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authorLars-Dominik Braun <lars@6xq.net>2015-01-20 15:51:50 +0100
committerLars-Dominik Braun <lars@6xq.net>2015-01-20 15:51:50 +0100
commit2c40f4a0e5c9e9bda8d3b59553abf01abe97c5cd (patch)
treeb384758140112e5ec55acd20141339b83d1f1244
parent1f6686fe0f16a3620ee4f0ad012a2add5e03c584 (diff)
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i2c: twRequests returns false if bus is busy
-rw-r--r--gyro.c38
-rw-r--r--i2c.c8
2 files changed, 25 insertions, 21 deletions
diff --git a/gyro.c b/gyro.c
index a533e3f..14e25ed 100644
--- a/gyro.c
+++ b/gyro.c
@@ -82,21 +82,21 @@ static void gyroProcessTicks () {
*/
bool gyroProcess () {
switch (state) {
- case START_REQUEST:
- if (twr.status == TWST_OK) {
- /* configuration:
- * disable power-down-mode, enable z
- * defaults
- * high-active, push-pull, drdy on int2
- * select 2000dps
- */
- static uint8_t data[] = {0b00001100, 0b0, 0b00001000, 0b00110000};
- const bool ret = twRequest (TWM_WRITE, L3GD20, L3GD20_CTRLREG1, data,
- sizeof (data)/sizeof (*data));
- assert (ret);
+ case START_REQUEST: {
+ /* configuration:
+ * disable power-down-mode, enable z
+ * defaults
+ * high-active, push-pull, drdy on int2
+ * select 2000dps
+ */
+ static uint8_t data[] = {0b00001100, 0b0, 0b00001000, 0b00110000};
+ const bool ret = twRequest (TWM_WRITE, L3GD20, L3GD20_CTRLREG1, data,
+ sizeof (data)/sizeof (*data));
+ if (ret) {
state = STARTING;
}
break;
+ }
case STARTING:
if (shouldWakeup (WAKE_I2C)) {
@@ -105,17 +105,17 @@ bool gyroProcess () {
}
break;
- case STOP_REQUEST:
- if (twr.status == TWST_OK) {
- /* enable power-down mode */
- static uint8_t data[] = {0b00000000};
+ case STOP_REQUEST: {
+ /* enable power-down mode */
+ static uint8_t data[] = {0b00000000};
- const bool ret = twRequest (TWM_WRITE, L3GD20, L3GD20_CTRLREG1, data,
- sizeof (data)/sizeof (*data));
- assert (ret);
+ const bool ret = twRequest (TWM_WRITE, L3GD20, L3GD20_CTRLREG1, data,
+ sizeof (data)/sizeof (*data));
+ if (ret) {
state = STOPPING;
}
break;
+ }
case STOPPING:
if (shouldWakeup (WAKE_I2C)) {
diff --git a/i2c.c b/i2c.c
index bbee35b..54e1f29 100644
--- a/i2c.c
+++ b/i2c.c
@@ -66,11 +66,15 @@ void twInit () {
twr.status = TWST_OK;
}
-/* high-level write
+/* high-level write, returns false if bus is busy
*/
bool twRequest (const twMode mode, const uint8_t address,
const uint8_t subaddress, uint8_t * const data, const uint8_t count) {
- assert (twr.status == TWST_OK);
+ /* busy */
+ if (twr.status != TWST_OK) {
+ return false;
+ }
+
assert (count > 0);
assert (data != NULL);