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#![allow(dead_code)]
extern crate stm32f103xx;
use core::cmp::max;
pub const EVENT_MASTER_STARTED: u32 = 0x00030001; /* BUSY, MSL and SB flag */
pub const EVENT_MASTER_TRANSMITTER_MODE_SELECTED: u32 = 0x00070082; /* BUSY, MSL, ADDR, TXE and TRA flags */
pub const EVENT_MASTER_RECEIVER_MODE_SELECTED: u32 = 0x00030002; /* BUSY, MSL and ADDR flags */
pub const EVENT_MASTER_BYTE_RECEIVED: u32 = 0x00030040; /* BUSY, MSL and RXNE flags */
pub const EVENT_MASTER_BYTE_TRANSMITTING: u32 = 0x00070080; /* TRA, BUSY, MSL, TXE flags */
pub const EVENT_MASTER_BYTE_TRANSMITTED: u32 = 0x00070084; /* TRA, BUSY, MSL, TXE and BTF flags */
const FLAGS_MASK: u32 = 0x00ffffff;
const HSI_VALUE: u32 = 8000000;
const HSE_VALUE: u32 = 8000000;
pub struct I2C<'a, 'b> {
i2c: &'a stm32f103xx::i2c1::RegisterBlock,
rcc: &'b stm32f103xx::rcc::RegisterBlock,
}
pub enum TransDir {
TRANSMITTER,
RECEIVER
}
pub enum DutyType {
DUTY0,
DUTY1
}
impl<'a, 'b> I2C<'a, 'b> {
pub fn new(i2c: &'a stm32f103xx::i2c1::RegisterBlock,
rcc: &'b stm32f103xx::rcc::RegisterBlock) -> I2C<'a, 'b> {
I2C{i2c, rcc}
}
fn get_pclk1(&self) -> u32 {
use stm32f103xx::rcc::cfgr::{SWSR, PLLSRCR, PLLXTPRER};
let cfgr = self.rcc.cfgr.read();
let sysclk_freq = match cfgr.sws() {
SWSR::HSI => HSI_VALUE,
SWSR::HSE => HSE_VALUE,
SWSR::PLL => {
let pllmull = cfgr.pllmul().bits();
let pllsource = cfgr.pllsrc();
let pllmull = pllmull as u32 + 2;
match pllsource {
PLLSRCR::INTERNAL => {
(HSI_VALUE >> 1) * pllmull
},
PLLSRCR::EXTERNAL => {
match cfgr.pllxtpre() {
PLLXTPRER::DIV2 => (HSE_VALUE >> 1) * pllmull,
PLLXTPRER::DIV1 => HSE_VALUE * pllmull
}
}
}
}
_ => HSI_VALUE
};
let div_table: [u8; 16] = [0, 0, 0, 0, 1, 2, 3, 4, 1, 2, 3, 4, 6, 7, 8, 9];
let hclk_freq = sysclk_freq >> div_table[cfgr.hpre().bits() as usize];
let pclk1_freq = hclk_freq >> div_table[cfgr.ppre1().bits() as usize];
pclk1_freq
}
/// TODO: support for standard mode
pub fn init(&self,
addr: u8,
scl_freq: u32,
duty_type: DutyType) {
let i2c = &self.i2c;
unsafe {
let pclk1 = self.get_pclk1();
let freq_range: u16 = (pclk1 / 1_000_000) as u16;
self.pe(false);
/* TRISE configuration (in Fm mode, max rise interval is 300) */
i2c.trise.write(|w| w.bits(((freq_range * 300) / 1000 + 1) as u32));
/* CCR configuration */
i2c.ccr.write(|w| match duty_type {
DutyType::DUTY0 => w.ccr().bits(max(pclk1 / (scl_freq * (2 + 1)), 0x1) as u16),
DutyType::DUTY1 => w.ccr().bits(max(pclk1 / (scl_freq * (16 + 9)), 0x1) as u16)
.duty().set_bit(),
}.f_s().set_bit());
self.pe(true); /* PE = 1, enable I2C */
/* CR1 configuration */
i2c.cr1.modify(|r, w| w.bits(r.bits())
.smbus().clear_bit()
.smbtype().clear_bit()
.ack().set_bit());
/* CR2 configuration */
i2c.cr2.modify(|r, w| w.bits(r.bits()).freq().bits(freq_range as u8));
/* OAR1 configuration */
i2c.oar1.write(|w| w.addmode().clear_bit().add7().bits(addr));
while i2c.sr2.read().busy().bit() {} /* wait until the bus is free */
}
}
pub fn pe(&self, enable: bool) {
let i2c = &self.i2c;
unsafe {
match enable {
true => i2c.cr1.modify(|r, w| w.bits(r.bits()).pe().set_bit()),
false => i2c.cr1.modify(|r, w| w.bits(r.bits()).pe().clear_bit())
}
}
}
pub fn start(&self, enable: bool, synced: bool) {
let i2c = &self.i2c;
unsafe {
match enable {
true => i2c.cr1.modify(|r, w| w.bits(r.bits()).start().set_bit()),
false => i2c.cr1.modify(|r, w| w.bits(r.bits()).start().clear_bit())
}
}
if synced {
while !self.check_event(EVENT_MASTER_STARTED) {}
}
}
pub fn stop(&self, enable: bool) {
let i2c = &self.i2c;
unsafe {
match enable {
true => i2c.cr1.modify(|r, w| w.bits(r.bits()).stop().set_bit()),
false => i2c.cr1.modify(|r, w| w.bits(r.bits()).stop().clear_bit())
}
}
}
pub fn conf_ack(&self, enable: bool) {
let i2c = &self.i2c;
unsafe {
match enable {
true => i2c.cr1.modify(|r, w| w.bits(r.bits()).ack().set_bit()),
false => i2c.cr1.modify(|r, w| w.bits(r.bits()).ack().clear_bit())
}
}
}
pub fn send_addr(&self, addr: u8, d: TransDir, synced: bool) {
let addr = (addr << 1) | match d {
TransDir::TRANSMITTER => 0,
TransDir::RECEIVER => 1
};
unsafe {
self.i2c.dr.write(|w| w.dr().bits(addr));
}
if synced {
match d {
TransDir::TRANSMITTER =>
while !self.check_event(EVENT_MASTER_TRANSMITTER_MODE_SELECTED) {},
TransDir::RECEIVER =>
while !self.check_event(EVENT_MASTER_RECEIVER_MODE_SELECTED) {}
}
}
}
pub fn send(&self, data: u8, synced: bool) {
unsafe {
self.i2c.dr.write(|w| w.dr().bits(data));
}
if synced {
while !self.check_event(EVENT_MASTER_BYTE_TRANSMITTED) {}
}
}
pub fn recv(&self, synced: bool) -> u8 {
if synced {
while !self.check_event(EVENT_MASTER_BYTE_RECEIVED) {}
}
self.i2c.dr.read().dr().bits()
}
pub fn check_event(&self, ev_mask: u32) -> bool {
let flags = self.i2c.sr1.read().bits() & 0xffff |
((self.i2c.sr2.read().bits() & 0xffff) << 16) & FLAGS_MASK;
(flags & ev_mask) == ev_mask
}
}
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