X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=drv%2Ftwi.c;h=d0c6537428369569fd50cea491eeaf89dbf719ac;hb=f52e46baa21748f30f30a9e725edbf90b420ed24;hp=ff52b68af5c5fc6e956bf2e827856e78b5f9c71a;hpb=17f6b83057f60aae39ed0124f8015fc4c8d578b6;p=bertos.git

diff --git a/drv/twi.c b/drv/twi.c
index ff52b68a..d0c65374 100755
--- a/drv/twi.c
+++ b/drv/twi.c
@@ -1,8 +1,8 @@
-/*!
+/**
  * \file
  * <!--
  * Copyright 2003, 2004, 2005 Develer S.r.l. (http://www.develer.com/)
- * This file is part of DevLib - See devlib/README for information.
+ * This file is part of DevLib - See README.devlib for information.
  * -->
  *
  * \brief Driver for the AVR ATMega TWI (implementation)
@@ -15,31 +15,47 @@
 
 /*#*
  *#* $Log$
+ *#* 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.
+ *#*
  *#* Revision 1.1  2005/01/06 16:09:40  aleph
  *#* Split twi/eeprom functions from eeprom module in separate twi module
  *#*
  *#*/
 
 #include "twi.h"
-#include "config.h"
-#include <debug.h>
+
+#include <cfg/debug.h>
+#include <cfg/cpu.h>
+#include <cfg/macros.h> // BV()
 #include <hw.h>
-#include <cpu.h>
+#include <appconfig.h>
 
-#include <avr/twi.h>
+#include <compat/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
-/*@}*/
+#define READ_BIT BV(0)
 
 
-/*!
+/**
  * Send START condition on the bus.
  *
  * \return true on success, false otherwise.
@@ -57,15 +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
@@ -74,7 +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;
 
@@ -91,18 +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;
 
@@ -116,16 +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.
  *
@@ -137,21 +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.
@@ -196,7 +225,7 @@ bool twi_recv(void *_buf, size_t count)
 }
 
 
-/*!
+/**
  * Initialize TWI module.
  */
 void twi_init(void)
@@ -223,10 +252,13 @@ void twi_init(void)
 		 * Set speed:
 		 * F = CLOCK_FREQ / (16 + 2*TWBR * 4^TWPS)
 		 */
-		#define TWI_FREQ  300000L /* ~300 kHz */
+		#ifndef CONFIG_TWI_FREQ
+			#warning Using default value of 300000L for CONFIG_TWI_FREQ
+			#define CONFIG_TWI_FREQ  300000L /* ~300 kHz */
+		#endif
 		#define TWI_PRESC 1       /* 4 ^ TWPS */
 
-		TWBR = (CLOCK_FREQ / (2 * TWI_FREQ * TWI_PRESC)) - (8 / TWI_PRESC);
+		TWBR = (CLOCK_FREQ / (2 * CONFIG_TWI_FREQ * TWI_PRESC)) - (8 / TWI_PRESC);
 		TWSR = 0;
 		TWCR = BV(TWEN);
 	);