Commit 6ce64d8e authored by Dominic Clifton's avatar Dominic Clifton
Browse files

Fix STM32F3Discovery ACC sensor reads. Fixes #384.

parent d5b44f69
......@@ -38,6 +38,31 @@
#define LSM303DLHC_ACCEL_ADDRESS 0x19
#define LSM303DLHC_MAG_ADDRESS 0x1E
/**
* Address Auto Increment - See LSM303DLHC datasheet, Section 5.1.1 I2C operation.
* http://www.st.com/web/en/resource/technical/document/datasheet/DM00027543.pdf
*
* "The I2C embedded inside the LSM303DLHC behaves like a slave device and the following protocol must be adhered to.
* After the START condition (ST) a slave address is sent, once a slave acknowledge (SAK) has been returned, an 8-bit
* sub-address (SUB) is transmitted; the 7 LSBs represent the actual register address while the MSB enables address
* autoincrement.
*
* If the MSB of the SUB field is ‘1’, the SUB (register address) is automatically increased to allow multiple data
* Read/Write.
*
* To minimize the communication between the master and magnetic digital interface of LSM303DLHC, the address pointer
* updates automatically without master intervention. This automatic address pointer update has two additional
* features. First, when address 12 or higher is accessed, the pointer updates to address 00, and secondly, when
* address 08 is reached, the pointer rolls back to address 03. Logically, the address pointer operation functions
* as shown below.
* 1) If (address pointer = 08) then the address pointer = 03
* Or else, if (address pointer >= 12) then the address pointer = 0
* Or else, (address pointer) = (address pointer) + 1
*
* The address pointer value itself cannot be read via the I2C bus"
*/
#define AUTO_INCREMENT_ENABLE 0x80
// Registers
#define CTRL_REG1_A 0x20
......@@ -110,7 +135,7 @@ static void lsm303dlhcAccRead(int16_t *gyroADC)
{
uint8_t buf[6];
bool ok = i2cRead(LSM303DLHC_ACCEL_ADDRESS, OUT_X_L_A, 6, buf);
bool ok = i2cRead(LSM303DLHC_ACCEL_ADDRESS, AUTO_INCREMENT_ENABLE | OUT_X_L_A, 6, buf);
if (!ok)
return;
......
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