/
wrpll.rs
310 lines (269 loc) · 9.78 KB
/
wrpll.rs
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
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
use board_misoc::{csr, clock};
mod i2c {
use board_misoc::{csr, clock};
#[derive(Debug, Clone, Copy)]
pub enum Dcxo {
Main,
Helper
}
fn half_period() { clock::spin_us(10) }
const SDA_MASK: u8 = 2;
const SCL_MASK: u8 = 1;
fn sda_i(dcxo: Dcxo) -> bool {
let reg = match dcxo {
Dcxo::Main => unsafe { csr::wrpll::main_dcxo_gpio_in_read() },
Dcxo::Helper => unsafe { csr::wrpll::helper_dcxo_gpio_in_read() },
};
reg & SDA_MASK != 0
}
fn sda_oe(dcxo: Dcxo, oe: bool) {
let reg = match dcxo {
Dcxo::Main => unsafe { csr::wrpll::main_dcxo_gpio_oe_read() },
Dcxo::Helper => unsafe { csr::wrpll::helper_dcxo_gpio_oe_read() },
};
let reg = if oe { reg | SDA_MASK } else { reg & !SDA_MASK };
match dcxo {
Dcxo::Main => unsafe { csr::wrpll::main_dcxo_gpio_oe_write(reg) },
Dcxo::Helper => unsafe { csr::wrpll::helper_dcxo_gpio_oe_write(reg) }
}
}
fn sda_o(dcxo: Dcxo, o: bool) {
let reg = match dcxo {
Dcxo::Main => unsafe { csr::wrpll::main_dcxo_gpio_out_read() },
Dcxo::Helper => unsafe { csr::wrpll::helper_dcxo_gpio_out_read() },
};
let reg = if o { reg | SDA_MASK } else { reg & !SDA_MASK };
match dcxo {
Dcxo::Main => unsafe { csr::wrpll::main_dcxo_gpio_out_write(reg) },
Dcxo::Helper => unsafe { csr::wrpll::helper_dcxo_gpio_out_write(reg) }
}
}
fn scl_oe(dcxo: Dcxo, oe: bool) {
let reg = match dcxo {
Dcxo::Main => unsafe { csr::wrpll::main_dcxo_gpio_oe_read() },
Dcxo::Helper => unsafe { csr::wrpll::helper_dcxo_gpio_oe_read() },
};
let reg = if oe { reg | SCL_MASK } else { reg & !SCL_MASK };
match dcxo {
Dcxo::Main => unsafe { csr::wrpll::main_dcxo_gpio_oe_write(reg) },
Dcxo::Helper => unsafe { csr::wrpll::helper_dcxo_gpio_oe_write(reg) }
}
}
fn scl_o(dcxo: Dcxo, o: bool) {
let reg = match dcxo {
Dcxo::Main => unsafe { csr::wrpll::main_dcxo_gpio_out_read() },
Dcxo::Helper => unsafe { csr::wrpll::helper_dcxo_gpio_out_read() },
};
let reg = if o { reg | SCL_MASK } else { reg & !SCL_MASK };
match dcxo {
Dcxo::Main => unsafe { csr::wrpll::main_dcxo_gpio_out_write(reg) },
Dcxo::Helper => unsafe { csr::wrpll::helper_dcxo_gpio_out_write(reg) }
}
}
pub fn init(dcxo: Dcxo) -> Result<(), &'static str> {
// Set SCL as output, and high level
scl_o(dcxo, true);
scl_oe(dcxo, true);
// Prepare a zero level on SDA so that sda_oe pulls it down
sda_o(dcxo, false);
// Release SDA
sda_oe(dcxo, false);
// Check the I2C bus is ready
half_period();
half_period();
if !sda_i(dcxo) {
// Try toggling SCL a few times
for _bit in 0..8 {
scl_o(dcxo, false);
half_period();
scl_o(dcxo, true);
half_period();
}
}
if !sda_i(dcxo) {
return Err("SDA is stuck low and doesn't get unstuck");
}
Ok(())
}
pub fn start(dcxo: Dcxo) {
// Set SCL high then SDA low
scl_o(dcxo, true);
half_period();
sda_oe(dcxo, true);
half_period();
}
pub fn stop(dcxo: Dcxo) {
// First, make sure SCL is low, so that the target releases the SDA line
scl_o(dcxo, false);
half_period();
// Set SCL high then SDA high
sda_oe(dcxo, true);
scl_o(dcxo, true);
half_period();
sda_oe(dcxo, false);
half_period();
}
pub fn write(dcxo: Dcxo, data: u8) -> bool {
// MSB first
for bit in (0..8).rev() {
// Set SCL low and set our bit on SDA
scl_o(dcxo, false);
sda_oe(dcxo, data & (1 << bit) == 0);
half_period();
// Set SCL high ; data is shifted on the rising edge of SCL
scl_o(dcxo, true);
half_period();
}
// Check ack
// Set SCL low, then release SDA so that the I2C target can respond
scl_o(dcxo, false);
half_period();
sda_oe(dcxo, false);
// Set SCL high and check for ack
scl_o(dcxo, true);
half_period();
// returns true if acked (I2C target pulled SDA low)
!sda_i(dcxo)
}
pub fn read(dcxo: Dcxo, ack: bool) -> u8 {
// Set SCL low first, otherwise setting SDA as input may cause a transition
// on SDA with SCL high which will be interpreted as START/STOP condition.
scl_o(dcxo, false);
half_period(); // make sure SCL has settled low
sda_oe(dcxo, false);
let mut data: u8 = 0;
// MSB first
for bit in (0..8).rev() {
scl_o(dcxo, false);
half_period();
// Set SCL high and shift data
scl_o(dcxo, true);
half_period();
if sda_i(dcxo) { data |= 1 << bit }
}
// Send ack
// Set SCL low and pull SDA low when acking
scl_o(dcxo, false);
if ack { sda_oe(dcxo, true) }
half_period();
// then set SCL high
scl_o(dcxo, true);
half_period();
data
}
}
mod si549 {
use board_misoc::clock;
use super::i2c;
const ADDRESS: u8 = 0x55;
pub fn write(dcxo: i2c::Dcxo, reg: u8, val: u8) -> Result<(), &'static str> {
i2c::start(dcxo);
if !i2c::write(dcxo, ADDRESS << 1) {
return Err("Si549 failed to ack write address")
}
if !i2c::write(dcxo, reg) {
return Err("Si549 failed to ack register")
}
if !i2c::write(dcxo, val) {
return Err("Si549 failed to ack value")
}
i2c::stop(dcxo);
Ok(())
}
pub fn write_no_ack_value(dcxo: i2c::Dcxo, reg: u8, val: u8) -> Result<(), &'static str> {
i2c::start(dcxo);
if !i2c::write(dcxo, ADDRESS << 1) {
return Err("Si549 failed to ack write address")
}
if !i2c::write(dcxo, reg) {
return Err("Si549 failed to ack register")
}
i2c::write(dcxo, val);
i2c::stop(dcxo);
Ok(())
}
pub fn read(dcxo: i2c::Dcxo, reg: u8) -> Result<u8, &'static str> {
i2c::start(dcxo);
if !i2c::write(dcxo, ADDRESS << 1) {
return Err("Si549 failed to ack write address")
}
if !i2c::write(dcxo, reg) {
return Err("Si549 failed to ack register")
}
i2c::stop(dcxo);
i2c::start(dcxo);
if !i2c::write(dcxo, (ADDRESS << 1) | 1) {
return Err("Si549 failed to ack read address")
}
let val = i2c::read(dcxo, false);
i2c::stop(dcxo);
Ok(val)
}
pub fn program(dcxo: i2c::Dcxo, hsdiv: u16, lsdiv: u8, fbdiv: u64) -> Result<(), &'static str> {
i2c::init(dcxo)?;
write(dcxo, 255, 0x00)?; // PAGE
write_no_ack_value(dcxo, 7, 0x80)?; // RESET
clock::spin_us(100_000); // required? not specified in datasheet.
write(dcxo, 255, 0x00)?; // PAGE
write(dcxo, 69, 0x00)?; // Disable FCAL override.
// Note: Value 0x00 from Table 5.6 is inconsistent with Table 5.7,
// which shows bit 0 as reserved and =1.
write(dcxo, 17, 0x00)?; // Synchronously disable output
// The Si549 has no ID register, so we check that it responds correctly
// by writing values to a RAM-like register and reading them back.
for test_value in 0..255 {
write(dcxo, 23, test_value)?;
let readback = read(dcxo, 23)?;
if readback != test_value {
return Err("Si549 detection failed");
}
}
write(dcxo, 23, hsdiv as u8)?;
write(dcxo, 24, (hsdiv >> 8) as u8 | (lsdiv << 4))?;
write(dcxo, 26, fbdiv as u8)?;
write(dcxo, 27, (fbdiv >> 8) as u8)?;
write(dcxo, 28, (fbdiv >> 16) as u8)?;
write(dcxo, 29, (fbdiv >> 24) as u8)?;
write(dcxo, 30, (fbdiv >> 32) as u8)?;
write(dcxo, 31, (fbdiv >> 40) as u8)?;
write(dcxo, 7, 0x08)?; // Start FCAL
write(dcxo, 17, 0x01)?; // Synchronously enable output
Ok(())
}
}
fn get_helper_frequency() -> u32 {
unsafe { csr::wrpll::helper_frequency_start_write(1); }
clock::spin_us(10_000);
unsafe { csr::wrpll::helper_frequency_stop_write(1); }
clock::spin_us(1);
unsafe { csr::wrpll::helper_frequency_counter_read() }
}
pub fn init() {
info!("initializing...");
unsafe { csr::wrpll::helper_reset_write(1); }
#[cfg(rtio_frequency = "125.0")]
let (m_hsdiv, m_lsdiv, m_fbdiv) = (0x017, 2, 0x04b5badb98a);
#[cfg(rtio_frequency = "125.0")]
let (h_hsdiv, h_lsdiv, h_fbdiv) = (0x017, 2, 0x04b5c447213);
si549::program(i2c::Dcxo::Main, m_hsdiv, m_lsdiv, m_fbdiv)
.expect("cannot initialize main Si549");
si549::program(i2c::Dcxo::Helper, h_hsdiv, h_lsdiv, h_fbdiv)
.expect("cannot initialize helper Si549");
// Si549 Settling Time for Large Frequency Change.
// Datasheet said 10ms but it lied.
clock::spin_us(50_000);
unsafe { csr::wrpll::helper_reset_write(0); }
clock::spin_us(1);
info!("helper clock frequency: {}MHz", get_helper_frequency()/10000);
info!("DDMTD test:");
for _ in 0..20 {
unsafe {
csr::wrpll::ddmtd_main_arm_write(1);
while csr::wrpll::ddmtd_main_arm_read() != 0 {}
info!("{}", csr::wrpll::ddmtd_main_tag_read());
}
}
}
pub fn select_recovered_clock(rc: bool) {
info!("select_recovered_clock: {}", rc);
}