+++ /dev/null
-/*!
- * \file
- * <!--
- * Copyright 2003, 2004 Develer S.r.l. (http://www.develer.com/)
- * All Rights Reserved.
- * -->
- *
- * \version $Id$
- *
- * \author Stefano Fedrigo <aleph@develer.com>
- *
- * \brief I2C eeprom driver
- *
- * \note This implementation is AVR specific.
- */
-
-/*
- * $Log$
- * Revision 1.2 2004/07/22 01:24:43 bernie
- * Document AVR dependency.
- *
- * Revision 1.1 2004/07/20 17:11:18 bernie
- * Import into DevLib.
- *
- */
-
-#include "eeprom.h"
-#include <mware/byteorder.h> /* cpu_to_be16() */
-#include <drv/kdebug.h>
-#include <hw.h>
-
-#include <avr/twi.h>
-
-
-/* Wait for TWINT flag set: bus is ready */
-#define WAIT_TWI_READY do {} while (!(TWCR & BV(TWINT)))
-
-/*! \name EEPROM control codes */
-/*@{*/
-#define SLA_W 0xA0
-#define SLA_R 0xA1
-/*@}*/
-
-
-/*!
- * Send START condition on the bus.
- *
- * \return true on success, false otherwise.
- */
-static bool twi_start(void)
-{
- TWCR = BV(TWINT) | BV(TWSTA) | BV(TWEN);
- WAIT_TWI_READY;
-
- if (TW_STATUS == TW_START || TW_STATUS == TW_REP_START)
- return true;
-
- DB(kprintf("!TW_(REP)START: %x\n", TWSR);)
- return false;
-}
-
-
-/*!
- * Send START condition and select slave for write.
- *
- * \return true on success, false otherwise.
- */
-static bool twi_start_w(uint8_t slave_addr)
-{
- //TRACE;
-
- /* Do a loop on the select write sequence because if the
- * eeprom is busy writing precedently sent data it will respond
- * with NACK to the SLA_W control byte. In this case we have
- * to try until the eeprom reply with an ACK.
- */
- while (twi_start())
- {
- TWDR = SLA_W | ((slave_addr & 0x5) << 1);
- TWCR = BV(TWINT) | BV(TWEN);
- WAIT_TWI_READY;
-
- if (TW_STATUS == TW_MT_SLA_ACK)
- return true;
- else if (TW_STATUS != TW_MT_SLA_NACK)
- {
- DB(kprintf("!TW_MT_SLA_(N)ACK: %x\n", TWSR);)
- break;
- }
- }
-
- return false;
-}
-
-
-/*!
- * Send START condition and select slave for read.
- *
- * \return true on success, false otherwise.
- */
-static bool twi_start_r(uint8_t slave_addr)
-{
- //TRACE;
-
- if (twi_start())
- {
- TWDR = SLA_R | ((slave_addr & 0x5) << 1);
- TWCR = BV(TWINT) | BV(TWEN);
- WAIT_TWI_READY;
-
- if (TW_STATUS == TW_MR_SLA_ACK)
- return true;
-
- DB(kprintf("!TW_MR_SLA_ACK: %x\n", TWSR);)
- }
-
- return false;
-}
-
-
-/*!
- * Send STOP condition.
- */
-static void twi_stop(void)
-{
- //TRACE;
-
- TWCR = BV(TWINT) | BV(TWEN) | BV(TWSTO);
-}
-
-
-/*!
- * Send a sequence of bytes in master transmitter mode
- * to the selected slave device through the TWI bus.
- *
- * \return true on success, false on error.
- */
-static bool twi_send(const uint8_t *buf, size_t count)
-{
- //TRACE;
-
- while (count--)
- {
- TWDR = *buf++;
- TWCR = BV(TWINT) | BV(TWEN);
- WAIT_TWI_READY;
- if (TW_STATUS != TW_MT_DATA_ACK)
- {
- DB(kprintf("!TW_MT_DATA_ACK: %x\n", TWSR);)
- return false;
- }
- }
-
- return true;
-}
-
-
-/*!
- * Receive a sequence of one or more bytes from the
- * selected slave device in master receive mode through
- * the TWI bus.
- *
- * Received data is placed in \c buf.
- *
- * \return true on success, false on error
- */
-static bool twi_recv(uint8_t *buf, size_t count)
-{
- //TRACE;
-
- /*
- * When reading the last byte the TWEA bit is not
- * set, and the eeprom should answer with NACK
- */
- while (count--)
- {
- TWCR = BV(TWINT) | BV(TWEN) | (count ? BV(TWEA) : 0);
- WAIT_TWI_READY;
-
- if (count)
- {
- if (TW_STATUS != TW_MR_DATA_ACK)
- {
- DB(kprintf("!TW_MR_DATA_ACK: %x\n", TWSR);)
- return false;
- }
- }
- else
- {
- if (TW_STATUS != TW_MR_DATA_NACK)
- {
- DB(kprintf("!TW_MR_DATA_NACK: %x\n", TWSR);)
- return false;
- }
- }
- *buf++ = TWDR;
- }
-
- return true;
-}
-
-
-/*!
- * Copy \c count bytes from buffer \c buf to
- * eeprom at address \c addr.
- *
- * \note No check is done for data crossing page
- * boundaries.
- */
-bool eeprom_write(e2addr_t addr, const void *buf, size_t count)
-{
- // eeprom accepts address as big endian
- addr = cpu_to_be16(addr);
-
- bool res =
- twi_start_w(0)
- && twi_send((uint8_t *)&addr, sizeof(addr))
- && twi_send(buf, count);
-
- twi_stop();
-
- return res;
-}
-
-
-/*!
- * Copy \c count bytes at address \c addr
- * from eeprom to RAM to buffer \c buf.
- */
-bool eeprom_read(e2addr_t addr, void *buf, size_t count)
-{
- // eeprom accepts address as big endian
- addr = cpu_to_be16(addr);
-
- bool res =
- twi_start_w(0)
- && twi_send((uint8_t *)&addr, sizeof(addr))
- && twi_start_r(0)
- && twi_recv(buf, count);
-
- twi_stop();
-
- return res;
-}
-
-
-/*!
- * Write a single character \a c at address \a addr.
- */
-bool eeprom_write_char(e2addr_t addr, char c)
-{
- return eeprom_write(addr, &c, 1);
-}
-
-
-/*!
- * Read a single character at address \a addr.
- *
- * \return the requested character or -1 in case of failure.
- */
-int eeprom_read_char(e2addr_t addr)
-{
- char c;
-
- if (eeprom_read(addr, &c, 1))
- return c;
- else
- return -1;
-}
-
-
-/*!
- * Initialize TWI module.
- */
-void eeprom_init(void)
-{
- cpuflags_t flags;
- DISABLE_IRQSAVE(flags);
-
- DDRD |= BV(PORTD0) | BV(PORTD1);
- PORTD |= BV(PORTD0) | BV(PORTD1);
-
- /*
- * Set speed:
- * F = CLOCK_FREQ / (16 + 2*TWBR * 4^TWPS)
- */
-# define TWI_FREQ 300000 /* 300 kHz */
-# define TWI_PRESC 1 /* 4 ^ TWPS */
-
- TWBR = (CLOCK_FREQ / (2 * TWI_FREQ * TWI_PRESC)) - (8 / TWI_PRESC);
- TWSR = 0;
-
- ENABLE_IRQRESTORE(flags);
-}
-
-
-#ifdef _DEBUG
-
-void eeprom_test(void)
-{
- static const char magic[] = "Humpty Dumpty";
- char buf[sizeof magic];
-
- // Write something to EEPROM and read it back
- eeprom_write(0, magic, sizeof magic);
- eeprom_read(0, buf, sizeof buf);
- kprintf("EEPROM read: %s\n", buf);
-}
-
-#endif // _DEBUG
-
projects / bertos.git / blobdiff