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|
use embedded_hal::blocking::delay::{DelayMs, DelayUs};
use embedded_hal::digital::v2::OutputPin;
use crate::bus::DataBus;
use crate::error::{Error, Result};
pub struct FourBitBus<
RS: OutputPin,
EN: OutputPin,
D4: OutputPin,
D5: OutputPin,
D6: OutputPin,
D7: OutputPin,
> {
rs: RS,
en: EN,
d4: D4,
d5: D5,
d6: D6,
d7: D7,
}
impl<RS: OutputPin, EN: OutputPin, D4: OutputPin, D5: OutputPin, D6: OutputPin, D7: OutputPin>
FourBitBus<RS, EN, D4, D5, D6, D7>
{
pub fn from_pins(
rs: RS,
en: EN,
d4: D4,
d5: D5,
d6: D6,
d7: D7,
) -> FourBitBus<RS, EN, D4, D5, D6, D7> {
FourBitBus {
rs,
en,
d4,
d5,
d6,
d7,
}
}
fn write_lower_nibble(&mut self, data: u8) -> Result<()> {
let db0: bool = (0b0000_0001 & data) != 0;
let db1: bool = (0b0000_0010 & data) != 0;
let db2: bool = (0b0000_0100 & data) != 0;
let db3: bool = (0b0000_1000 & data) != 0;
if db0 {
self.d4.set_high().map_err(|_| Error)?;
} else {
self.d4.set_low().map_err(|_| Error)?;
}
if db1 {
self.d5.set_high().map_err(|_| Error)?;
} else {
self.d5.set_low().map_err(|_| Error)?;
}
if db2 {
self.d6.set_high().map_err(|_| Error)?;
} else {
self.d6.set_low().map_err(|_| Error)?;
}
if db3 {
self.d7.set_high().map_err(|_| Error)?;
} else {
self.d7.set_low().map_err(|_| Error)?;
}
Ok(())
}
fn write_upper_nibble(&mut self, data: u8) -> Result<()> {
let db4: bool = (0b0001_0000 & data) != 0;
let db5: bool = (0b0010_0000 & data) != 0;
let db6: bool = (0b0100_0000 & data) != 0;
let db7: bool = (0b1000_0000 & data) != 0;
if db4 {
self.d4.set_high().map_err(|_| Error)?;
} else {
self.d4.set_low().map_err(|_| Error)?;
}
if db5 {
self.d5.set_high().map_err(|_| Error)?;
} else {
self.d5.set_low().map_err(|_| Error)?;
}
if db6 {
self.d6.set_high().map_err(|_| Error)?;
} else {
self.d6.set_low().map_err(|_| Error)?;
}
if db7 {
self.d7.set_high().map_err(|_| Error)?;
} else {
self.d7.set_low().map_err(|_| Error)?;
}
Ok(())
}
}
impl<RS: OutputPin, EN: OutputPin, D4: OutputPin, D5: OutputPin, D6: OutputPin, D7: OutputPin>
DataBus for FourBitBus<RS, EN, D4, D5, D6, D7>
{
fn write<D: DelayUs<u16> + DelayMs<u8>>(
&mut self,
byte: u8,
data: bool,
delay: &mut D,
) -> Result<()> {
if data {
self.rs.set_high().map_err(|_| Error)?;
} else {
self.rs.set_low().map_err(|_| Error)?;
}
self.write_upper_nibble(byte)?;
// Pulse the enable pin to recieve the upper nibble
self.en.set_high().map_err(|_| Error)?;
delay.delay_ms(2u8);
self.en.set_low().map_err(|_| Error)?;
self.write_lower_nibble(byte)?;
// Pulse the enable pin to recieve the lower nibble
self.en.set_high().map_err(|_| Error)?;
delay.delay_ms(2u8);
self.en.set_low().map_err(|_| Error)?;
if data {
self.rs.set_low().map_err(|_| Error)?;
}
Ok(())
}
}
|
