Libraries
Background
stmI2CIO.c – I2C device functions for STM
Low level functions to effect I2C bus I/O.The channels are by default assigned speeds in order to allow the use of both slow and faster devices:
- channel1: 400 kbit/s
- channel2: 100 kbit/s
These speeds can be changed using i2cInitIO before i2cIO is first called for a channel.
| Functions | |
|---|---|
| i2cInitIO | initialize an I2C channel (hardware interface) |
| i2cIO | I2C general I/O function |
i2cInitIO – initialize an I2C channel (hardware interface)
int i2cInitIO(uint channel, uint hz);
channel – channel number to initialize
hz – speed to run the channel
returns 0 if OK, negative if error
This function is called automatically, with a default speed setting, when i2cIO is called and the channel has not been initialized. Therefore it need only be invoked explicitly for a non-default speed.
i2cIO – I2C general I/O function
int i2cIO(uint device, byte *put, uint putlen, byte *get, uint getlen);
device – channel and physical address of device (channel shifted left 16 bits and ORed with 7-bit or 10-bit I2C physical address); currently only 7-bit addresses are supported
put – start of byte(s) to write
putlen – count of byte(s) to write [may be 0]
get – start of byte(s) to read
getlen – count of byte(s) to read [may be 0]
returns 0 if OK, negative if error
put is ignored if putlen is 0 (NULL recommended). get is ignored if getlen is 0 (NULL recommended).
This function will automatically initialize the appropriate I2C channel when first called for a channel, unless already initialized by an explicit call to i2cInitIO.