tmc2208: Initial support for configuring TMC2208 drivers

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

4 files changed, 538 insertions, 1 deletions

diff --git a/config/example-extras.cfg b/config/example-extras.cfg
index c4728457..4559ff72 100644
--- a/config/example-extras.cfg
+++ b/config/example-extras.cfg
@@ -584,6 +584,59 @@
 #   to an appropriate sensitivity value.) The default is to not enable
 #   sensorless homing.
 
+# Configure a TMC2208 (or TMC2224) stepper motor driver via single
+# wire UART. To use this feature, define a config section with a
+# "tmc2208" prefix followed by the name of the corresponding stepper
+# config section (for example, "[tmc2208 stepper_x]").
+#[tmc2208 stepper_x]
+#uart_pin:
+#   The pin connected to the TMC2208 PDN_UART line. This parameter
+#   must be provided.
+#tx_pin:
+#   If using separate receive and transmit lines to communicate with
+#   the driver then set uart_pin to the receive pin and tx_pin to the
+#   transmit pin. The default is to use uart_pin for both reading and
+#   writing.
+#microsteps:
+#   The number of microsteps to configure the driver to use. Valid
+#   values are 1, 2, 4, 8, 16, 32, 64, 128, 256. This parameter must
+#   be provided.
+#interpolate: True
+#   If true, enable step interpolation (the driver will interally step
+#   at a rate of 256 micro-steps). The default is True.
+#run_current:
+#   The amount of current (in amps) to configure the driver to use
+#   during stepper movement. This parameter must be provided.
+#hold_current:
+#   The amount of current (in amps) to configure the driver to use
+#   when the stepper is not moving. The default is to use the same
+#   value as run_current.
+#sense_resistor: 0.110
+#   The resistance (in ohms) of the motor sense resistor. The default
+#   is 0.110 ohms.
+#stealthchop_threshold: 0
+#   The velocity (in mm/s) to set the "stealthChop" threshold to. When
+#   set, "stealthChop" mode will be enabled if the stepper motor
+#   velocity is below this value. The default is 0, which disables
+#   "stealthChop" mode.
+#driver_IHOLDDELAY: 8
+#driver_TPOWERDOWN: 20
+#driver_BLANK_TIME_SELECT: 2
+#driver_TOFF: 3
+#driver_HEND: 0
+#driver_HSTRT: 5
+#driver_PWM_AUTOGRAD: True
+#driver_PWM_AUTOSCALE: True
+#driver_PWM_LIM: 12
+#driver_PWM_REG: 8
+#driver_PWM_FREQ: 1
+#driver_PWM_GRAD: 14
+#driver_PWM_OFS: 36
+#   Set the given register during the configuration of the TMC2208
+#   chip. This may be used to set custom motor parameters. The
+#   defaults for each parameter are next to the parameter name in the
+#   above list.
+
 
 # Homing override. One may use this mechanism to run a series of
 # g-code commands in place of a G28 found in the normal g-code input.
diff --git a/klippy/extras/tmc2208.py b/klippy/extras/tmc2208.py
new file mode 100644
index 00000000..3fa40400
--- /dev/null
+++ b/klippy/extras/tmc2208.py
@@ -0,0 +1,234 @@
+# TMC2208 UART communication and configuration
+#
+# Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import math, logging, collections
+
+TMC_FREQUENCY=12000000.
+GCONF_PDN_DISABLE = 1<<6
+GCONF_MSTEP_REG_SELECT = 1<<7
+GCONF_MULTISTEP_FILT = 1<<8
+
+Registers = {
+    "GCONF": 0x00, "GSTAT": 0x01, "IFCNT": 0x02, "SLAVECONF": 0x03,
+    "OTP_PROG": 0x04, "OTP_READ": 0x05, "IOIN": 0x06, "FACTORY_CONF": 0x07,
+    "IHOLD_IRUN": 0x10, "TPOWERDOWN": 0x11, "TSTEP": 0x12, "TPWMTHRS": 0x13,
+    "VACTUAL": 0x22, "MSCNT": 0x6a, "MSCURACT": 0x6b, "CHOPCONF": 0x6c,
+    "DRV_STATUS": 0x6f, "PWMCONF": 0x70, "PWM_SCALE": 0x71, "PWM_AUTO": 0x72
+}
+
+ReadRegisters = [
+    "GCONF", "GSTAT", "IFCNT", "OTP_READ", "IOIN", "FACTORY_CONF", "TSTEP",
+    "MSCNT", "MSCURACT", "CHOPCONF", "DRV_STATUS",
+    "PWMCONF", "PWM_SCALE", "PWM_AUTO"
+]
+
+
+######################################################################
+# TMC2208 communication
+######################################################################
+
+# Generate a CRC8-ATM value for a bytearray
+def calc_crc8(data):
+    crc = 0
+    for b in data:
+        for i in range(8):
+            if (crc >> 7) ^ (b & 0x01):
+                crc = (crc << 1) ^ 0x07
+            else:
+                crc = (crc << 1)
+            crc &= 0xff
+            b >>= 1
+    return crc
+
+# Add serial start and stop bits to a message in a bytearray
+def add_serial_bits(data):
+    out = 0
+    pos = 0
+    for d in data:
+        b = (d << 1) | 0x200
+        out |= (b << pos)
+        pos += 10
+    res = bytearray()
+    for i in range((pos+7)//8):
+        res.append((out >> (i*8)) & 0xff)
+    return res
+
+# Generate a tmc2208 read register message
+def encode_tmc2208_read(sync, addr, reg):
+    msg = bytearray([sync, addr, reg])
+    msg.append(calc_crc8(msg))
+    return add_serial_bits(msg)
+
+# Generate a tmc2208 write register message
+def encode_tmc2208_write(sync, addr, reg, val):
+    msg = bytearray([sync, addr, reg, (val >> 24) & 0xff, (val >> 16) & 0xff,
+                     (val >> 8) & 0xff, val & 0xff])
+    msg.append(calc_crc8(msg))
+    return add_serial_bits(msg)
+
+# Extract a tmc2208 read response message
+def decode_tmc2208_read(reg, data):
+    # Convert data into a long integer for easy manipulation
+    if len(data) != 10:
+        return None
+    mval = pos = 0
+    for d in bytearray(data):
+        mval |= d << pos
+        pos += 8
+    # Extract register value
+    val = ((((mval >> 31) & 0xff) << 24) | (((mval >> 41) & 0xff) << 16)
+           | (((mval >> 51) & 0xff) << 8) | ((mval >> 61) & 0xff))
+    # Verify start/stop bits and crc
+    encoded_data = encode_tmc2208_write(0x05, 0xff, reg, val)
+    if data != encoded_data:
+        return None
+    return val
+
+
+######################################################################
+# TMC2208 printer object
+######################################################################
+
+class TMC2208:
+    def __init__(self, config):
+        self.printer = config.get_printer()
+        self.name = config.get_name().split()[1]
+        # pin setup
+        ppins = self.printer.lookup_object("pins")
+        rx_pin_params = ppins.lookup_pin(
+            config.get('uart_pin'), can_pullup=True)
+        tx_pin_desc = config.get('tx_pin', None)
+        if tx_pin_desc is None:
+            tx_pin_params = rx_pin_params
+        else:
+            tx_pin_params = ppins.lookup_pin(tx_pin_desc)
+        if rx_pin_params['chip'] is not tx_pin_params['chip']:
+            raise pins.error("TMC2208 rx and tx pins must be on the same mcu")
+        self.mcu = rx_pin_params['chip']
+        self.pullup = rx_pin_params['pullup']
+        self.rx_pin = rx_pin_params['pin']
+        self.tx_pin = tx_pin_params['pin']
+        self.oid = self.mcu.create_oid()
+        self.tmcuart_send_cmd = None
+        self.mcu.add_config_object(self)
+        # Add DUMP_TMC command
+        gcode = self.printer.lookup_object("gcode")
+        gcode.register_mux_command(
+            "DUMP_TMC", "STEPPER", self.name,
+            self.cmd_DUMP_TMC, desc=self.cmd_DUMP_TMC_help)
+        # Get config for initial driver settings
+        run_current = config.getfloat('run_current', above=0., maxval=2.)
+        hold_current = config.getfloat('hold_current', run_current,
+                                       above=0., maxval=2.)
+        sense_resistor = config.getfloat('sense_resistor', 0.110, above=0.)
+        steps = {'256': 0, '128': 1, '64': 2, '32': 3, '16': 4,
+                 '8': 5, '4': 6, '2': 7, '1': 8}
+        self.mres = config.getchoice('microsteps', steps)
+        interpolate = config.getboolean('interpolate', True)
+        sc_velocity = config.getfloat('stealthchop_threshold', 0., minval=0.)
+        sc_threshold = self.velocity_to_clock(config, sc_velocity)
+        iholddelay = config.getint('driver_IHOLDDELAY', 8, minval=0, maxval=15)
+        tpowerdown = config.getint('driver_TPOWERDOWN', 20, minval=0, maxval=255)
+        blank_time_select = config.getint('driver_BLANK_TIME_SELECT', 2,
+                                          minval=0, maxval=3)
+        toff = config.getint('driver_TOFF', 3, minval=1, maxval=15)
+        hend = config.getint('driver_HEND', 0, minval=0, maxval=15)
+        hstrt = config.getint('driver_HSTRT', 5, minval=0, maxval=7)
+        pwm_autograd = config.getboolean('driver_PWM_AUTOGRAD', True)
+        pwm_autoscale = config.getboolean('driver_PWM_AUTOSCALE', True)
+        pwm_lim = config.getint('driver_PWM_LIM', 12, minval=0, maxval=15)
+        pwm_reg = config.getint('driver_PWM_REG', 8, minval=0, maxval=15)
+        pwm_freq = config.getint('driver_PWM_FREQ', 1, minval=0, maxval=3)
+        pwm_grad = config.getint('driver_PWM_GRAD', 14, minval=0, maxval=255)
+        pwm_ofs = config.getint('driver_PWM_OFS', 36, minval=0, maxval=255)
+        # calculate current
+        vsense = False
+        irun = self.current_bits(run_current, sense_resistor, vsense)
+        ihold = self.current_bits(hold_current, sense_resistor, vsense)
+        if irun < 16 and ihold < 16:
+            vsense = True
+            irun = self.current_bits(run_current, sense_resistor, vsense)
+            ihold = self.current_bits(hold_current, sense_resistor, vsense)
+        # Configure registers
+        self.ifcnt = None
+        self.init_regs = collections.OrderedDict()
+        self.init_regs['GCONF'] = (
+            ((sc_velocity == 0.) << 2) | GCONF_PDN_DISABLE
+            | GCONF_MSTEP_REG_SELECT | GCONF_MULTISTEP_FILT)
+        self.init_regs['CHOPCONF'] = (
+            toff | (hstrt << 4) | (hend << 7) | (blank_time_select << 15)
+            | (vsense << 17) | (self.mres << 24) | (interpolate << 28))
+        self.init_regs['IHOLD_IRUN'] = ihold | (irun << 8) | (iholddelay << 16)
+        self.init_regs['TPOWERDOWN'] = tpowerdown
+        self.init_regs['TPWMTHRS'] = max(0, min(0xfffff, sc_threshold))
+        self.init_regs['PWMCONF'] = (
+            pwm_ofs | (pwm_grad << 8) | (pwm_freq << 16)
+            | (pwm_autoscale << 18) | (pwm_autograd << 19)
+            | (pwm_reg << 24) | (pwm_lim << 28))
+    def current_bits(self, current, sense_resistor, vsense_on):
+        sense_resistor += 0.020
+        vsense = 0.32
+        if vsense_on:
+            vsense = 0.18
+        cs = int(32. * current * sense_resistor * math.sqrt(2.) / vsense
+                 - 1. + .5)
+        return max(0, min(31, cs))
+    def velocity_to_clock(self, config, velocity):
+        if not velocity:
+            return 0
+        stepper_name = config.get_name().split()[1]
+        stepper_config = config.getsection(stepper_name)
+        step_dist = stepper_config.getfloat('step_distance')
+        step_dist_256 = step_dist / (1 << self.mres)
+        return int(TMC_FREQUENCY * step_dist_256 / velocity + .5)
+    def build_config(self):
+        bit_ticks = int(self.mcu.get_adjusted_freq() / 9000.)
+        self.mcu.add_config_cmd(
+            "config_tmcuart oid=%d rx_pin=%s pull_up=%d tx_pin=%s bit_time=%d"
+            % (self.oid, self.rx_pin, self.pullup, self.tx_pin, bit_ticks))
+        cmd_queue = self.mcu.alloc_command_queue()
+        self.tmcuart_send_cmd = self.mcu.lookup_command(
+            "tmcuart_send oid=%c write=%*s read=%c", cq=cmd_queue)
+    def printer_state(self, state):
+        if state == 'ready':
+            for reg_name, val in self.init_regs.items():
+                self.set_register(reg_name, val)
+    def get_register(self, reg_name):
+        reg = Registers[reg_name]
+        msg = encode_tmc2208_read(0xf5, 0x00, reg)
+        for retry in range(5):
+            params = self.tmcuart_send_cmd.send_with_response(
+                [self.oid, msg, 10], 'tmcuart_response', self.oid)
+            val = decode_tmc2208_read(reg, params['read'])
+            if val is not None:
+                return val
+        raise self.printer.config_error(
+            "Unable to read tmc2208 '%s' register %s" % (self.name, reg_name))
+    def set_register(self, reg_name, val):
+        msg = encode_tmc2208_write(0xf5, 0x00, Registers[reg_name] | 0x80, val)
+        for retry in range(5):
+            ifcnt = self.ifcnt
+            if ifcnt is None:
+                self.ifcnt = ifcnt = self.get_register("IFCNT")
+            params = self.tmcuart_send_cmd.send_with_response(
+                [self.oid, msg, 0], 'tmcuart_response', self.oid)
+            self.ifcnt = self.get_register("IFCNT")
+            if self.ifcnt == (ifcnt + 1) & 0xff:
+                return
+        raise self.printer.config_error(
+            "Unable to write tmc2208 '%s' register %s" % (self.name, reg_name))
+    cmd_DUMP_TMC_help = "Read and display TMC stepper driver registers"
+    def cmd_DUMP_TMC(self, params):
+        self.printer.lookup_object('toolhead').get_last_move_time()
+        gcode = self.printer.lookup_object('gcode')
+        logging.info("DUMP_TMC %s", self.name)
+        for reg_name in ReadRegisters:
+            val = self.get_register(reg_name)
+            msg = "%-15s %08x" % (reg_name + ":", val)
+            logging.info(msg)
+            gcode.respond_info(msg)
+
+def load_config_prefix(config):
+    return TMC2208(config)
diff --git a/src/Makefile b/src/Makefile
index b59d4ed3..1c6c6760 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -5,4 +5,5 @@ src-$(CONFIG_HAVE_GPIO) += gpiocmds.c stepper.c endstop.c
 src-$(CONFIG_HAVE_GPIO_ADC) += adccmds.c
 src-$(CONFIG_HAVE_GPIO_SPI) += spicmds.c thermocouple.c
 src-$(CONFIG_HAVE_GPIO_HARD_PWM) += pwmcmds.c
-src-$(CONFIG_HAVE_GPIO_BITBANGING) += lcd_st7920.c lcd_hd44780.c buttons.c
+src-$(CONFIG_HAVE_GPIO_BITBANGING) += lcd_st7920.c lcd_hd44780.c buttons.c \
+    tmcuart.c
diff --git a/src/tmcuart.c b/src/tmcuart.c
new file mode 100644
index 00000000..82846b88
--- /dev/null
+++ b/src/tmcuart.c
@@ -0,0 +1,249 @@
+// Commands for sending messages to a TMC2208 via its single wire UART
+//
+// Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include <string.h> // memcpy
+#include "board/gpio.h" // gpio_out_write
+#include "board/irq.h" // irq_disable
+#include "board/misc.h" // timer_read_time
+#include "basecmd.h" // oid_alloc
+#include "command.h" // DECL_COMMAND
+#include "sched.h" // DECL_SHUTDOWN
+
+struct tmcuart_s {
+    struct timer timer;
+    struct gpio_out tx_pin;
+    struct gpio_in rx_pin;
+    uint8_t flags;
+    uint8_t pos, read_count, write_count;
+    uint32_t cfg_bit_time, bit_time;
+    uint8_t data[10];
+};
+
+enum {
+    TU_LINE_HIGH = 1<<0, TU_ACTIVE = 1<<1, TU_READ_SYNC = 1<<2,
+    TU_REPORT = 1<<3, TU_PULLUP = 1<<4, TU_SINGLE_WIRE = 1<<5
+};
+
+static struct task_wake tmcuart_wake;
+
+// Restore uart line to normal "idle" mode
+static void
+tmcuart_reset_line(struct tmcuart_s *t)
+{
+    if (t->flags & TU_SINGLE_WIRE)
+        gpio_out_reset(t->tx_pin, 1);
+    else
+        gpio_out_write(t->tx_pin, 1);
+    t->flags = (t->flags & (TU_PULLUP | TU_SINGLE_WIRE)) | TU_LINE_HIGH;
+}
+
+// Helper function to end a transmission and schedule a response
+static uint_fast8_t
+tmcaurt_finalize(struct tmcuart_s *t)
+{
+    tmcuart_reset_line(t);
+    t->flags |= TU_REPORT;
+    sched_wake_task(&tmcuart_wake);
+    return SF_DONE;
+}
+
+// Event handler for reading uart bits
+static uint_fast8_t
+tmcuart_read_event(struct timer *timer)
+{
+    struct tmcuart_s *t = container_of(timer, struct tmcuart_s, timer);
+    uint8_t v = gpio_in_read(t->rx_pin);
+    // Read and store bit
+    uint8_t pos = t->pos, mask = 1 << (pos & 0x07), data = t->data[pos >> 3];
+    if (v)
+        data |= mask;
+    else
+        data &= ~mask;
+    t->data[pos >> 3] = data;
+    pos++;
+    if (pos >= t->read_count)
+        return tmcaurt_finalize(t);
+    t->pos = pos;
+    t->timer.waketime += t->bit_time;
+    return SF_RESCHEDULE;
+}
+
+// Event handler for detecting start of data reception
+static uint_fast8_t
+tmcuart_read_sync_event(struct timer *timer)
+{
+    struct tmcuart_s *t = container_of(timer, struct tmcuart_s, timer);
+    uint8_t v = gpio_in_read(t->rx_pin);
+    if (v) {
+        t->flags |= TU_READ_SYNC;
+    } else if (t->flags & TU_READ_SYNC) {
+        // Now synchronized - begin reading
+        t->pos = 0;
+        t->timer.func = tmcuart_read_event;
+        return tmcuart_read_event(timer);
+    }
+    if (t->pos++ >= 64) {
+        // Timeout
+        t->read_count = 0;
+        return tmcaurt_finalize(t);
+    }
+    t->timer.waketime += t->bit_time;
+    return SF_RESCHEDULE;
+}
+
+// Event handler called at end of uart writing
+static uint_fast8_t
+tmcuart_send_finish_event(struct timer *timer)
+{
+    struct tmcuart_s *t = container_of(timer, struct tmcuart_s, timer);
+    if (!t->read_count)
+        // This is a tx only operation - success
+        return tmcaurt_finalize(t);
+    // Prepare for message rx
+    if (t->flags & TU_SINGLE_WIRE)
+        gpio_in_reset(t->rx_pin, t->flags & TU_PULLUP);
+    t->pos = 0;
+    t->timer.func = tmcuart_read_sync_event;
+    t->timer.waketime += t->bit_time * 4;
+    return SF_RESCHEDULE;
+}
+
+// Event handler for sending uart bits
+static uint_fast8_t
+tmcuart_send_event(struct timer *timer)
+{
+    struct tmcuart_s *t = container_of(timer, struct tmcuart_s, timer);
+    // Toggle uart output
+    gpio_out_toggle_noirq(t->tx_pin);
+    t->flags ^= TU_LINE_HIGH;
+    // Determine next toggle time
+    uint8_t line_state = t->flags & TU_LINE_HIGH;
+    uint32_t bit_time = t->bit_time, next = bit_time;
+    uint8_t pos = t->pos;
+    for (;;) {
+        pos++;
+        if (pos >= t->write_count) {
+            // No more toggles necessary - schedule finish event
+            t->timer.func = tmcuart_send_finish_event;
+            t->timer.waketime += next;
+            return SF_RESCHEDULE;
+        }
+        uint8_t data = t->data[pos >> 3], bit = (data >> (pos & 0x07)) & 0x01;
+        if (bit != line_state)
+            break;
+        next += bit_time;
+    }
+    t->pos = pos;
+    t->timer.waketime += next;
+    return SF_RESCHEDULE;
+}
+
+// Event handler for sending sync nibble with enhanced baud detection
+static uint_fast8_t
+tmcuart_send_sync_event(struct timer *timer)
+{
+    struct tmcuart_s *t = container_of(timer, struct tmcuart_s, timer);
+    // Toggle uart output and note toggle time
+    gpio_out_toggle_noirq(t->tx_pin);
+    uint32_t cur = timer_read_time();
+    t->flags ^= TU_LINE_HIGH;
+    // Determine next wakeup time
+    t->pos++;
+    if (t->pos == 1) {
+        // First bit just sent - record scheduling offset for later use
+        uint32_t offset = cur - t->timer.waketime;
+        t->bit_time = offset;
+    } else if (t->pos >= 5) {
+        // Last bit of sync nibble just sent - calculate actual baud rate used
+        uint32_t offset = cur - t->timer.waketime, start_offset = t->bit_time;
+        int32_t diff = offset - start_offset;
+        t->bit_time = t->cfg_bit_time + DIV_ROUND_CLOSEST(diff, 4);
+        t->timer.func = tmcuart_send_event;
+        t->timer.waketime += diff + t->bit_time;
+        return SF_RESCHEDULE;
+    }
+    t->timer.waketime += t->cfg_bit_time;
+    return SF_RESCHEDULE;
+}
+
+void
+command_config_tmcuart(uint32_t *args)
+{
+    struct tmcuart_s *t = oid_alloc(args[0], command_config_tmcuart
+                                    , sizeof(*t));
+    uint8_t pull_up = args[2];
+    uint32_t rx_pin = args[1], tx_pin = args[3];
+    t->rx_pin = gpio_in_setup(rx_pin, pull_up);
+    t->tx_pin = gpio_out_setup(tx_pin, 1);
+    t->cfg_bit_time = args[4];
+    t->flags = (TU_LINE_HIGH | (pull_up ? TU_PULLUP : 0)
+                | (rx_pin == tx_pin ? TU_SINGLE_WIRE : 0));
+}
+DECL_COMMAND(command_config_tmcuart,
+             "config_tmcuart oid=%c rx_pin=%u pull_up=%c"
+             " tx_pin=%u bit_time=%u");
+
+// Parse and schedule a TMC UART transmission request
+void
+command_tmcuart_send(uint32_t *args)
+{
+    struct tmcuart_s *t = oid_lookup(args[0], command_config_tmcuart);
+    if (t->flags & TU_ACTIVE)
+        // Uart is busy - silently drop this request (host should retransmit)
+        return;
+    uint8_t write_len = args[1];
+    uint8_t *write = (void*)(size_t)args[2];
+    uint8_t read_len = args[3];
+    if (write_len > sizeof(t->data) || read_len > sizeof(t->data))
+        shutdown("tmcuart data too large");
+    memcpy(t->data, write, write_len);
+    t->pos = 0;
+    t->flags = (t->flags & (TU_LINE_HIGH|TU_PULLUP|TU_SINGLE_WIRE)) | TU_ACTIVE;
+    t->write_count = write_len * 8;
+    t->read_count = read_len * 8;
+    if (write_len >= 1 && (t->data[0] & 0x3f) == 0x2a) {
+        t->timer.func = tmcuart_send_sync_event;
+    } else {
+        t->bit_time = t->cfg_bit_time;
+        t->timer.func = tmcuart_send_event;
+    }
+    irq_disable();
+    t->timer.waketime = timer_read_time() + timer_from_us(200);
+    sched_add_timer(&t->timer);
+    irq_enable();
+}
+DECL_COMMAND(command_tmcuart_send, "tmcuart_send oid=%c write=%*s read=%c");
+
+// Report completed response message back to host
+void
+tmcuart_task(void)
+{
+    if (!sched_check_wake(&tmcuart_wake))
+        return;
+    uint8_t oid;
+    struct tmcuart_s *t;
+    foreach_oid(oid, t, command_config_tmcuart) {
+        if (!(t->flags & TU_REPORT))
+            continue;
+        irq_disable();
+        t->flags &= ~TU_REPORT;
+        irq_enable();
+        sendf("tmcuart_response oid=%c read=%*s"
+              , oid, t->read_count / 8, t->data);
+    }
+}
+DECL_TASK(tmcuart_task);
+
+void
+tmcuart_shutdown(void)
+{
+    uint8_t i;
+    struct tmcuart_s *t;
+    foreach_oid(i, t, command_config_tmcuart) {
+        tmcuart_reset_line(t);
+    }
+}
+DECL_SHUTDOWN(tmcuart_shutdown);