1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
use crate::traits::Command;
use core::marker::PhantomData;
use embedded_hal::{
blocking::{delay::*, spi::Write},
digital::v2::*,
};
/// The Connection Interface of all (?) Waveshare EPD-Devices
///
pub(crate) struct DisplayInterface<SPI, CS, BUSY, DC, RST> {
/// SPI
_spi: PhantomData<SPI>,
/// CS for SPI
cs: CS,
/// Low for busy, Wait until display is ready!
busy: BUSY,
/// Data/Command Control Pin (High for data, Low for command)
dc: DC,
/// Pin for Reseting
rst: RST,
}
impl<SPI, CS, BUSY, DC, RST> DisplayInterface<SPI, CS, BUSY, DC, RST>
where
SPI: Write<u8>,
CS: OutputPin,
BUSY: InputPin,
DC: OutputPin,
RST: OutputPin,
{
pub fn new(cs: CS, busy: BUSY, dc: DC, rst: RST) -> Self {
DisplayInterface {
_spi: PhantomData::default(),
cs,
busy,
dc,
rst,
}
}
/// Basic function for sending [Commands](Command).
///
/// Enables direct interaction with the device with the help of [data()](DisplayInterface::data())
pub(crate) fn cmd<T: Command>(&mut self, spi: &mut SPI, command: T) -> Result<(), SPI::Error> {
// low for commands
let _ = self.dc.set_low();
// Transfer the command over spi
self.write(spi, &[command.address()])
}
/// Basic function for sending an array of u8-values of data over spi
///
/// Enables direct interaction with the device with the help of [command()](EPD4in2::command())
pub(crate) fn data(&mut self, spi: &mut SPI, data: &[u8]) -> Result<(), SPI::Error> {
// high for data
let _ = self.dc.set_high();
// Transfer data (u8-array) over spi
self.write(spi, data)
}
/// Basic function for sending [Commands](Command) and the data belonging to it.
///
/// TODO: directly use ::write? cs wouldn't needed to be changed twice than
pub(crate) fn cmd_with_data<T: Command>(
&mut self,
spi: &mut SPI,
command: T,
data: &[u8],
) -> Result<(), SPI::Error> {
self.cmd(spi, command)?;
self.data(spi, data)
}
/// Basic function for sending the same byte of data (one u8) multiple times over spi
///
/// Enables direct interaction with the device with the help of [command()](ConnectionInterface::command())
pub(crate) fn data_x_times(
&mut self,
spi: &mut SPI,
val: u8,
repetitions: u32,
) -> Result<(), SPI::Error> {
// high for data
let _ = self.dc.set_high();
// Transfer data (u8) over spi
for _ in 0..repetitions {
self.write(spi, &[val])?;
}
Ok(())
}
// spi write helper/abstraction function
fn write(&mut self, spi: &mut SPI, data: &[u8]) -> Result<(), SPI::Error> {
// activate spi with cs low
let _ = self.cs.set_low();
// transfer spi data
// Be careful!! Linux has a default limit of 4096 bytes per spi transfer
// see https://raspberrypi.stackexchange.com/questions/65595/spi-transfer-fails-with-buffer-size-greater-than-4096
if cfg!(target_os = "linux") {
for data_chunk in data.chunks(4096) {
spi.write(data_chunk)?;
}
} else {
spi.write(data)?;
}
// deativate spi with cs high
let _ = self.cs.set_high();
Ok(())
}
/// Waits until device isn't busy anymore (busy == HIGH)
///
/// This is normally handled by the more complicated commands themselves,
/// but in the case you send data and commands directly you might need to check
/// if the device is still busy
///
/// is_busy_low
///
/// - TRUE for epd4in2, epd2in13, epd2in7, epd5in83, epd7in5
/// - FALSE for epd2in9, epd1in54 (for all Display Type A ones?)
///
/// Most likely there was a mistake with the 2in9 busy connection
/// //TODO: use the #cfg feature to make this compile the right way for the certain types
pub(crate) fn wait_until_idle(&mut self, is_busy_low: bool) {
//tested: worked without the delay for all tested devices
//self.delay_ms(1);
while self.is_busy(is_busy_low) {
//tested: REMOVAL of DELAY: it's only waiting for the signal anyway and should continue work asap
//old: shorten the time? it was 100 in the beginning
//self.delay_ms(5);
}
}
/// Checks if device is still busy
///
/// This is normally handled by the more complicated commands themselves,
/// but in the case you send data and commands directly you might need to check
/// if the device is still busy
///
/// is_busy_low
///
/// - TRUE for epd4in2, epd2in13, epd2in7, epd5in83, epd7in5
/// - FALSE for epd2in9, epd1in54 (for all Display Type A ones?)
///
/// Most likely there was a mistake with the 2in9 busy connection
/// //TODO: use the #cfg feature to make this compile the right way for the certain types
pub(crate) fn is_busy(&self, is_busy_low: bool) -> bool {
(is_busy_low && self.busy.is_low().unwrap_or(false))
|| (!is_busy_low && self.busy.is_high().unwrap_or(false))
}
/// Resets the device.
///
/// Often used to awake the module from deep sleep. See [EPD4in2::sleep()](EPD4in2::sleep())
///
/// TODO: Takes at least 400ms of delay alone, can it be shortened?
pub(crate) fn reset<DELAY: DelayMs<u8>>(&mut self, delay: &mut DELAY) {
let _ = self.rst.set_low();
//TODO: why 200ms? (besides being in the arduino version)
delay.delay_ms(200);
let _ = self.rst.set_high();
//TODO: same as 3 lines above
delay.delay_ms(200);
}
}