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Offload I2C work onto interrupts. For now, we just spin while waiting

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for the I2C activity to complete.
This commit is contained in:
Gavan Fantom
2011-05-26 01:57:16 +00:00
parent 6a3c096bc5
commit 0f508fb424
5 changed files with 197 additions and 135 deletions
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161
i2c.c
View File

@@ -1,5 +1,6 @@
#include "i2c.h"
#include "interrupt.h"
#define I2CBASE 0xE001C000
@@ -21,6 +22,11 @@
#define SI (IREG(I2CONSET) & SIFLAG)
void __attribute__((interrupt("IRQ"))) i2c_interrupt_handler(void);
struct i2c_transaction *i2c_transaction;
int i2c_bytes;
void init_i2c(void)
{
IREG(I2CONSET) = 0x40; /* Enable I2C ready for Master Tx */
@@ -32,17 +38,7 @@ void init_i2c(void)
IWREG(I2SCLL) = 73; /* ~100kHz */
IWREG(I2SCLH) = 73;
#endif
}
int i2cstat;
int i2c_wait(void)
{
int stat;
while (!SI);
stat = IREG(I2STAT);
i2cstat = stat;
return stat;
interrupt_register(I2C0, i2c_interrupt_handler);
}
int i2c_conreg(void)
@@ -55,61 +51,110 @@ int i2c_statreg(void)
return IREG(I2STAT);
}
bool i2c_send_start(void)
bool i2c_busy(void)
{
return i2c_transaction != NULL;
}
bool i2c_start_transaction(struct i2c_transaction *t)
{
if (i2c_transaction)
return FALSE;
i2c_transaction = t;
*(t->result) = I2C_IN_PROGRESS;
/* Paranoia in case we left things in a bad state */
IREG(I2CONCLR) = STOFLAG | STAFLAG;
/* Set it all going */
IREG(I2CONSET) = STAFLAG;
switch (i2c_wait()) {
case 0x08:
case 0x10:
return TRUE;
default:
i2c_send_stop();
return FALSE;
}
}
bool i2c_send_address(int addr, bool write)
void __attribute__((interrupt("IRQ"))) i2c_interrupt_handler(void)
{
return i2c_send_data((addr<<1) + (write?0:1));
}
int stat = IREG(I2STAT);
bool i2c_send_data(unsigned int data)
{
IREG(I2DAT) = data;
IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG;
switch (i2c_wait()) {
case 0x18:
case 0x28:
case 0x40:
return TRUE;
default:
i2c_send_stop();
return FALSE;
}
}
bool i2c_receive_data(unsigned int *data, bool last)
{
if (!last)
IREG(I2CONSET) = AAFLAG;
IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG | (last?AAFLAG:0);
switch (i2c_wait()) {
case 0x50:
case 0x58:
*data = IREG(I2DAT);
return TRUE;
default:
i2c_send_stop();
return FALSE;
}
}
void i2c_send_stop(void)
{
IREG(I2CONCLR) = STAFLAG | AAFLAG;
if (!i2c_transaction) {
IREG(I2CONSET) = STOFLAG;
IREG(I2CONCLR) = SIFLAG;
/* Don't think we need to wait here. Could be wrong. */
IREG(I2CONCLR) = STAFLAG | AAFLAG | SIFLAG;
interrupt_clear();
return;
}
switch (stat) {
case 0x08: /* START transmitted */
case 0x10: /* repeated START transmitted */
IREG(I2DAT) = i2c_transaction->address;
IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG;
i2c_bytes = 0;
break;
case 0x18: /* SA+W transmitted, ACK received */
case 0x28: /* data transmitted, ACK received */
if (i2c_bytes < i2c_transaction->bytes) {
IREG(I2DAT) = i2c_transaction->data[i2c_bytes++];
IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG;
} else {
*(i2c_transaction->result) = I2C_SUCCESS;
if (i2c_transaction->next) {
i2c_transaction = i2c_transaction->next;
i2c_bytes = 0;
IREG(I2CONSET) = STAFLAG;
IREG(I2CONCLR) = STOFLAG | AAFLAG | SIFLAG;
} else {
i2c_transaction = NULL;
IREG(I2CONSET) = STOFLAG;
IREG(I2CONCLR) = STAFLAG | AAFLAG | SIFLAG;
}
}
break;
case 0x50: /* data received, ACK returned */
i2c_transaction->data[i2c_bytes++] = IREG(I2DAT);
/* fall through */
case 0x40: /* SA+R transmitted, ACK received */
if (i2c_bytes < (i2c_transaction->bytes-1)) {
IREG(I2CONSET) = AAFLAG;
IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG;
} else {
IREG(I2CONCLR) = STAFLAG | STOFLAG | SIFLAG
| AAFLAG;
}
break;
case 0x58: /* data received, NACK returned */
i2c_transaction->data[i2c_bytes] = IREG(I2DAT);
*(i2c_transaction->result) = I2C_SUCCESS;
if (i2c_transaction->next) {
i2c_transaction = i2c_transaction->next;
i2c_bytes = 0;
IREG(I2CONSET) = STAFLAG;
IREG(I2CONCLR) = STOFLAG | AAFLAG | SIFLAG;
} else {
i2c_transaction = NULL;
IREG(I2CONSET) = STOFLAG;
IREG(I2CONCLR) = STAFLAG | AAFLAG | SIFLAG;
}
break;
case 0x20: /* SA+W transmitted, NACK received */
case 0x30: /* data transmitted, NACK received */
case 0x48: /* SA+R transmitted, NACK received */
case 0x38: /* arbitration lost during SA+W or data */
case 0x00: /* bus error */
*(i2c_transaction->result) = I2C_FAIL;
i2c_transaction = NULL;
IREG(I2CONSET) = STOFLAG;
IREG(I2CONCLR) = STAFLAG | AAFLAG | SIFLAG;
break;
/* We don't handle slave mode */
}
interrupt_clear();
}

26
i2c.h
View File

@@ -2,16 +2,26 @@
#define __I2C_H
#include "types.h"
#define I2C_IN_PROGRESS 0
#define I2C_SUCCESS 1
#define I2C_FAIL 2
typedef int i2c_result;
struct i2c_transaction {
int address; /* i2c first byte, including address and r/w flag */
int bytes; /* number of bytes to read or write */
unsigned char *data; /* pointer to the data */
i2c_result *result; /* pointer to store the result */
struct i2c_transaction *next; /* NULL or next transaction */
};
void init_i2c(void);
extern int i2cstat;
int i2c_wait(void);
void i2c_go(void);
int i2c_conreg(void);
int i2c_statreg(void);
bool i2c_send_start(void);
bool i2c_send_address(int addr, bool write);
bool i2c_send_data(unsigned int data);
bool i2c_receive_data(unsigned int *data, bool last);
void i2c_send_stop(void);
bool i2c_start_transaction(struct i2c_transaction *t);
bool i2c_busy(void);
#endif /* __I2C_H */

15
main.c
View File

@@ -160,6 +160,7 @@ void average_sample(void)
int main(void) {
int i;
init_interrupt();
init_uart();
init_i2c();
@@ -193,8 +194,6 @@ int main(void) {
reply("Help is not available. Try a psychiatrist.");
break;
case 'T':
putstr("I2C status was: ");
puthex(i2cstat);
putstr(" I2C status is: ");
puthex(i2c_statreg());
reply(".");
@@ -202,18 +201,6 @@ int main(void) {
puthex(i2c_conreg());
reply(".");
break;
case 'S':
putstr("Sending START... ");
if (i2c_send_start())
reply("OK");
else
reply("FAIL");
break;
case 'O':
putstr("Sending STOP... ");
i2c_send_stop();
reply("sent");
break;
case 'I':
putstr("Initialising WMP... ");
if (wmp_init())

2
types.h
View File

@@ -5,4 +5,6 @@ typedef int bool;
#define TRUE 1
#define FALSE 0
#define NULL 0
#endif /* __TYPES_H */

124
wmp.c
View File

@@ -2,46 +2,77 @@
#include "wmp.h"
#include "i2c.h"
unsigned char wmp_init_command[2] = {0xfe, 0x04};
i2c_result wmp_result;
struct i2c_transaction wmp_init_transaction = {
(0x53 << 1) + 0, /* write */
2,
wmp_init_command,
&wmp_result,
NULL
};
unsigned char wmp_read_cal_command[1] = {0x20};
struct i2c_transaction wmp_read_cal_transaction2;
struct i2c_transaction wmp_read_cal_transaction = {
(0x53 << 1) + 0, /* write */
1,
wmp_read_cal_command,
&wmp_result,
&wmp_read_cal_transaction2
};
struct i2c_transaction wmp_read_cal_transaction2 = {
(0x53 << 1) + 1, /* read */
0x20,
wmp_calibration_data,
&wmp_result,
NULL
};
unsigned char wmp_sample_command[1] = {0x00};
unsigned char wmp_sample_data[6];
struct i2c_transaction wmp_sample_transaction2;
struct i2c_transaction wmp_sample_transaction = {
(0x52 << 1) + 0, /* write */
1,
wmp_sample_command,
&wmp_result,
&wmp_sample_transaction2
};
struct i2c_transaction wmp_sample_transaction2 = {
(0x52 << 1) + 1, /* read */
6,
wmp_sample_data,
&wmp_result,
NULL
};
bool wmp_init(void)
{
if (!i2c_send_start())
if (!i2c_start_transaction(&wmp_init_transaction))
return FALSE;
if (!i2c_send_address(0x53, TRUE))
return FALSE;
if (!i2c_send_data(0xfe))
return FALSE;
if (!i2c_send_data(0x04))
return FALSE;
i2c_send_stop();
return TRUE;
while (i2c_busy()) ;
return (wmp_result == I2C_SUCCESS);
}
unsigned char wmp_calibration_data[0x20];
bool wmp_read_calibration_data(void)
{
int i;
if (!i2c_send_start())
if (!i2c_start_transaction(&wmp_read_cal_transaction))
return FALSE;
if (!i2c_send_address(0x53, TRUE))
return FALSE;
if (!i2c_send_data(0x20))
return FALSE;
i2c_send_stop();
if (!i2c_send_start())
return FALSE;
if (!i2c_send_address(0x53, FALSE))
return FALSE;
for (i = 0; i < 0x20; i++) {
unsigned int data;
if (!i2c_receive_data(&data, (i == 0x1f)))
return FALSE;
wmp_calibration_data[i] = data;
}
i2c_send_stop();
return TRUE;
while (i2c_busy());
return (wmp_result == I2C_SUCCESS);
}
unsigned int wmp_yaw;
@@ -66,35 +97,22 @@ bool wmp_roll_fast;
bool wmp_sample(void)
{
int i;
unsigned int b[6];
if (!i2c_start_transaction(&wmp_sample_transaction))
return FALSE;
if (!i2c_send_start())
return FALSE;
if (!i2c_send_address(0x52, TRUE))
return FALSE;
if (!i2c_send_data(0x00))
return FALSE;
i2c_send_stop();
while (i2c_busy());
if (!i2c_send_start())
if (wmp_result != I2C_SUCCESS)
return FALSE;
if (!i2c_send_address(0x52, FALSE))
return FALSE;
for (i = 0; i < 6; i++) {
if (!i2c_receive_data(&(b[i]), (i == 5)))
return FALSE;
}
i2c_send_stop();
wmp_yaw = ((b[3]>>2)<<8) + b[0];
wmp_pitch = ((b[4]>>2)<<8) + b[1];
wmp_roll = ((b[5]>>2)<<8) + b[2];
wmp_yaw = ((wmp_sample_data[3]>>2)<<8) + wmp_sample_data[0];
wmp_pitch = ((wmp_sample_data[4]>>2)<<8) + wmp_sample_data[1];
wmp_roll = ((wmp_sample_data[5]>>2)<<8) + wmp_sample_data[2];
/* XXX We don't take into account the fast/slow mode flag here */
wmp_yaw_fast = !(b[3] & 0x2);
wmp_pitch_fast = !(b[3] & 0x1);
wmp_roll_fast = !(b[4] & 0x2);
wmp_yaw_fast = !(wmp_sample_data[3] & 0x2);
wmp_pitch_fast = !(wmp_sample_data[3] & 0x1);
wmp_roll_fast = !(wmp_sample_data[4] & 0x2);
return TRUE;
}