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-rw-r--r--main.c233
1 files changed, 148 insertions, 85 deletions
diff --git a/main.c b/main.c
index f83d090..4858a5e 100644
--- a/main.c
+++ b/main.c
@@ -1,12 +1,12 @@
-/* cpu freq */
+/* cpu runs at 1mhz */
#define F_CPU 1000000
#include <avr/io.h>
+#include <avr/interrupt.h>
#include <util/delay.h>
#include <util/twi.h>
#include <stdio.h>
-
-/* cpu runs at 1mhz */
+#include <stdbool.h>
/* i2c device addresses */
#define L3GD20 0b11010100
@@ -16,29 +16,83 @@
#define LIS302DL_WHOAMI 0xf
#define LIS302DL_CTRLREG1 0x20
-void twStart () {
- /* disable stop, reset twint, enable start, enable i2c */
- TWCR = (TWCR & ~(1 << TWSTO)) | (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
+typedef enum {
+ TWST_WAIT = 0,
+ TWST_OK = 1,
+ TWST_ERR = 2,
+} twStatus;
+
+typedef struct {
+ uint8_t address;
+ uint8_t subaddress;
+ uint8_t data;
+ uint8_t step;
+ twStatus status;
+} twReq;
+
+volatile twReq twr;
+
+void twStartRaw () {
+ /* disable stop, enable interrupt, reset twint, enable start, enable i2c */
+ TWCR = (TWCR & ~(1 << TWSTO)) | (1 << TWIE) | (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
+}
+
+void twStopRaw () {
+ /* disable start, enable interrupt, reset twint, enable stop, enable i2c */
+ TWCR = (TWCR & ~(1 << TWSTA)) | (1 << TWIE) | (1 << TWINT) | (1 << TWSTO) | (1 << TWEN);
}
-void twStop () {
- /* disable start, reset twint, enable stop, enable i2c */
- TWCR = (TWCR & ~(1 << TWSTA)) | (1 << TWINT) | (1 << TWSTO) | (1 << TWEN);
+void twFlushRaw () {
+ /* disable start/stop, enable interrupt, reset twint, enable i2c */
+ TWCR = (TWCR & ~((1 << TWSTA) | (1 << TWSTO) | (1 << TWEA))) | (1 << TWIE) | (1 << TWINT) | (1 << TWEN);
}
-void twFlush () {
- /* disable start/stop, reset twint, enable i2c */
- TWCR = (TWCR & ~((1 << TWSTA) | (1 << TWSTO))) | (1 << TWINT) | (1 << TWEN);
+/* flush and send master ack */
+void twFlushContRaw () {
+ /* disable start/stop, enable interrupt, reset twint, enable i2c, send master ack */
+ TWCR = (TWCR & ~((1 << TWSTA) | (1 << TWSTO))) | (1 << TWIE) | (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
}
-void twWait () {
+void twWaitRaw () {
while (!(TWCR & (1 << TWINT)));
}
+bool twWriteRaw (uint8_t data) {
+ TWDR = data;
+ if (TWCR & (1 << TWWC)) {
+ printf("write collision\n");
+ return false;
+ } else {
+ return true;
+ }
+}
+
void twInit () {
/* set scl to 3.6 kHz (at 1Mhz CPU speed)*/
TWBR = 2;
TWSR |= 0x3; /* set prescaler to 64 */
+
+ twr.status = TWST_ERR;
+}
+
+/* high-level write
+ */
+static bool twWrite (uint8_t address, uint8_t subaddress, uint8_t data) {
+ /* do not start if request is pending */
+ if (twr.status == TWST_WAIT) {
+ return false;
+ }
+
+ twr.address = address | TW_WRITE;
+ twr.subaddress = subaddress;
+ twr.data = data;
+ twr.step = 0;
+ twr.status = TWST_WAIT;
+ /* wait for stop finish */
+ while (TW_STATUS != 0xf8);
+ twStartRaw ();
+
+ return true;
}
void ledInit () {
@@ -99,6 +153,48 @@ void cpuInit () {
CLKPR = 0b00000011;
}
+ISR(TWI_vect) {
+ printf ("interupt hit with step %i\n", twr.step);
+ switch (twr.step) {
+ case 0:
+ if (TW_STATUS == TW_START) {
+ twWriteRaw (twr.address);
+ twFlushRaw ();
+ } else {
+ twr.status = TWST_ERR;
+ }
+ break;
+
+ case 1:
+ if (TW_STATUS == TW_MT_SLA_ACK) {
+ twWriteRaw (twr.subaddress);
+ twFlushRaw ();
+ } else {
+ twr.status = TWST_ERR;
+ }
+ break;
+
+ case 2:
+ if (TW_STATUS == TW_MT_DATA_ACK) {
+ twWriteRaw (twr.data);
+ twFlushRaw ();
+ } else {
+ twr.status = TWST_ERR;
+ }
+ break;
+
+ case 3:
+ if (TW_STATUS == TW_MT_DATA_ACK) {
+ twStopRaw ();
+ twr.status = TWST_OK;
+ } else {
+ twr.status = TWST_ERR;
+ }
+ break;
+ }
+ ++twr.step;
+}
+
int main(void) {
cpuInit ();
ledInit ();
@@ -110,62 +206,19 @@ int main(void) {
printf ("initialization done\n");
+ sei ();
/* disable power-down-mode */
- twStart ();
- twWait ();
- unsigned char status = 0x0;
-
- /* check status code */
- if ((status = TW_STATUS) == TW_START) {
- /* write device address and write bit */
- TWDR = LIS302DL | TW_WRITE;
- if (TWCR & (1 << TWWC)) {
- printf("write collision\n");
- }
- twFlush ();
- twWait ();
- if ((status = TW_STATUS) == TW_MT_SLA_ACK) {
- } else {
- printf ("fail with code %x\n", status);
- }
-
- /* write subaddress (actually i2c data) */
- TWDR = LIS302DL_CTRLREG1;
- if (TWCR & (1 << TWWC)) {
- printf("write collision\n");
- }
- twFlush ();
- twWait ();
- if ((status = TW_STATUS) == TW_MT_DATA_ACK) {
- } else {
- printf ("fail with code %x\n", status);
- }
-
- /* write actual data */
- TWDR = 0b01000111;
- if (TWCR & (1 << TWWC)) {
- printf("write collision\n");
- }
- twFlush ();
- twWait ();
- if ((status = TW_STATUS) == TW_MT_DATA_ACK) {
- } else {
- printf ("fail with code %x\n", status);
- }
-
- twStop ();
- _delay_ms (100);
- } else {
- printf ("write: start failed\n");
+ if (!twWrite (LIS302DL, LIS302DL_CTRLREG1, 0b01000111)) {
+ printf ("cannot start write\n");
}
+ while (twr.status == TWST_WAIT);
+ printf ("final twi status was %i\n", twr.status);
+ cli ();
while (1) {
- unsigned char reg[] = {0x29, 0x2b, 0x2d};
signed char val[6];
- //unsigned char reg[] = {0xf, 0x20, 0x21, 0x22, 0x23, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2d, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f};
- for (unsigned char i = 0; i < sizeof (reg)/sizeof(*reg); i++) {
- twStart ();
- twWait ();
+ twStartRaw ();
+ twWaitRaw ();
unsigned char status = 0x0;
/* check status code */
@@ -176,28 +229,28 @@ int main(void) {
if (TWCR & (1 << TWWC)) {
printf("write collision\n");
}
- twFlush ();
- twWait ();
+ twFlushRaw ();
+ twWaitRaw ();
if ((status = TW_STATUS) == TW_MT_SLA_ACK) {
} else {
printf ("fail with code %x\n", status);
}
- /* write subaddress (actually i2c data) */
- TWDR = reg[i];
+ /* auto increment + subaddress */
+ TWDR = (1 << 7) | 0x28;
if (TWCR & (1 << TWWC)) {
printf("write collision\n");
}
- twFlush ();
- twWait ();
+ twFlushRaw ();
+ twWaitRaw ();
if ((status = TW_STATUS) == TW_MT_DATA_ACK) {
} else {
printf ("fail with code %x\n", status);
}
/* repeated start */
- twStart ();
- twWait ();
+ twStartRaw ();
+ twWaitRaw ();
if ((status = TW_STATUS) == TW_REP_START) {
} else {
printf ("fail with code %x\n", status);
@@ -208,24 +261,35 @@ int main(void) {
if (TWCR & (1 << TWWC)) {
printf("write collision\n");
}
- twFlush ();
- twWait ();
+ twFlushRaw ();
+ twWaitRaw ();
if ((status = TW_STATUS) == TW_MR_SLA_ACK) {
} else {
printf ("fail with code %x\n", status);
}
- /* clear twint and wait for response */
- twFlush ();
- twWait ();
- if ((status = TW_STATUS) == TW_MR_DATA_NACK) {
- } else {
- printf ("fail with code %x\n", status);
+ for (uint8_t i = 0; i < 6; i++) {
+ /* clear twint and wait for response */
+ if (i < 5) {
+ twFlushContRaw ();
+ twWaitRaw ();
+ if ((status = TW_STATUS) == TW_MR_DATA_ACK) {
+ } else {
+ printf ("fail with code %x in val %i\n", status, i);
+ }
+ } else {
+ twFlushRaw ();
+ twWaitRaw ();
+ if ((status = TW_STATUS) == TW_MR_DATA_NACK) {
+ } else {
+ printf ("fail with code %x in val %i\n", status, i);
+ }
+ }
+ unsigned char ret = TWDR;
+ val[i] = ret;
}
- unsigned char ret = TWDR;
- val[i] = ret;
- twStop ();
+ twStopRaw ();
/* there is no way to tell whether stop has been sent or not, just wait */
_delay_ms (10);
@@ -233,9 +297,8 @@ int main(void) {
printf ("fail with code %x\n", status);
_delay_ms (1000);
}
- }
//printf ("%i/%i/%i\n", (val[1] << 8) | val[0], (val[3] << 8) | val[2], (val[5] << 8) | val[4]);
- printf ("%i/%i/%i\n", val[0], val[1], val[2]);
+ printf ("%i/%i/%i\n", val[1], val[3], val[5]);
}
while (1);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-26 08:39:12 +0000