Mercurial > ~darius > hgwebdir.cgi > modulator

annotate dac.pio @ 0:a55e39064a71

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
First commit of code that compiles. Does nothing like it should but has cmake goo to wrap dat files
author Daniel O'Connor <darius@dons.net.au>
date Mon, 29 Mar 2021 13:48:34 +1030
parents
children 0d653f60dec8
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
0
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
1 ;
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
2 ; Copyright (c) 2021 Raspberry Pi (Trading) Ltd.
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
3 ;
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
4 ; SPDX-License-Identifier: BSD-3-Clause
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
5 ;
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
6
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
7 .program dac
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
8
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
9 ; Sample bits using an external clock, and push groups of bits into the RX FIFO.
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
10 ; - IN pin 0 is the data pin
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
11 ; - IN pin 1 is the clock pin
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
12 ; - Autopush is enabled, threshold 8
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
13 ;
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
14 ; This program samples data with each rising clock edge (like mode 0 or mode 3
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
15 ; SPI). The data is actually sampled one system clock cycle after the rising
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
16 ; edge is observed, so a clock ratio of at least input_clk < clk_sys / 6 is
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
17 ; recommended for good sampling alignment.
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
18
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
19 wait 0 pin 1
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
20 wait 1 pin 1
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
21 in pins, 1
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
22
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
23 % c-sdk {
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
24 static inline void dac_program_init(PIO pio, uint sm, uint offset, uint pin) {
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
25 pio_sm_config c = dac_program_get_default_config(offset);
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
26
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
27 // Set the IN base pin to the provided `pin` parameter. This is the data
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
28 // pin, and the next-numbered GPIO is used as the clock pin.
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
29 sm_config_set_in_pins(&c, pin);
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
30 // Set the pin directions to input at the PIO
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
31 pio_sm_set_consecutive_pindirs(pio, sm, pin, 2, false);
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
32 // Connect these GPIOs to this PIO block
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
33 pio_gpio_init(pio, pin);
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
34 pio_gpio_init(pio, pin + 1);
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
35
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
36 // Shifting to left matches the customary MSB-first ordering of SPI.
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
37 sm_config_set_in_shift(
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
38 &c,
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
39 false, // Shift-to-right = false (i.e. shift to left)
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
40 true, // Autopush enabled
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
41 8 // Autopush threshold = 8
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
42 );
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
43
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
44 // We only receive, so disable the TX FIFO to make the RX FIFO deeper.
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
45 sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_RX);
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
46
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
47 // Load our configuration, and start the program from the beginning
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
48 pio_sm_init(pio, sm, offset, &c);
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
49 pio_sm_set_enabled(pio, sm, true);
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
50 }
a55e39064a71 First commit of code that compiles.
Daniel O'Connor <darius@dons.net.au>
parents:
diff changeset
51 %}