Add RMT primitives

lib/rmt.toit

@@ -0,0 +1,281 @@
+// Copyright (C) 2022 Toitware ApS. All rights reserved.
+// Use of this source code is governed by an MIT-style license that can be
+// found in the lib/LICENSE file.
+
+import gpio
+import binary show LITTLE_ENDIAN
+
+/**
+Support for the ESP32 Remote Control (RMT).
+
+A $Channel corresponds to a channel in the ESP32 RMT controller.
+
+$Signals represent a collection of signals to be sent by the RMT controller.
+*/
+
+/**
+A collection of signals to be transferred or received with the RMT controller.
+
+An RMT signal consists of a level (low or high) and a period (the number of
+  ticks the level is sustained).
+
+# Advanced
+The period is specified in number of ticks, so the actual time the level is
+  sustained is determined by the RMT controller configuration.
+
+At the lower level, a signal consits of 16 bits: 15 bits for the period and 1
+  bit for the level. Signals must be transfered as pairs also known as an item.
+*/
+class Signals:
+  /** The number of signals in the collection. */
+  size/int
+
+  bytes_/ByteArray
+
+  /**
+  Creates a collection of signals of the given $size.
+
+  All signals are initialized to 0 period and 0 level.
+
+  # Advanced
+  If the given $size is not divisible by 2, then the byte array allocted for
+    $bytes_ is patted with two bytes to make the $bytes_ usable by the RMT
+    primitives.
+  */
+  constructor .size:
+    bytes_ = ByteArray
+        round_up (size * 2) 4
+
+  /**
+  Creates signals that alternate between a level of 0 and 1 with the periods
+    given in the indexable collection $periods.
+
+  The level of the first signal is $first_level.
+  */
+  constructor.alternating --first_level/int periods:
+    if first_level != 0 and first_level != 1: throw "INVALID_ARGUMENT"
+
+    return Signals.alternating periods.size --first_level=first_level: | idx |
+      periods[idx]
+
+  /**
+  Creates items that alternate between a level of 0 and 1 with the periods
+    given by successive calls to the block.
+
+  The $block is called with the signal index and the level it is created with.
+
+  The level of the first signal is $first_level.
+  */
+  constructor.alternating size/int --first_level [block]:
+    if first_level != 0 and first_level != 1: throw "INVALID_ARGUMENT"
+
+    signals := Signals size
+    level := first_level
+    size.repeat:
+      signals.set_signal it (block.call it level) level
+      level = level ^ 1
+
+    return signals
+
+
+  // TODO what's a nice convenient constructor for populating Signals with known values?
+
+  /**
+  Creates a collection of signals from the given $bytes.
+
+  The $bytes size must be divisible by 4.
+
+  # Advanced
+  The bytes must correspond to bytes produced by the RMT primitives. The
+    primitives operate with pairs of signals (called an item) which  is the
+    reason the $bytes size must be divisible by 4.
+  */
+  constructor.from_bytes bytes/ByteArray:
+    if bytes.size % 4 != 0: throw "INVALID_ARGUMENT"
+
+    bytes_ = bytes
+    size = bytes_.size / 2
+
+  /**
+  Gets the signal period of the $i'th signal.
+
+  The given $i must be in the range [0,$size[.
+  */
+  signal_period i/int -> int:
+    check_bounds_ i
+    return signal_period_ i
+
+  /**
+  Gets the signal level of the $i'th signal.
+
+  The given $i must be in the range [0,$size[.
+  */
+  signal_level i/int -> int:
+    check_bounds_ i
+    return signal_level_ i
+
+  /**
+  Set the $i'th signal to the given $period and $level.
+
+  The given $i must be in the range [0,$size[.
+
+  The given $period must be in the range [0,0x7FFF].
+
+  The given $level must be 0 or 1.
+  */
+  set_signal i/int period/int level/int -> none:
+    check_bounds_ i
+    idx := i * 2
+    if not 0 <= period <= 0x7FFF or level != 0 and level != 1: throw "INVALID_ARGUMENT"
+
+    bytes_[idx] = period & 0xFF
+    bytes_[idx + 1] = (period >> 8 ) | (level << 7)
+
+  /**
+  Invokes the given $block on each signal of this signal collection.
+
+  The block is invoked with the period and the level of each signal.
+  */
+  do [block]:
+    size.repeat:
+      block.call
+        signal_period_ it
+        signal_level_ it
+
+  check_bounds_ i:
+    if not 0 <= i < size: throw "OUT_OF_BOUNDS"
+
+  signal_level_ i -> int:
+    return bytes_[i * 2 + 1] >> 7
+
+  signal_period_ i -> int:
+    idx := i * 2
+    return (LITTLE_ENDIAN.uint16 bytes_ idx) & 0x7fff
+
+/**
+An RMT channel.
+
+The channel must be configured after construction.
+
+The channel can be configured for either RX or TX.
+*/
+class Channel:
+  num/int
+  pin/gpio.Pin
+
+  res_/ByteArray? := null
+
+  /**
+  Constructs a channel using the given $num using the given $pin.
+
+  The givn $num must be in the range [0,7] and must not be in use.
+  */
+  constructor .pin .num:
+    res_ = rmt_use_ resource_group_ num
+
+  /**
+  Configure the channel for RX.
+
+  - $mem_block_num is the number of memory blocks (256 bytes or 128 signals)
+    used by this channel.
+  - $clk_div is the source clock divider. Must be in the range [0,255].
+  - $flags is the configuration flags. See the ESP-IDF documentation for available flags.
+  - $idle_threshold is the number of clock cycles the receiver will run without seeing an edge.
+  - $filter_en is whether the filter is enabled.
+  - $filter_ticks_thresh pulses shorter than this value is filtered away.
+    Only works with $filter_en. The value must be in the range [0,255].
+
+  # Advanced
+  If $mem_block_num is greater than 1, then it will take the memory of the
+    subsequent channels. For instance, if channel 2 is configured with a
+    $mem_block_num = 3, then channels 3 and 4 are unusable.
+  */
+  config_rx
+      --mem_block_num/int=1
+      --clk_div/int=80
+      --flags/int=0
+      --idle_threshold/int=12000
+      --filter_en/bool=true
+      --filter_ticks_thresh/int=100
+      --rx_buffer_size=128:
+    rmt_config_rx_ pin.num num mem_block_num clk_div flags idle_threshold filter_en filter_ticks_thresh rx_buffer_size
+
+  /**
+  Configure the channel for TX.
+
+  - $mem_block_num is the number of memory blocks (256 bytes or 128 signals)
+    used by this channel.
+  - $clk_div is the source clock divider. Must be in the range [0,255].
+  - $flags is the configuration flags. See the ESP-IDF documentation for available flags.
+  - $carrier_en is whether a carrier wave is used.
+  - $carrier_freq_hz is the frequency of the carrier wave.
+  - $carrier_level is the way the carrier way is modulated.
+    Set to 1 to transmit on low output level and 0 to transmit on high output level.
+  - $carrier_duty_percent is the proportion of time the carrier wave is low.
+  - $loop_en is whether the transmitter continously writes the provided signals in a loop.
+  - $idle_output_en is whether the transmitter outputs when idle.
+  - $idle_level is the level transmitted by the transmitter when idle.
+
+  # Advanced
+  If $mem_block_num is greater than 1, then it will take the memory of the
+    subsequent channels. For instance, if channel 2 is configured with a
+    $mem_block_num = 3, then channels 3 and 4 are unusable.
+  */
+  config_tx
+      --mem_block_num/int=1
+      --clk_div/int=80
+      --flags/int=0
+      --carrier_en/bool=false
+      --carrier_freq_hz/int=38000
+      --carrier_level/int=1
+      --carrier_duty_percent/int=33
+      --loop_en/bool=false
+      --idle_output_en/bool=true
+      --idle_level/int=0:
+    rmt_config_tx_ pin.num num mem_block_num clk_div flags carrier_en carrier_freq_hz carrier_level carrier_duty_percent loop_en idle_output_en idle_level
+
+  close:
+    if res_:
+      rmt_unuse_ resource_group_ res_
+      res_ = null
+
+/** Transfers the given $signals over the given $channel.*/
+transfer channel/Channel signals/Signals -> none:
+  rmt_transfer_ channel.num signals.bytes_
+
+/**
+Transfers the given $signals while simultaneously receiving.
+
+The $signals are transferred over the given $tx channel and signals are received on the $rx channel.
+
+The given $max_returned_bytes specifies the maximum byte size of the returned signals.
+*/
+transfer_and_receive --rx/Channel --tx/Channel signals/Signals max_returned_bytes/int -> Signals:
+  result := rmt_transfer_and_read_ tx.num rx.num signals.bytes_ max_returned_bytes
+  return Signals.from_bytes result
+
+resource_group_ ::= rmt_init_
+
+rmt_init_:
+  #primitive.rmt.init
+
+rmt_use_ resource_group channel_num:
+  #primitive.rmt.use
+
+rmt_unuse_ resource_group resource:
+  #primitive.rmt.unuse
+
+rmt_config_rx_ pin_num/int channel_num/int mem_block_num/int clk_div/int flags/int
+    idle_threshold/int filter_en/bool filter_ticks_thresh/int rx_buffer_size/int:
+  #primitive.rmt.config_rx
+
+rmt_config_tx_ pin_num/int channel_num/int mem_block_num/int clk_div/int flags/int
+    carrier_en/bool carrier_freq_hz/int carrier_level/int carrier_duty_percent/int
+    loop_en/bool idle_output_en/bool idle_level/int:
+  #primitive.rmt.config_tx
+
+rmt_transfer_ tx_ch/int signals_bytes/*/Blob*/:
+  #primitive.rmt.transfer
+
+rmt_transfer_and_read_ tx_ch/int rx_ch/int signals_bytes/*/Blob*/ max_output_len/int:
+  #primitive.rmt.transfer_and_read

src/primitive.h

@@ -36,6 +36,7 @@ namespace toit {
   M(i2s,     MODULE_I2S)                     \
   M(spi,     MODULE_SPI)                     \
   M(uart,    MODULE_UART)                    \
+  M(rmt,     MODULE_RMT)                     \
   M(crypto,  MODULE_CRYPTO)                  \
   M(encoding,MODULE_ENCODING)                \
   M(font,    MODULE_FONT)                    \
@@ -369,6 +370,15 @@ namespace toit {
   PRIMITIVE(write, 6)                        \
   PRIMITIVE(read, 1)                         \
 
+#define MODULE_RMT(PRIMITIVE)                \
+  PRIMITIVE(init, 0)                         \
+  PRIMITIVE(use, 2)                          \
+  PRIMITIVE(unuse, 2)                        \
+  PRIMITIVE(config_rx, 9)                    \
+  PRIMITIVE(config_tx, 12)                   \
+  PRIMITIVE(transfer, 2)                     \
+  PRIMITIVE(transfer_and_read, 4)            \
+
 #define MODULE_CRYPTO(PRIMITIVE)             \
   PRIMITIVE(sha1_start, 1)                   \
   PRIMITIVE(sha1_add, 4)                     \
@@ -769,6 +779,7 @@ namespace toit {
 #define _A_T_X509ResourceGroup(N, name)   MAKE_UNPACKING_MACRO(X509ResourceGroup, N, name)
 #define _A_T_PWMResourceGroup(N, name)    MAKE_UNPACKING_MACRO(PWMResourceGroup, N, name)
 #define _A_T_RpcResourceGroup(N, name)    MAKE_UNPACKING_MACRO(RpcResourceGroup, N, name)
+#define _A_T_RMTResourceGroup(N, name)    MAKE_UNPACKING_MACRO(RMTResourceGroup, N, name)
 
 #define _A_T_Resource(N, name)            MAKE_UNPACKING_MACRO(Resource, N, name)
 #define _A_T_Directory(N, name)           MAKE_UNPACKING_MACRO(Directory, N, name)
@@ -896,10 +907,25 @@ namespace toit {
   _A_T_##t10(9, n10); \
   _A_T_##t11(10, n11);
 
-#define _OVERRIDE(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, NAME, ...) NAME
+#define _A_24(t1, n1, t2, n2, t3, n3, t4, n4, t5, n5, t6, n6, t7, n7, t8, n8, t9, n9, t10, n10, t11, n11, t12, n12) \
+  _A_T_##t1(0, n1); \
+  _A_T_##t2(1, n2); \
+  _A_T_##t3(2, n3); \
+  _A_T_##t4(3, n4); \
+  _A_T_##t5(4, n5); \
+  _A_T_##t6(5, n6); \
+  _A_T_##t7(6, n7); \
+  _A_T_##t8(7, n8); \
+  _A_T_##t9(8, n9); \
+  _A_T_##t10(9, n10); \
+  _A_T_##t11(10, n11); \
+  _A_T_##t12(11, n12);
+
+#define _OVERRIDE(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, NAME, ...) NAME
 
 #define ARGS(...)        \
   _OVERRIDE(__VA_ARGS__, \
+    _A_24, _ODD,         \
     _A_22, _ODD,         \
     _A_20, _ODD,         \
     _A_18, _ODD,         \