kHz TWI */ - - // enable twi module, acks, and twi interrupt - TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA); - - // allocate buffers - twi_masterBuffer = (uint8_t*) calloc(TWI_BUFFER_LENGTH, sizeof(uint8_t)); - twi_txBuffer = (uint8_t*) calloc(TWI_BUFFER_LENGTH, sizeof(uint8_t)); - twi_rxBuffer = (uint8_t*) calloc(TWI_BUFFER_LENGTH, sizeof(uint8_t)); -} - -/* - * Function twi_slaveInit - * Desc sets slave address and enables interrupt - * Input none - * Output none - */ -void twi_setAddress(uint8_t address) -{ - // set twi slave address (skip over TWGCE bit) - TWAR = address << 1; -} - -/* - * Function twi_readFrom - * Desc attempts to become twi bus master and read a - * series of bytes from a device on the bus - * Input address: 7bit i2c device address - * data: pointer to byte array - * length: number of bytes to read into array - * Output number of bytes read - */ -uint8_t twi_readFrom(uint8_t address, uint8_t* data, uint8_t length) -{ - uint8_t i; - - // ensure data will fit into buffer - if(TWI_BUFFER_LENGTH < length){ - return 0; - } - - // wait until twi is ready, become master receiver - while(TWI_READY != twi_state){ - continue; - } - twi_state = TWI_MRX; - // reset error state (0xFF.. no error occured) - twi_error = 0xFF; - - // initialize buffer iteration vars - twi_masterBufferIndex = 0; - twi_masterBufferLength = length-1; // This is not intuitive, read on... - // On receive, the previously configured ACK/NACK setting is transmitted in - // response to the received byte before the interrupt is signalled. - // Therefor we must actually set NACK when the _next_ to last byte is - // received, causing that NACK to be sent in response to receiving the last - // expected byte of data. - - // build sla+w, slave device address + w bit - twi_slarw = TW_READ; - twi_slarw |= address << 1; - - // send start condition - TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTA); - - // wait for read operation to complete - while(TWI_MRX == twi_state){ - continue; - } - - if (twi_masterBufferIndex < length) - length = twi_masterBufferIndex; - - // copy twi buffer to data - for(i = 0; i < length; ++i){ - data[i] = twi_masterBuffer[i]; - } - - return length; -} - -/* - * Function twi_writeTo - * Desc attempts to become twi bus master and write a - * series of bytes to a device on the bus - * Input address: 7bit i2c device address - * data: pointer to byte array - * length: number of bytes in array - * wait: boolean indicating to wait for write or not - * Output 0 .. success - * 1 .. length to long for buffer - * 2 .. address send, NACK received - * 3 .. data send, NACK received - * 4 .. other twi error (lost bus arbitration, bus error, ..) - */ -uint8_t twi_writeTo(uint8_t address, uint8_t* data, uint8_t length, uint8_t wait) -{ - uint8_t i; - - // ensure data will fit into buffer - if(TWI_BUFFER_LENGTH < length){ - return 1; - } - - // wait until twi is ready, become master transmitter - while(TWI_READY != twi_state){ - continue; - } - twi_state = TWI_MTX; - // reset error state (0xFF.. no error occured) - twi_error = 0xFF; - - // initialize buffer iteration vars - twi_masterBufferIndex = 0; - twi_masterBufferLength = length; - - // copy data to twi buffer - for(i = 0; i < length; ++i){ - twi_masterBuffer[i] = data[i]; - } - - // build sla+w, slave device address + w bit - twi_slarw = TW_WRITE; - twi_slarw |= address << 1; - - // send start condition - TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTA); - - // wait for write operation to complete - while(wait && (TWI_MTX == twi_state)){ - continue; - } - - if (twi_error == 0xFF) - return 0; // success - else if (twi_error == TW_MT_SLA_NACK) - return 2; // error: address send, nack received - else if (twi_error == TW_MT_DATA_NACK) - return 3; // error: data send, nack received - else - return 4; // other twi error -} - -/* - * Function twi_transmit - * Desc fills slave tx buffer with data - * must be called in slave tx event callback - * Input data: pointer to byte array - * length: number of bytes in array - * Output 1 length too long for buffer - * 2 not slave transmitter - * 0 ok - */ -uint8_t twi_transmit(uint8_t* data, uint8_t length) -{ - uint8_t i; - - // ensure data will fit into buffer - if(TWI_BUFFER_LENGTH < length){ - return 1; - } - - // ensure we are currently a slave transmitter - if(TWI_STX != twi_state){ - return 2; - } - - // set length and copy data into tx buffer - twi_txBufferLength = length; - for(i = 0; i < length; ++i){ - twi_txBuffer[i] = data[i]; - } - - return 0; -} - -/* - * Function twi_attachSlaveRxEvent - * Desc sets function called before a slave read operation - * Input function: callback function to use - * Output none - */ -void twi_attachSlaveRxEvent( void (*function)(uint8_t*, int) ) -{ - twi_onSlaveReceive = function; -} - -/* - * Function twi_attachSlaveTxEvent - * Desc sets function called before a slave write operation - * Input function: callback function to use - * Output none - */ -void twi_attachSlaveTxEvent( void (*function)(void) ) -{ - twi_onSlaveTransmit = function; -} - -/* - * Function twi_reply - * Desc sends byte or readys receive line - * Input ack: byte indicating to ack or to nack - * Output none - */ -void twi_reply(uint8_t ack) -{ - // transmit master read ready signal, with or without ack - if(ack){ - TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT) | _BV(TWEA); - }else{ - TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT); - } -} - -/* - * Function twi_stop - * Desc relinquishes bus master status - * Input none - * Output none - */ -void twi_stop(void) -{ - // send stop condition - TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTO); - - // wait for stop condition to be exectued on bus - // TWINT is not set after a stop condition! - while(TWCR & _BV(TWSTO)){ - continue; - } - - // update twi state - twi_state = TWI_READY; -} - -/* - * Function twi_releaseBus - * Desc releases bus control - * Input none - * Output none - */ -void twi_releaseBus(void) -{ - // release bus - TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT); - - // update twi state - twi_state = TWI_READY; -} - -SIGNAL(TWI_vect) -{ - switch(TW_STATUS){ - // All Master - case TW_START: // sent start condition - case TW_REP_START: // sent repeated start condition - // copy device address and r/w bit to output register and ack - TWDR = twi_slarw; - twi_reply(1); - break; - - // Master Transmitter - case TW_MT_SLA_ACK: // slave receiver acked address - case TW_MT_DATA_ACK: // slave receiver acked data - // if there is data to send, send it, otherwise stop - if(twi_masterBufferIndex < twi_masterBufferLength){ - // copy data to output register and ack - TWDR = twi_masterBuffer[twi_masterBufferIndex++]; - twi_reply(1); - }else{ - twi_stop(); - } - break; - case TW_MT_SLA_NACK: // address sent, nack received - twi_error = TW_MT_SLA_NACK; - twi_stop(); - break; - case TW_MT_DATA_NACK: // data sent, nack received - twi_error = TW_MT_DATA_NACK; - twi_stop(); - break; - case TW_MT_ARB_LOST: // lost bus arbitration - twi_error = TW_MT_ARB_LOST; - twi_releaseBus(); - break; - - // Master Receiver - case TW_MR_DATA_ACK: // data received, ack sent - // put byte into buffer - twi_masterBuffer[twi_masterBufferIndex++] = TWDR; - case TW_MR_SLA_ACK: // address sent, ack received - // ack if more bytes are expected, otherwise nack - if(twi_masterBufferIndex < twi_masterBufferLength){ - twi_reply(1); - }else{ - twi_reply(0); - } - break; - case TW_MR_DATA_NACK: // data received, nack sent - // put final byte into buffer - twi_masterBuffer[twi_masterBufferIndex++] = TWDR; - case TW_MR_SLA_NACK: // address sent, nack received - twi_stop(); - break; - // TW_MR_ARB_LOST handled by TW_MT_ARB_LOST case - - // Slave Receiver - case TW_SR_SLA_ACK: // addressed, returned ack - case TW_SR_GCALL_ACK: // addressed generally, returned ack - case TW_SR_ARB_LOST_SLA_ACK: // lost arbitration, returned ack - case TW_SR_ARB_LOST_GCALL_ACK: // lost arbitration, returned ack - // enter slave receiver mode - twi_state = TWI_SRX; - // indicate that rx buffer can be overwritten and ack - twi_rxBufferIndex = 0; - twi_reply(1); - break; - case TW_SR_DATA_ACK: // data received, returned ack - case TW_SR_GCALL_DATA_ACK: // data received generally, returned ack - // if there is still room in the rx buffer - if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){ - // put byte in buffer and ack - twi_rxBuffer[twi_rxBufferIndex++] = TWDR; - twi_reply(1); - }else{ - // otherwise nack - twi_reply(0); - } - break; - case TW_SR_STOP: // stop or repeated start condition received - // put a null char after data if there's room - if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){ - twi_rxBuffer[twi_rxBufferIndex] = '\0'; - } - // callback to user defined callback - twi_onSlaveReceive(twi_rxBuffer, twi_rxBufferIndex); - // ack future responses - twi_reply(1); - // leave slave receiver state - twi_state = TWI_READY; - break; - case TW_SR_DATA_NACK: // data received, returned nack - case TW_SR_GCALL_DATA_NACK: // data received generally, returned nack - // nack back at master - twi_reply(0); - break; - - // Slave Transmitter - case TW_ST_SLA_ACK: // addressed, returned ack - case TW_ST_ARB_LOST_SLA_ACK: // arbitration lost, returned ack - // enter slave transmitter mode - twi_state = TWI_STX; - // ready the tx buffer index for iteration - twi_txBufferIndex = 0; - // set tx buffer length to be zero, to verify if user changes it - twi_txBufferLength = 0; - // request for txBuffer to be filled and length to be set - // note: user must call twi_transmit(bytes, length) to do this - twi_onSlaveTransmit(); - // if they didn't change buffer & length, initialize it - if(0 == twi_txBufferLength){ - twi_txBufferLength = 1; - twi_txBuffer[0] = 0x00; - } - // transmit first byte from buffer, fall - case TW_ST_DATA_ACK: // byte sent, ack returned - // copy data to output register - TWDR = twi_txBuffer[twi_txBufferIndex++]; - // if there is more to send, ack, otherwise nack - if(twi_txBufferIndex < twi_txBufferLength){ - twi_reply(1); - }else{ - twi_reply(0); - } - break; - case TW_ST_DATA_NACK: // received nack, we are done - case TW_ST_LAST_DATA: // received ack, but we are done already! - // ack future responses - twi_reply(1); - // leave slave receiver state - twi_state = TWI_READY; - break; - - // All - case TW_NO_INFO: // no state information - break; - case TW_BUS_ERROR: // bus error, illegal stop/start - twi_error = TW_BUS_ERROR; - twi_stop(); - break; - } -} - diff --git a/libraries/Wire/utility/twi.h b/libraries/Wire/utility/twi.h deleted file mode 100755 index 1258d8d..0000000 --- a/libraries/Wire/utility/twi.h +++ /dev/null @@ -1,57 +0,0 @@ -/* - twi.h - TWI/I2C library for Wiring & Arduino - Copyright (c) 2006 Nicholas Zambetti. All right reserved. - - 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 -*/ - -#ifndef twi_h -#define twi_h - - #include <inttypes.h> - - //#define ATMEGA8 - - #ifndef CPU_FREQ - #define CPU_FREQ 16000000L - #endif - - #ifndef TWI_FREQ - #define TWI_FREQ 100000L - #endif - - #ifndef TWI_BUFFER_LENGTH - #define TWI_BUFFER_LENGTH 32 - #endif - - #define TWI_READY 0 - #define TWI_MRX 1 - #define TWI_MTX 2 - #define TWI_SRX 3 - #define TWI_STX 4 - - void twi_init(void); - void twi_setAddress(uint8_t); - uint8_t twi_readFrom(uint8_t, uint8_t*, uint8_t); - uint8_t twi_writeTo(uint8_t, uint8_t*, uint8_t, uint8_t); - uint8_t twi_transmit(uint8_t*, uint8_t); - void twi_attachSlaveRxEvent( void (*)(uint8_t*, int) ); - void twi_attachSlaveTxEvent( void (*)(void) ); - void twi_reply(uint8_t); - void twi_stop(void); - void twi_releaseBus(void); - -#endif - |