Embedded/elua
1
0
Fork 0
mirror of https://github.com/elua/elua.git synced 2025-01-25 01:02:54 +08:00
Code Issues Projects Releases Wiki Activity

Ensure Mizar32 i2c pins are initialized if i2c.setup() is not called

Browse Source
This commit is contained in:
Martin Guy 2012-03-19 12:12:29 +01:00
parent 374a21f15e
commit 8b0bb4bbb9
1 changed files with 19 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
src/platform/avr32/i2c.c
View File

@ -159,11 +159,14 @@ static void ARBITRATION_LOST(void); // Bus control was lost
// ************************
// The bitbanger itself, taken from http://en.wikipedia.org/wiki/I2C
// We don't use GPIO open-drain mode, which is not available on all hardware
// models. Instead, we use two modes to simulate open-drain:
// output of 0 and input.
u32 i2c_setup( u32 speed )
// One-time initialization of the I2C hardware.
// Should be called at all valid initial i2c entry points.
static void i2c_init()
{
static bool i2c_is_initialized = 0;
if( i2c_is_initialized ) return;
// First, set both pins as high-impedance inputs to avoid startup glitches
sda_regs->oderc = SDA_PINMASK;
scl_regs->oderc = SCL_PINMASK;
@ -176,6 +179,16 @@ u32 i2c_setup( u32 speed )
sda_regs->gpers = SDA_PINMASK;
scl_regs->gpers = SCL_PINMASK;
i2c_is_initialized++; // set to true
}
// We don't use GPIO open-drain mode, which is not available on all hardware
// models. Instead, we use two modes to simulate open-drain:
// output of 0 and input.
u32 i2c_setup( u32 speed )
{
i2c_init();
// Limit range to possible values, to avoid divisions by zero below.
if (speed == 0) speed = 1;
if (speed > REQ_CPU_FREQ / 2) speed = REQ_CPU_FREQ / 2;
@ -193,6 +206,8 @@ static int started = 0;
void i2c_start_cond(void)
{
i2c_init();
if (started) {
// if started, do a restart cond
// set SDA to 1