v1.2: No internal address transmission when reading/writing to next internal address (auto-increment feature of most I2C devices)

Doxyfile

@@ -38,7 +38,7 @@ PROJECT_NAME           = "Arduino Hardware I2C for AVR MCUs (plain c)"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 1.1
+PROJECT_NUMBER         = 1.2
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a

Release Notes.txt

@@ -15,6 +15,9 @@ Feel free to share your thoughts @ xgarmanboziax@gmail.com about:
 ------------
 
 ** Actual:
+v1.2	30 Nov 2017:
+- No internal address transmission when reading/writing to next internal address (make sure not to r/w last 16 address right just after init, otherwise make a dummy of address 0 just before)
+
 v1.1	29 Nov 2017:
 - Frequency calculation fix (thanks to TonyWilk)
 - Set Frequency higher than Fast Mode (400KHz) will set bus to Fast Mode (frequency is up to 400KHz on AVR)

examples/ci2c_advanced/ci2c_advanced.ino

@@ -7,7 +7,7 @@
 	This example code is in the public domain.
 
 	created Jan 12 2017
-	latest mod Nov 21 2017
+	latest mod Nov 30 2017
 	by SMFSW
 */
 
@@ -66,12 +66,12 @@ bool I2C_wr_advanced(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data,
 {
 	if (bytes == 0)												{ return false; }
 
-	slave->reg_addr = reg_addr;
-
 	if (I2C_start() == false)									{ return false; }
 	if (I2C_sndAddr(slave, I2C_WRITE) == false)					{ return false; }
-	if (slave->cfg.reg_size)
+	if ((slave->cfg.reg_size) && (reg_addr != slave->reg_addr))	// Don't send address if writing next
 	{
+		slave->reg_addr = reg_addr;
+
 		if (slave->cfg.reg_size >= I2C_16B_REG)	// if size >2, 16bit address is used
 		{
 			if (I2C_wr8((uint8_t) (reg_addr >> 8)) == false)	{ return false; }
@@ -102,10 +102,10 @@ bool I2C_rd_advanced(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data,
 {
 	if (bytes == 0)													{ return false; }
 
-	slave->reg_addr = reg_addr;
+	if ((slave->cfg.reg_size) && (reg_addr != slave->reg_addr))	// Don't send address if reading next
-
-	if (slave->cfg.reg_size)
 	{
+		slave->reg_addr = reg_addr;
+
 		if (I2C_start() == false)									{ return false; }
 		if (I2C_sndAddr(slave, I2C_WRITE) == false)					{ return false; }
 		if (slave->cfg.reg_size >= I2C_16B_REG)	// if size >2, 16bit address is used

library.properties

@@ -1,5 +1,5 @@
 name=cI2C
-version=1.1
+version=1.2
 author=SMFSW <xgarmanboziax@gmail.com>
 maintainer=SMFSW <xgarmanboziax@gmail.com>
 sentence=Arduino Hardware I2C for AVR (in plain c)

src/ci2c.c

@@ -1,18 +1,14 @@
 /*!\file ci2c.c
 ** \author SMFSW
-** \version 1.1
+** \version 1.2
 ** \copyright MIT SMFSW (2017)
 ** \brief arduino master i2c in plain c code
+** \warning Don't access (r/w) last 16b internal address byte alone right after init, this would lead to hazardous result (in such case, make a dummy read of addr 0 before)
 **/
 
 // TODO: add interrupt vector / callback for it operations (if not too messy)
 // TODO: consider interrupts at least for RX when slave (and TX when master)
 
-// TODO: change contigous r/w operations so it doesn't send internal address again
-
-// TODO: split functions & headers
-
-
 #include "ci2c.h"
 
 #define START					0x08
@@ -69,7 +65,7 @@ void I2C_slave_init(I2C_SLAVE * slave, const uint8_t sl_addr, const I2C_INT_SIZE
 	(void) I2C_slave_set_reg_size(slave, reg_sz);
 	I2C_slave_set_rw_func(slave, (ci2c_fct_ptr) I2C_wr, I2C_WRITE);
 	I2C_slave_set_rw_func(slave, (ci2c_fct_ptr) I2C_rd, I2C_READ);
-	slave->reg_addr = 0;
+	slave->reg_addr = (uint16_t) -1;	// To be sure to send address on first access (warning: unless last 16b byte address is accessed alone)
 	slave->status = I2C_OK;
 }
 
@@ -393,12 +389,12 @@ static bool I2C_wr(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data, c
 {
 	if (bytes == 0)												{ return false; }
 
-	(void) I2C_slave_set_reg_addr(slave, reg_addr);
-
 	if (I2C_start() == false)									{ return false; }
 	if (I2C_sndAddr(slave, I2C_WRITE) == false)					{ return false; }
-	if (slave->cfg.reg_size)
+	if ((slave->cfg.reg_size) && (reg_addr != slave->reg_addr))	// Don't send address if writing next
 	{
+		(void) I2C_slave_set_reg_addr(slave, reg_addr);
+
 		if (slave->cfg.reg_size >= I2C_16B_REG)	// if size >2, 16bit address is used
 		{
 			if (I2C_wr8((uint8_t) (reg_addr >> 8)) == false)	{ return false; }
@@ -429,10 +425,10 @@ static bool I2C_rd(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data, c
 {
 	if (bytes == 0)													{ return false; }
 
-	(void) I2C_slave_set_reg_addr(slave, reg_addr);
+	if ((slave->cfg.reg_size) && (reg_addr != slave->reg_addr))	// Don't send address if reading next
-
-	if (slave->cfg.reg_size)	// If start register has to be sent first
 	{
+		(void) I2C_slave_set_reg_addr(slave, reg_addr);
+
 		if (I2C_start() == false)									{ return false; }
 		if (I2C_sndAddr(slave, I2C_WRITE) == false)					{ return false; }
 		if (slave->cfg.reg_size >= I2C_16B_REG)	// if size >2, 16bit address is used

src/ci2c.h

@@ -1,8 +1,9 @@
 /*!\file ci2c.h
 ** \author SMFSW
-** \version 1.1
+** \version 1.2
 ** \copyright MIT SMFSW (2017)
 ** \brief arduino i2c in plain c declarations
+** \warning Don't access (r/w) last 16b internal address byte alone right after init, this would lead to hazardous result (in such case, make a dummy read of addr 0 before)
 **/
 /****************************************************************/
 #ifndef __CI2C_H__
@@ -212,7 +213,6 @@ I2C_STATUS I2C_write(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data,
 ** \return I2C_STATUS status of write attempt
 **/
 inline I2C_STATUS __attribute__((__always_inline__)) I2C_write_next(I2C_SLAVE * slave, uint8_t * data, const uint16_t bytes) {
-	// TODO: implement read next so that it doesn't have to send start register address again
 	return I2C_write(slave, slave->reg_addr, data, bytes); }
 
 /*!\brief This function reads data from the address specified and stores this
@@ -233,7 +233,6 @@ I2C_STATUS I2C_read(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data,
 ** \return I2C_STATUS status of read attempt
 **/
 inline I2C_STATUS __attribute__((__always_inline__)) I2C_read_next(I2C_SLAVE * slave, uint8_t * data, const uint16_t bytes) {
-	// TODO: implement read next so that it doesn't have to send start register address again
 	return I2C_read(slave, slave->reg_addr, data, bytes); }