diff --git a/docs/API_Server.md b/docs/API_Server.md
index 562ad57e..8c3e966e 100644
--- a/docs/API_Server.md
+++ b/docs/API_Server.md
@@ -341,6 +341,24 @@ and might later produce asynchronous messages such as:
 The "header" field in the initial query response is used to describe
 the fields found in later "data" responses.
 
+### angle/dump_angle
+
+This endpoint is used to subscribe to
+[angle sensor data](Config_Reference.md#angle). Obtaining these
+low-level motion updates may be useful for diagnostic and debugging
+purposes. Using this endpoint may increase Klipper's system load.
+
+A request may look like:
+`{"id": 123, "method":"angle/dump_angle",
+"params": {"sensor": "my_angle_sensor", "response_template": {}}}`
+and might return:
+`{"id": 123,"result":{"header":["time","angle"]}}`
+and might later produce asynchronous messages such as:
+`{"params":{"errors":0,"data":[[1290.951905,-5063],[1290.952321,-5065]]}}`
+
+The "header" field in the initial query response is used to describe
+the fields found in later "data" responses.
+
 ### pause_resume/cancel
 
 This endpoint is similar to running the "PRINT_CANCEL" G-Code command.
diff --git a/docs/Config_Reference.md b/docs/Config_Reference.md
index a0eecf01..0add9aed 100644
--- a/docs/Config_Reference.md
+++ b/docs/Config_Reference.md
@@ -4001,6 +4001,33 @@ serial:
 #   Auto cancel print when ping varation is above this threshold
 ```
 
+### [angle]
+
+Magnetic hall angle sensor support for reading stepper motor angle
+shaft measurements using a1333, as5047d, or tle5012b SPI chips.  The
+measurements are available via the [API Server](API_Server.md) and
+[motion analysis tool](Debugging.md#motion-analysis-and-data-logging).
+
+```
+[angle my_angle_sensor]
+sensor_type:
+#   The type of the magnetic hall sensor chip. Available choices are
+#   "a1333", "as5047d", and "tle5012b". This parameter must be
+#   specified.
+#sample_period: 0.000400
+#   The query period (in seconds) to use during measurements. The
+#   default is 0.000400 (which is 2500 samples per second).
+cs_pin:
+#   The SPI enable pin for the sensor. This parameter must be provided.
+#spi_speed:
+#spi_bus:
+#spi_software_sclk_pin:
+#spi_software_mosi_pin:
+#spi_software_miso_pin:
+#   See the "common SPI settings" section for a description of the
+#   above parameters.
+```
+
 ## Common bus parameters
 
 ### Common SPI settings
diff --git a/klippy/extras/angle.py b/klippy/extras/angle.py
new file mode 100644
index 00000000..43d4fd1d
--- /dev/null
+++ b/klippy/extras/angle.py
@@ -0,0 +1,188 @@
+# Support for reading SPI magnetic angle sensors
+#
+# Copyright (C) 2021,2022  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import logging, threading
+from . import bus, motion_report
+
+MIN_MSG_TIME = 0.100
+TCODE_ERROR = 0xff
+
+class HelperA1333:
+    SPI_MODE = 3
+    SPI_SPEED = 10000000
+    def __init__(self, config, spi, oid):
+        self.spi = spi
+    def get_static_delay(self):
+        return .000001
+    def start(self):
+        # Setup for angle query
+        self.spi.spi_transfer([0x32, 0x00])
+
+class HelperAS5047D:
+    SPI_MODE = 1
+    SPI_SPEED = int(1. / .000000350)
+    def __init__(self, config, spi, oid):
+        self.spi = spi
+    def get_static_delay(self):
+        return .000100
+    def start(self):
+        # Clear any errors from device
+        self.spi.spi_transfer([0xff, 0xfc]) # Read DIAAGC
+        self.spi.spi_transfer([0x40, 0x01]) # Read ERRFL
+        self.spi.spi_transfer([0xc0, 0x00]) # Read NOP
+
+class HelperTLE5012B:
+    SPI_MODE = 1
+    SPI_SPEED = 4000000
+    def __init__(self, config, spi, oid):
+        self.spi = spi
+    def get_static_delay(self):
+        return .000042700 * 2.5
+    def start(self):
+        # Clear any errors from device
+        self.spi.spi_transfer([0x80, 0x01, 0x00, 0x00, 0x00, 0x00]) # Read STAT
+
+SAMPLE_PERIOD = 0.000400
+
+class Angle:
+    def __init__(self, config):
+        self.printer = config.get_printer()
+        self.sample_period = config.getfloat('sample_period', SAMPLE_PERIOD,
+                                             above=0.)
+        # Measurement conversion
+        self.start_clock = self.time_shift = self.sample_ticks = 0
+        self.last_sequence = self.last_angle = 0
+        # Measurement storage (accessed from background thread)
+        self.lock = threading.Lock()
+        self.raw_samples = []
+        # Sensor type
+        sensors = { "a1333": HelperA1333, "as5047d": HelperAS5047D,
+                    "tle5012b": HelperTLE5012B }
+        sensor_type = config.getchoice('sensor_type', {s: s for s in sensors})
+        sensor_class = sensors[sensor_type]
+        self.spi = bus.MCU_SPI_from_config(config, sensor_class.SPI_MODE,
+                                           default_speed=sensor_class.SPI_SPEED)
+        self.mcu = mcu = self.spi.get_mcu()
+        self.oid = oid = mcu.create_oid()
+        self.sensor_helper = sensor_class(config, self.spi, oid)
+        # Setup mcu sensor_spi_angle bulk query code
+        self.query_spi_angle_cmd = self.query_spi_angle_end_cmd = None
+        mcu.add_config_cmd(
+            "config_spi_angle oid=%d spi_oid=%d spi_angle_type=%s"
+            % (oid, self.spi.get_oid(), sensor_type))
+        mcu.add_config_cmd(
+            "query_spi_angle oid=%d clock=0 rest_ticks=0 time_shift=0"
+            % (oid,), on_restart=True)
+        mcu.register_config_callback(self._build_config)
+        mcu.register_response(self._handle_spi_angle_data,
+                              "spi_angle_data", oid)
+        # API server endpoints
+        self.api_dump = motion_report.APIDumpHelper(
+            self.printer, self._api_update, self._api_startstop, 0.100)
+        self.name = config.get_name().split()[1]
+        wh = self.printer.lookup_object('webhooks')
+        wh.register_mux_endpoint("angle/dump_angle", "sensor", self.name,
+                                 self._handle_dump_angle)
+    def _build_config(self):
+        freq = self.mcu.seconds_to_clock(1.)
+        while float(TCODE_ERROR << self.time_shift) / freq < 0.002:
+            self.time_shift += 1
+        cmdqueue = self.spi.get_command_queue()
+        self.query_spi_angle_cmd = self.mcu.lookup_command(
+            "query_spi_angle oid=%c clock=%u rest_ticks=%u time_shift=%c",
+            cq=cmdqueue)
+        self.query_spi_angle_end_cmd = self.mcu.lookup_query_command(
+            "query_spi_angle oid=%c clock=%u rest_ticks=%u time_shift=%c",
+            "spi_angle_end oid=%c sequence=%hu", oid=self.oid, cq=cmdqueue)
+    # Measurement collection
+    def is_measuring(self):
+        return self.start_clock != 0
+    def _handle_spi_angle_data(self, params):
+        with self.lock:
+            self.raw_samples.append(params)
+    def _extract_samples(self, raw_samples):
+        # Load variables to optimize inner loop below
+        sample_ticks = self.sample_ticks
+        start_clock = self.start_clock
+        clock_to_print_time = self.mcu.clock_to_print_time
+        last_sequence = self.last_sequence
+        last_angle = self.last_angle
+        time_shift = self.time_shift
+        static_delay = self.sensor_helper.get_static_delay()
+        # Process every message in raw_samples
+        count = error_count = 0
+        samples = [None] * (len(raw_samples) * 16)
+        for params in raw_samples:
+            seq = (last_sequence & ~0xffff) | params['sequence']
+            if seq < last_sequence:
+                seq += 0x10000
+            last_sequence = seq
+            d = bytearray(params['data'])
+            msg_mclock = start_clock + seq*16*sample_ticks
+            for i in range(len(d) // 3):
+                tcode = d[i*3]
+                if tcode == TCODE_ERROR:
+                    error_count += 1
+                    continue
+                raw_angle = d[i*3 + 1] | (d[i*3 + 2] << 8)
+                angle_diff = (last_angle - raw_angle) & 0xffff
+                angle_diff -= (angle_diff & 0x8000) << 1
+                last_angle -= angle_diff
+                mclock = msg_mclock + i*sample_ticks + (tcode<<time_shift)
+                ptime = round(clock_to_print_time(mclock) - static_delay, 6)
+                samples[count] = (ptime, last_angle)
+                count += 1
+        self.last_sequence = last_sequence
+        self.last_angle = last_angle
+        del samples[count:]
+        return samples, error_count
+    # API interface
+    def _api_update(self, eventtime):
+        with self.lock:
+            raw_samples = self.raw_samples
+            self.raw_samples = []
+        if not raw_samples:
+            return {}
+        samples, error_count = self._extract_samples(raw_samples)
+        if not samples:
+            return {}
+        return {'data': samples, 'errors': error_count}
+    def _start_measurements(self):
+        if self.is_measuring():
+            return
+        logging.info("Starting angle '%s' measurements", self.name)
+        self.sensor_helper.start()
+        # Start bulk reading
+        with self.lock:
+            self.raw_samples = []
+        self.last_sequence = 0
+        systime = self.printer.get_reactor().monotonic()
+        print_time = self.mcu.estimated_print_time(systime) + MIN_MSG_TIME
+        self.start_clock = reqclock = self.mcu.print_time_to_clock(print_time)
+        rest_ticks = self.mcu.seconds_to_clock(self.sample_period)
+        self.sample_ticks = rest_ticks
+        self.query_spi_angle_cmd.send([self.oid, reqclock, rest_ticks,
+                                       self.time_shift], reqclock=reqclock)
+    def _finish_measurements(self):
+        if not self.is_measuring():
+            return
+        # Halt bulk reading
+        params = self.query_spi_angle_end_cmd.send([self.oid, 0, 0, 0])
+        self.start_clock = 0
+        with self.lock:
+            self.raw_samples = []
+        logging.info("Stopped angle '%s' measurements", self.name)
+    def _api_startstop(self, is_start):
+        if is_start:
+            self._start_measurements()
+        else:
+            self._finish_measurements()
+    def _handle_dump_angle(self, web_request):
+        self.api_dump.add_client(web_request)
+        hdr = ('time', 'angle')
+        web_request.send({'header': hdr})
+
+def load_config_prefix(config):
+    return Angle(config)
diff --git a/src/Makefile b/src/Makefile
index 077e4d26..98c91a30 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -7,6 +7,6 @@ src-$(CONFIG_HAVE_GPIO_ADC) += adccmds.c
 src-$(CONFIG_HAVE_GPIO_SPI) += spicmds.c thermocouple.c
 src-$(CONFIG_HAVE_GPIO_I2C) += i2ccmds.c
 src-$(CONFIG_HAVE_GPIO_HARD_PWM) += pwmcmds.c
-bb-src-$(CONFIG_HAVE_GPIO_SPI) := spi_software.c sensor_adxl345.c
+bb-src-$(CONFIG_HAVE_GPIO_SPI) := spi_software.c sensor_adxl345.c sensor_angle.c
 src-$(CONFIG_HAVE_GPIO_BITBANGING) += $(bb-src-y) lcd_st7920.c lcd_hd44780.c \
     buttons.c tmcuart.c neopixel.c pulse_counter.c
diff --git a/src/sensor_angle.c b/src/sensor_angle.c
new file mode 100644
index 00000000..c03cc957
--- /dev/null
+++ b/src/sensor_angle.c
@@ -0,0 +1,276 @@
+// Support for querying magnetic angle sensors via SPI
+//
+// Copyright (C) 2021  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "basecmd.h" // oid_alloc
+#include "board/misc.h" // timer_read_time
+#include "board/gpio.h" // gpio_out_write
+#include "board/irq.h" // irq_disable
+#include "command.h" // DECL_COMMAND
+#include "sched.h" // DECL_TASK
+#include "spicmds.h" // spidev_transfer
+
+enum { SA_CHIP_A1333, SA_CHIP_AS5047D, SA_CHIP_TLE5012B, SA_CHIP_MAX };
+
+DECL_ENUMERATION("spi_angle_type", "a1333", SA_CHIP_A1333);
+DECL_ENUMERATION("spi_angle_type", "as5047d", SA_CHIP_AS5047D);
+DECL_ENUMERATION("spi_angle_type", "tle5012b", SA_CHIP_TLE5012B);
+
+enum { TCODE_ERROR = 0xff };
+enum {
+    SE_OVERFLOW, SE_SCHEDULE, SE_SPI_TIME, SE_CRC, SE_DUP, SE_NO_ANGLE
+};
+
+#define MAX_SPI_READ_TIME timer_from_us(50)
+
+struct spi_angle {
+    struct timer timer;
+    uint32_t rest_ticks;
+    struct spidev_s *spi;
+    uint16_t sequence;
+    uint8_t flags, chip_type, data_count, time_shift, overflow;
+    uint8_t data[48];
+};
+
+enum {
+    SA_PENDING = 1<<2,
+};
+
+static struct task_wake angle_wake;
+
+// Event handler that wakes spi_angle_task() periodically
+static uint_fast8_t
+angle_event(struct timer *timer)
+{
+    struct spi_angle *sa = container_of(timer, struct spi_angle, timer);
+    uint8_t flags = sa->flags;
+    if (sa->flags & SA_PENDING)
+        sa->overflow++;
+    else
+        sa->flags = flags | SA_PENDING;
+    sched_wake_task(&angle_wake);
+    sa->timer.waketime += sa->rest_ticks;
+    return SF_RESCHEDULE;
+}
+
+void
+command_config_spi_angle(uint32_t *args)
+{
+    uint8_t chip_type = args[2];
+    if (chip_type > SA_CHIP_MAX)
+        shutdown("Invalid spi_angle chip type");
+    struct spi_angle *sa = oid_alloc(args[0], command_config_spi_angle
+                                     , sizeof(*sa));
+    sa->timer.func = angle_event;
+    sa->spi = spidev_oid_lookup(args[1]);
+    if (!spidev_have_cs_pin(sa->spi))
+        shutdown("angle sensor requires cs pin");
+    sa->chip_type = chip_type;
+}
+DECL_COMMAND(command_config_spi_angle,
+             "config_spi_angle oid=%c spi_oid=%c spi_angle_type=%c");
+
+// Report local measurement buffer
+static void
+angle_report(struct spi_angle *sa, uint8_t oid)
+{
+    sendf("spi_angle_data oid=%c sequence=%hu data=%*s"
+          , oid, sa->sequence, sa->data_count, sa->data);
+    sa->data_count = 0;
+    sa->sequence++;
+}
+
+// Send spi_angle_data message if buffer is full
+static void
+angle_check_report(struct spi_angle *sa, uint8_t oid)
+{
+    if (sa->data_count + 3 > ARRAY_SIZE(sa->data))
+        angle_report(sa, oid);
+}
+
+// Add an error indicator to the measurement buffer
+static void
+angle_add_error(struct spi_angle *sa, uint_fast8_t error_code)
+{
+    sa->data[sa->data_count] = TCODE_ERROR;
+    sa->data[sa->data_count + 1] = error_code;
+    sa->data[sa->data_count + 2] = 0;
+    sa->data_count += 3;
+}
+
+// Add a measurement to the buffer
+static void
+angle_add_data(struct spi_angle *sa, uint32_t stime, uint32_t mtime
+               , uint_fast16_t angle)
+{
+    uint32_t tdiff = mtime - stime;
+    if (sa->time_shift)
+        tdiff = (tdiff + (1<<(sa->time_shift - 1))) >> sa->time_shift;
+    if (tdiff >= TCODE_ERROR) {
+        angle_add_error(sa, SE_SCHEDULE);
+        return;
+    }
+    sa->data[sa->data_count] = tdiff;
+    sa->data[sa->data_count + 1] = angle;
+    sa->data[sa->data_count + 2] = angle >> 8;
+    sa->data_count += 3;
+}
+
+// a1333 sensor query
+static void
+a1333_query(struct spi_angle *sa, uint32_t stime)
+{
+    uint8_t msg[2] = { 0x32, 0x00 };
+    uint32_t mtime1 = timer_read_time();
+    spidev_transfer(sa->spi, 1, sizeof(msg), msg);
+    uint32_t mtime2 = timer_read_time();
+    // Data is latched on first sclk edge of response
+    if (mtime2 - mtime1 > MAX_SPI_READ_TIME)
+        angle_add_error(sa, SE_SPI_TIME);
+    else if (msg[0] & 0x80)
+        angle_add_error(sa, SE_CRC);
+    else
+        angle_add_data(sa, stime, mtime1, (msg[0] << 9) | (msg[1] << 1));
+}
+
+// as5047d sensor query
+static void
+as5047d_query(struct spi_angle *sa, uint32_t stime)
+{
+    uint8_t msg[2] = { 0x7F, 0xFE };
+    uint32_t mtime1 = timer_read_time();
+    spidev_transfer(sa->spi, 0, sizeof(msg), msg);
+    uint32_t mtime2 = timer_read_time();
+    // Data is latched on CS pin rising after query request
+    if (mtime2 - mtime1 > MAX_SPI_READ_TIME) {
+        angle_add_error(sa, SE_SPI_TIME);
+        return;
+    }
+    msg[0] = 0xC0;
+    msg[1] = 0x00;
+    spidev_transfer(sa->spi, 1, sizeof(msg), msg);
+    uint_fast8_t parity = msg[0] ^ msg[1];
+    parity ^= parity >> 4;
+    parity ^= parity >> 2;
+    parity ^= parity >> 1;
+    if (parity & 1)
+        angle_add_error(sa, SE_CRC);
+    else if (msg[0] & 0x40)
+        angle_add_error(sa, SE_NO_ANGLE);
+    else
+        angle_add_data(sa, stime, mtime2, (msg[0] << 10) | (msg[1] << 2));
+}
+
+#define TLE_READ 0x80
+#define TLE_READ_LATCH (TLE_READ | 0x04)
+#define TLE_REG_AVAL 0x02
+
+// crc8 "J1850" calculation for tle5012b messages
+static uint8_t
+crc8(uint8_t crc, uint8_t data)
+{
+    crc ^= data;
+    int i;
+    for (i=0; i<8; i++)
+        crc = crc & 0x80 ? (crc << 1) ^ 0x1d : crc << 1;
+    return crc;
+}
+
+// microsecond delay helper
+static inline void
+udelay(uint32_t usecs)
+{
+    uint32_t end = timer_read_time() + timer_from_us(usecs);
+    while (!timer_is_before(end, timer_read_time()))
+        irq_poll();
+}
+
+// tle5012b sensor query
+static void
+tle5012b_query(struct spi_angle *sa, uint32_t stime)
+{
+    struct gpio_out cs_pin = spidev_get_cs_pin(sa->spi);
+    // Latch data (data is latched on rising CS of a NULL message)
+    gpio_out_write(cs_pin, 0);
+    udelay(1);
+    irq_disable();
+    gpio_out_write(cs_pin, 1);
+    uint32_t mtime = timer_read_time();
+    irq_enable();
+
+    uint8_t msg[6] = { TLE_READ_LATCH, (TLE_REG_AVAL << 4) | 0x01, 0, 0, 0, 0 };
+    uint8_t start_crc = 0x3f; // 0x3f == crc8(crc8(0xff, msg[0]), msg[1])
+    spidev_transfer(sa->spi, 1, sizeof(msg), msg);
+    uint8_t crc = ~crc8(crc8(start_crc, msg[2]), msg[3]);
+    if (crc != msg[5])
+        angle_add_error(sa, SE_CRC);
+    else if (!(msg[4] & (1<<4)))
+        angle_add_error(sa, SE_NO_ANGLE);
+    else if (!(msg[2] & 0x80))
+        angle_add_error(sa, SE_DUP);
+    else
+        angle_add_data(sa, stime, mtime, (msg[2] << 9) | (msg[3] << 1));
+}
+
+void
+command_query_spi_angle(uint32_t *args)
+{
+    uint8_t oid = args[0];
+    struct spi_angle *sa = oid_lookup(oid, command_config_spi_angle);
+
+    sched_del_timer(&sa->timer);
+    sa->flags = 0;
+    if (!args[2]) {
+        // End measurements
+        if (sa->data_count)
+            angle_report(sa, oid);
+        sendf("spi_angle_end oid=%c sequence=%hu", oid, sa->sequence);
+        return;
+    }
+    // Start new measurements query
+    sa->timer.waketime = args[1];
+    sa->rest_ticks = args[2];
+    sa->sequence = 0;
+    sa->data_count = 0;
+    sa->time_shift = args[3];
+    sched_add_timer(&sa->timer);
+}
+DECL_COMMAND(command_query_spi_angle,
+             "query_spi_angle oid=%c clock=%u rest_ticks=%u time_shift=%c");
+
+// Background task that performs measurements
+void
+spi_angle_task(void)
+{
+    if (!sched_check_wake(&angle_wake))
+        return;
+    uint8_t oid;
+    struct spi_angle *sa;
+    foreach_oid(oid, sa, command_config_spi_angle) {
+        uint_fast8_t flags = sa->flags;
+        if (!(flags & SA_PENDING))
+            continue;
+        irq_disable();
+        uint32_t stime = sa->timer.waketime;
+        uint_fast8_t overflow = sa->overflow;
+        sa->flags = 0;
+        sa->overflow = 0;
+        irq_enable();
+        stime -= sa->rest_ticks;
+        while (overflow--) {
+            angle_add_error(sa, SE_OVERFLOW);
+            angle_check_report(sa, oid);
+        }
+        uint_fast8_t chip = sa->chip_type;
+        if (chip == SA_CHIP_A1333)
+            a1333_query(sa, stime);
+        else if (chip == SA_CHIP_AS5047D)
+            as5047d_query(sa, stime);
+        else if (chip == SA_CHIP_TLE5012B)
+            tle5012b_query(sa, stime);
+        angle_check_report(sa, oid);
+    }
+}
+DECL_TASK(spi_angle_task);
diff --git a/src/spicmds.c b/src/spicmds.c
index f24bfca3..8bdefbbf 100644
--- a/src/spicmds.c
+++ b/src/spicmds.c
@@ -70,6 +70,18 @@ spidev_set_software_bus(struct spidev_s *spi, struct spi_software *ss)
     spi->flags |= SF_SOFTWARE;
 }
 
+int
+spidev_have_cs_pin(struct spidev_s *spi)
+{
+    return spi->flags & SF_HAVE_PIN;
+}
+
+struct gpio_out
+spidev_get_cs_pin(struct spidev_s *spi)
+{
+    return spi->pin;
+}
+
 void
 spidev_transfer(struct spidev_s *spi, uint8_t receive_data
                 , uint8_t data_len, uint8_t *data)
diff --git a/src/spicmds.h b/src/spicmds.h
index 959fddb9..f7cf83fd 100644
--- a/src/spicmds.h
+++ b/src/spicmds.h
@@ -6,6 +6,8 @@
 struct spidev_s *spidev_oid_lookup(uint8_t oid);
 struct spi_software;
 void spidev_set_software_bus(struct spidev_s *spi, struct spi_software *ss);
+int spidev_have_cs_pin(struct spidev_s *spi);
+struct gpio_out spidev_get_cs_pin(struct spidev_s *spi);
 void spidev_transfer(struct spidev_s *spi, uint8_t receive_data
                      , uint8_t data_len, uint8_t *data);