X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=drv%2Ftwi.c;h=d0c6537428369569fd50cea491eeaf89dbf719ac;hb=7920ccf2c9be523f680d88ef7d681d09af7da209;hp=fa3f094b4960554e821cfbb832facc6fa906be0c;hpb=9a544e24ba666ff6783c0c83f9e77f0b27e474cd;p=bertos.git diff --git a/drv/twi.c b/drv/twi.c index fa3f094b..d0c65374 100755 --- a/drv/twi.c +++ b/drv/twi.c @@ -1,8 +1,8 @@ -/*! +/** * \file * * * \brief Driver for the AVR ATMega TWI (implementation) @@ -15,6 +15,21 @@ /*#* *#* $Log$ + *#* Revision 1.7 2006/07/19 12:56:26 bernie + *#* Convert to new Doxygen style. + *#* + *#* Revision 1.6 2006/03/20 17:49:50 bernie + *#* Make the TWI driver more generic to work with devices other than EEPROMS. + *#* + *#* Revision 1.5 2005/11/27 23:33:40 bernie + *#* Use appconfig.h instead of cfg/config.h. + *#* + *#* Revision 1.4 2005/04/11 19:10:28 bernie + *#* Include top-level headers from cfg/ subdir. + *#* + *#* Revision 1.3 2005/03/01 23:26:00 bernie + *#* Header fix. + *#* *#* Revision 1.2 2005/01/25 08:36:56 bernie *#* CONFIG_TWI_FREQ: New config param. *#* @@ -24,26 +39,23 @@ *#*/ #include "twi.h" -#include "config.h" -#include + +#include +#include +#include // BV() #include -#include -#include // BV() +#include -#include +#include /* 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 -/*@}*/ +#define READ_BIT BV(0) -/*! +/** * Send START condition on the bus. * * \return true on success, false otherwise. @@ -61,15 +73,15 @@ static bool twi_start(void) } -/*! +/** * Send START condition and select slave for write. + * \c id is the device id comprehensive of address left shifted by 1. + * The LSB of \c id is ignored and reset to 0 for write operation. * * \return true on success, false otherwise. */ -bool twi_start_w(uint8_t slave_addr) +bool twi_start_w(uint8_t id) { - ASSERT(slave_addr < 8); - /* * Loop on the select write sequence: when the eeprom is busy * writing previously sent data it will reply to the SLA_W @@ -78,7 +90,7 @@ bool twi_start_w(uint8_t slave_addr) */ while (twi_start()) { - TWDR = SLA_W | (slave_addr << 1); + TWDR = id & ~READ_BIT; TWCR = BV(TWINT) | BV(TWEN); WAIT_TWI_READY; @@ -95,18 +107,18 @@ bool twi_start_w(uint8_t slave_addr) } -/*! +/** * Send START condition and select slave for read. + * \c id is the device id comprehensive of address left shifted by 1. + * The LSB of \c id is ignored and set to 1 for read operation. * * \return true on success, false otherwise. */ -bool twi_start_r(uint8_t slave_addr) +bool twi_start_r(uint8_t id) { - ASSERT(slave_addr < 8); - if (twi_start()) { - TWDR = SLA_R | (slave_addr << 1); + TWDR = id | READ_BIT; TWCR = BV(TWINT) | BV(TWEN); WAIT_TWI_READY; @@ -120,16 +132,36 @@ bool twi_start_r(uint8_t slave_addr) } -/*! +/** * Send STOP condition. */ void twi_stop(void) { - TWCR = BV(TWINT) | BV(TWEN) | BV(TWSTO); + TWCR = BV(TWINT) | BV(TWEN) | BV(TWSTO); } -/*! +/** + * Put a single byte in master transmitter mode + * to the selected slave device through the TWI bus. + * + * \return true on success, false on error. + */ +bool twi_put(const uint8_t data) +{ + TWDR = data; + TWCR = BV(TWINT) | BV(TWEN); + WAIT_TWI_READY; + if (TW_STATUS != TW_MT_DATA_ACK) + { + kprintf("!TW_MT_DATA_ACK: %x\n", TWSR); + return false; + } + return true; +} + + +/** * Send a sequence of bytes in master transmitter mode * to the selected slave device through the TWI bus. * @@ -141,21 +173,14 @@ bool twi_send(const void *_buf, size_t count) while (count--) { - TWDR = *buf++; - TWCR = BV(TWINT) | BV(TWEN); - WAIT_TWI_READY; - if (TW_STATUS != TW_MT_DATA_ACK) - { - kprintf("!TW_MT_DATA_ACK: %x\n", TWSR); + if (!twi_put(*buf++)) 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. @@ -200,7 +225,7 @@ bool twi_recv(void *_buf, size_t count) } -/*! +/** * Initialize TWI module. */ void twi_init(void)