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I2C Fastmode on lm4f Stellaris #343

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I2C Fastmode on lm4f Stellaris #343

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a7ba256
FastMode selectable in setModule fuction (Disabled by default)
Mar 16, 2014
eafe1dc
Delay reduced to 200us in slow mode
Mar 16, 2014
459bcbd
Some comments
Mar 16, 2014
892c185
Reference to test data and explanation added
Mar 16, 2014
e4173ac
I2C Fastmode Plus implemented
Apr 28, 2014
54f92dc
Some documentation
Apr 28, 2014
18c8016
Lastedit date
Apr 28, 2014
f212f4d
Documentation is in the code
AxelTB May 7, 2014
04ca2fd
Sync with original Repo
May 23, 2014
cadbd6b
Merge branch 'master' of https://github.com/AxelTB/Energia
May 23, 2014
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77 changes: 56 additions & 21 deletions hardware/lm4f/libraries/Wire/Wire.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@

Modified 23 November 2006 by David A. Mellis
Modified 28 September 2010 by Mark Sproul
Modified 29 April 2014 by Alessio Graziano
*/

#include <stdlib.h>
Expand Down Expand Up @@ -61,34 +62,36 @@

#define NOT_ACTIVE 0xA

#define SLOWMODE_DELAYUS 200 ///Delay in microseconds after master busy wait in non-fast Mode

static const unsigned long g_uli2cMasterBase[4] =
{
#ifdef TARGET_IS_BLIZZARD_RB1
I2C0_BASE, I2C1_BASE,
I2C0_BASE, I2C1_BASE,
I2C2_BASE, I2C3_BASE
#else
#ifdef __TM4C129XNCZAD__
I2C0_BASE, I2C1_BASE,
I2C0_BASE, I2C1_BASE,
I2C2_BASE, I2C3_BASE
#endif
#ifdef __TM4C1294NCPDT__
I2C0_BASE, I2C2_BASE,
I2C0_BASE, I2C2_BASE,
I2C8_BASE, I2C7_BASE
#endif
#endif
};
static const unsigned long g_uli2cSlaveBase[4] =
{
#ifdef TARGET_IS_BLIZZARD_RB1
I2C0_BASE, I2C1_BASE,
I2C0_BASE, I2C1_BASE,
I2C2_BASE, I2C3_BASE
#else
#ifdef __TM4C129XNCZAD__
I2C0_BASE, I2C1_BASE,
I2C0_BASE, I2C1_BASE,
I2C2_BASE, I2C3_BASE
#endif
#ifdef __TM4C1294NCPDT__
I2C0_BASE, I2C2_BASE,
I2C0_BASE, I2C2_BASE,
I2C8_BASE, I2C7_BASE
#endif
#endif
Expand Down Expand Up @@ -122,15 +125,15 @@ static const unsigned long g_uli2cInt[4] =
static const unsigned long g_uli2cPeriph[4] =
{
#ifdef TARGET_IS_BLIZZARD_RB1
SYSCTL_PERIPH_I2C0, SYSCTL_PERIPH_I2C1,
SYSCTL_PERIPH_I2C0, SYSCTL_PERIPH_I2C1,
SYSCTL_PERIPH_I2C2, SYSCTL_PERIPH_I2C3
#else
#ifdef __TM4C129XNCZAD__
SYSCTL_PERIPH_I2C0, SYSCTL_PERIPH_I2C1,
SYSCTL_PERIPH_I2C0, SYSCTL_PERIPH_I2C1,
SYSCTL_PERIPH_I2C2, SYSCTL_PERIPH_I2C3
#endif
#ifdef __TM4C1294NCPDT__
SYSCTL_PERIPH_I2C0, SYSCTL_PERIPH_I2C2,
SYSCTL_PERIPH_I2C0, SYSCTL_PERIPH_I2C2,
SYSCTL_PERIPH_I2C8, SYSCTL_PERIPH_I2C7
#endif
#endif
Expand Down Expand Up @@ -246,6 +249,7 @@ TwoWire::TwoWire()
TwoWire::TwoWire(unsigned long module)
{
i2cModule = module;
speedMode = I2C_SPEED_STANDARD; //Standard Speed by default for backward compatibility
}

// Private Methods //////////////////////////////////////////////////////////////
Expand All @@ -267,7 +271,8 @@ uint8_t TwoWire::getRxData(unsigned long cmd) {
ROM_I2CMasterControl(MASTER_BASE, I2C_MASTER_CMD_BURST_RECEIVE_ERROR_STOP);
}
else {
delay(1);
if(speedMode==I2C_SPEED_STANDARD) //Fast modes works without delay (Tested on stellaris&GY-80)
delayMicroseconds(SLOWMODE_DELAYUS);
rxBuffer[rxWriteIndex] = ROM_I2CMasterDataGet(MASTER_BASE);
rxWriteIndex = (rxWriteIndex + 1) % BUFFER_LENGTH;
}
Expand All @@ -276,7 +281,8 @@ uint8_t TwoWire::getRxData(unsigned long cmd) {
}

uint8_t TwoWire::sendTxData(unsigned long cmd, uint8_t data) {
delay(1);
if(speedMode==I2C_SPEED_STANDARD) //Fast mode works without delay (Tested on stellaris&GY-80)
delayMicroseconds(SLOWMODE_DELAYUS);
ROM_I2CMasterDataPut(MASTER_BASE, data);

HWREG(MASTER_BASE + I2C_O_MCS) = cmd;
Expand Down Expand Up @@ -305,7 +311,13 @@ void TwoWire::forceStop(void) {
//bring the bus back to it's erroneous state
ROM_SysCtlPeripheralReset(g_uli2cPeriph[i2cModule]);
while(!ROM_SysCtlPeripheralReady(g_uli2cPeriph[i2cModule]));
ROM_I2CMasterInitExpClk(MASTER_BASE, F_CPU, false);
ROM_I2CMasterInitExpClk(MASTER_BASE, F_CPU, speedMode);//Bus speed

if(speedMode==I2C_SPEED_FASTMODE_PLUS)//Force 1Mhz
{
uint32_t ui32TPR = ((F_CPU + (2 * 10 * 1000000l) - 1) / (2 * 10 * 1000000l)) - 1;
HWREG(MASTER_BASE + I2C_O_MTPR) = ui32TPR;
}
}

// Public Methods //////////////////////////////////////////////////////////////
Expand All @@ -325,20 +337,32 @@ void TwoWire::begin(void)
ROM_GPIOPinConfigure(g_uli2cConfig[i2cModule][1]);
ROM_GPIOPinTypeI2C(g_uli2cBase[i2cModule], g_uli2cSDAPins[i2cModule]);
ROM_GPIOPinTypeI2CSCL(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]);
ROM_I2CMasterInitExpClk(MASTER_BASE, F_CPU, false);//max bus speed=400kHz for gyroscope
ROM_I2CMasterInitExpClk(MASTER_BASE, F_CPU, speedMode);//Bus speed

if(speedMode==I2C_SPEED_FASTMODE_PLUS)//Force 1Mhz
{
uint32_t ui32TPR = ((F_CPU + (2 * 10 * 1000000l) - 1) / (2 * 10 * 1000000l)) - 1;
HWREG(MASTER_BASE + I2C_O_MTPR) = ui32TPR;
}


//force a stop condition
if(!ROM_GPIOPinRead(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]))
forceStop();

//Handle any startup issues by pulsing SCL
if(ROM_I2CMasterBusBusy(MASTER_BASE) || ROM_I2CMasterErr(MASTER_BASE)
if(ROM_I2CMasterBusBusy(MASTER_BASE) || ROM_I2CMasterErr(MASTER_BASE)
|| !ROM_GPIOPinRead(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule])){
uint8_t doI = 0;
ROM_GPIOPinTypeGPIOOutput(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule]);
unsigned long mask = 0;
do{
for(unsigned long i = 0; i < 10 ; i++) {
if(speedMode==I2C_SPEED_FASTMODE_PLUS)
ROM_SysCtlDelay(F_CPU/1000000/3);//1000Hz=desired frequency, delay iteration=3 cycles
else if(speedMode==I2C_SPEED_FASTMODE)
ROM_SysCtlDelay(F_CPU/400000/3);//400Hz=desired frequency, delay iteration=3 cycles
else
ROM_SysCtlDelay(F_CPU/100000/3);//100Hz=desired frequency, delay iteration=3 cycles
mask = (i%2) ? g_uli2cSCLPins[i2cModule] : 0;
ROM_GPIOPinWrite(g_uli2cBase[i2cModule], g_uli2cSCLPins[i2cModule], mask);
Expand Down Expand Up @@ -378,8 +402,8 @@ void TwoWire::begin(uint8_t address)
//Setup as a slave device
ROM_I2CMasterDisable(MASTER_BASE);
I2CSlaveEnable(SLAVE_BASE);
I2CSlaveInit(SLAVE_BASE, address);
I2CSlaveInit(SLAVE_BASE, address);

ROM_IntMasterEnable();

}
Expand Down Expand Up @@ -569,7 +593,7 @@ int TwoWire::available(void)
int TwoWire::read(void)
{
int value = -1;

// get each successive byte on each call
if(!RX_BUFFER_FULL){
value = rxBuffer[rxReadIndex];
Expand All @@ -585,7 +609,7 @@ int TwoWire::read(void)
int TwoWire::peek(void)
{
int value = -1;

if(!RX_BUFFER_EMPTY){
value = rxBuffer[rxReadIndex];
}
Expand Down Expand Up @@ -637,7 +661,7 @@ void TwoWire::I2CIntHandler(void) {

break;

case(I2C_SLAVE_ACT_TREQ)://data requested
case(I2C_SLAVE_ACT_TREQ)://data requested

if(startDetected) {
uint8_t oldWriteIndex = txWriteIndex;
Expand Down Expand Up @@ -681,13 +705,24 @@ I2CIntHandler(void)
{
Wire.I2CIntHandler();
}

void TwoWire::setModule(unsigned long _i2cModule)
/***
* @brief: Set module and mode
* @param: _speedMode: I2C Speed selection
* I2C_SPEED_STANDARD: 100kbps
* I2C_SPEED_FASTMODE: 400kbps
* I2C_SPEED_FASTMODE_PLUS: 1Mbps
**/
void TwoWire::setModule(unsigned long _i2cModule,uint8_t _speedMode)
{
i2cModule = _i2cModule;
speedMode = _speedMode;
if(slaveAddress != 0) begin(slaveAddress);
else begin();
}
void TwoWire::setModule(unsigned long _i2cModule)
{
setModule(_i2cModule,I2C_SPEED_STANDARD); //Standard mode (100k) by default for backward compatibility
}

//Preinstantiate Object
TwoWire Wire;
6 changes: 5 additions & 1 deletion hardware/lm4f/libraries/Wire/Wire.h
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,8 @@

#define BOOST_PACK_WIRE 3

enum{I2C_SPEED_STANDARD=0,I2C_SPEED_FASTMODE,I2C_SPEED_FASTMODE_PLUS};

class TwoWire : public Stream
{

Expand All @@ -29,14 +31,15 @@ class TwoWire : public Stream

static uint8_t i2cModule;
static uint8_t slaveAddress;
uint8_t speedMode;

static uint8_t transmitting;
static uint8_t currentState;
static void (*user_onRequest)(void);
static void (*user_onReceive)(int);
static void onRequestService(void);
static void onReceiveService(uint8_t*, int);

uint8_t getRxData(unsigned long cmd);
uint8_t sendTxData(unsigned long cmd, uint8_t data);
void forceStop(void);
Expand Down Expand Up @@ -74,6 +77,7 @@ class TwoWire : public Stream
//Stellarpad-specific functions
void I2CIntHandler(void);
void setModule(unsigned long);
void setModule(unsigned long,uint8_t);

};

Expand Down