i2c.c 19.7 KB
Newer Older
1
2
3
#include <stdio.h>
#include <string.h>

4
#include "stm32f4xx_hal.h"
5

6
#include "mpconfig.h"
7
8
9
10
11
#include "nlr.h"
#include "misc.h"
#include "qstr.h"
#include "obj.h"
#include "runtime.h"
12
13
#include "pin.h"
#include "genhdr/pins.h"
14
#include "bufhelper.h"
15
16
#include "i2c.h"

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
/// \moduleref pyb
/// \class I2C - a two-wire serial protocol
///
/// I2C is a two-wire protocol for communicating between devices.  At the physical
/// level it consists of 2 wires: SCL and SDA, the clock and data lines respectively.
///
/// I2C objects are created attached to a specific bus.  They can be initialised
/// when created, or initialised later on:
///
///     from pyb import I2C
///
///     i2c = I2C(1)                         # create on bus 1
///     i2c = I2C(1, I2C.MASTER)             # create and init as a master
///     i2c.init(I2C.MASTER, baudrate=20000) # init as a master
///     i2c.init(I2C.SLAVE, addr=0x42)       # init as a slave with given address
///     i2c.deinit()                         # turn off the peripheral
///
/// Printing the i2c object gives you information about its configuration.
///
/// Basic methods for slave are send and recv:
///
///     i2c.send('abc')      # send 3 bytes
///     i2c.send(0x42)       # send a single byte, given by the number
///     data = i2c.recv(3)   # receive 3 bytes
///
/// To receive inplace, first create a bytearray:
///
///     data = bytearray(3)  # create a buffer
///     i2c.recv(data)       # receive 3 bytes, writing them into data
///
/// You can specify a timeout (in ms):
///
///     i2c.send(b'123', timeout=2000)   # timout after 2 seconds
///
/// A master must specify the recipient's address:
///
///     i2c.init(I2C.MASTER)
///     i2c.send('123', 0x42)        # send 3 bytes to slave with address 0x42
///     i2c.send(b'456', addr=0x42)  # keyword for address
///
/// Master also has other methods:
///
///     i2c.is_ready(0x42)           # check if slave 0x42 is ready
///     i2c.scan()                   # scan for slaves on the bus, returning
///                                  #   a list of valid addresses
///     i2c.mem_read(3, 0x42, 2)     # read 3 bytes from memory of slave 0x42,
///                                  #   starting at address 2 in the slave
///     i2c.mem_write('abc', 0x42, 2, timeout=1000)
65

66
67
68
#define PYB_I2C_MASTER (0)
#define PYB_I2C_SLAVE  (1)

69
#if MICROPY_HW_ENABLE_I2C1
70
I2C_HandleTypeDef I2CHandle1 = {.Instance = NULL};
71
#endif
72
I2C_HandleTypeDef I2CHandle2 = {.Instance = NULL};
73

74
75
void i2c_init0(void) {
    // reset the I2C1 handles
76
#if MICROPY_HW_ENABLE_I2C1
77
78
    memset(&I2CHandle1, 0, sizeof(I2C_HandleTypeDef));
    I2CHandle1.Instance = I2C1;
79
#endif
80
81
    memset(&I2CHandle2, 0, sizeof(I2C_HandleTypeDef));
    I2CHandle2.Instance = I2C2;
82
83
}

84
void i2c_init(I2C_HandleTypeDef *i2c) {
85
    // init the GPIO lines
86
    GPIO_InitTypeDef GPIO_InitStructure;
87
88
89
90
    GPIO_InitStructure.Mode = GPIO_MODE_AF_OD;
    GPIO_InitStructure.Speed = GPIO_SPEED_FAST;
    GPIO_InitStructure.Pull = GPIO_NOPULL; // have external pull-up resistors on both lines

91
    const pin_obj_t *pins[2];
92
    if (0) {
93
#if MICROPY_HW_ENABLE_I2C1
94
    } else if (i2c == &I2CHandle1) {
95
        // X-skin: X9=PB6=SCL, X10=PB7=SDA
96
97
        pins[0] = &pin_B6;
        pins[1] = &pin_B7;
98
99
100
        GPIO_InitStructure.Alternate = GPIO_AF4_I2C1;
        // enable the I2C clock
        __I2C1_CLK_ENABLE();
101
#endif
102
    } else if (i2c == &I2CHandle2) {
103
        // Y-skin: Y9=PB10=SCL, Y10=PB11=SDA
104
105
        pins[0] = &pin_B10;
        pins[1] = &pin_B11;
106
107
108
        GPIO_InitStructure.Alternate = GPIO_AF4_I2C2;
        // enable the I2C clock
        __I2C2_CLK_ENABLE();
109
110
111
    } else {
        // I2C does not exist for this board (shouldn't get here, should be checked by caller)
        return;
112
113
    }

114
115
116
117
118
119
    // init the GPIO lines
    for (uint i = 0; i < 2; i++) {
        GPIO_InitStructure.Pin = pins[i]->pin_mask;
        HAL_GPIO_Init(pins[i]->gpio, &GPIO_InitStructure);
    }

120
    // init the I2C device
121
    if (HAL_I2C_Init(i2c) != HAL_OK) {
122
        // init error
123
124
        // TODO should raise an exception, but this function is not necessarily going to be
        // called via Python, so may not be properly wrapped in an NLR handler
125
        printf("HardwareError: HAL_I2C_Init failed\n");
126
127
128
129
        return;
    }
}

130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
void i2c_deinit(I2C_HandleTypeDef *i2c) {
    HAL_I2C_DeInit(i2c);
    if (0) {
#if MICROPY_HW_ENABLE_I2C1
    } else if (i2c->Instance == I2C1) {
        __I2C1_FORCE_RESET();
        __I2C1_RELEASE_RESET();
        __I2C1_CLK_DISABLE();
#endif
    } else if (i2c->Instance == I2C2) {
        __I2C2_FORCE_RESET();
        __I2C2_RELEASE_RESET();
        __I2C2_CLK_DISABLE();
    }
}

146
147
148
149
150
/******************************************************************************/
/* Micro Python bindings                                                      */

typedef struct _pyb_i2c_obj_t {
    mp_obj_base_t base;
151
    I2C_HandleTypeDef *i2c;
152
153
} pyb_i2c_obj_t;

154
155
STATIC inline bool in_master_mode(pyb_i2c_obj_t *self) { return self->i2c->Init.OwnAddress1 == PYB_I2C_MASTER_ADDRESS; }

156
157
STATIC const pyb_i2c_obj_t pyb_i2c_obj[] = {
#if MICROPY_HW_ENABLE_I2C1
158
    {{&pyb_i2c_type}, &I2CHandle1},
159
160
161
#else
    {{&pyb_i2c_type}, NULL},
#endif
162
163
    {{&pyb_i2c_type}, &I2CHandle2}
};
164

165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
STATIC void pyb_i2c_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
    pyb_i2c_obj_t *self = self_in;

    uint i2c_num;
    if (self->i2c->Instance == I2C1) { i2c_num = 1; }
    else { i2c_num = 2; }

    if (self->i2c->State == HAL_I2C_STATE_RESET) {
        print(env, "I2C(%u)", i2c_num);
    } else {
        if (in_master_mode(self)) {
            print(env, "I2C(%u, I2C.MASTER, baudrate=%u)", i2c_num, self->i2c->Init.ClockSpeed);
        } else {
            print(env, "I2C(%u, I2C.SLAVE, addr=0x%02x)", i2c_num, (self->i2c->Instance->OAR1 >> 1) & 0x7f);
        }
    }
}

183
184
185
186
187
188
189
190
/// \method init(mode, *, addr=0x12, baudrate=400000, gencall=False)
///
/// Initialise the I2C bus with the given parameters:
///
///   - `mode` must be either `I2C.MASTER` or `I2C.SLAVE`
///   - `addr` is the 7-bit address (only sensible for a slave)
///   - `baudrate` is the SCL clock rate (only sensible for a master)
///   - `gencall` is whether to support general call mode
191
192
193
194
195
STATIC const mp_arg_t pyb_i2c_init_args[] = {
    { MP_QSTR_mode,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
    { MP_QSTR_addr,     MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0x12} },
    { MP_QSTR_baudrate, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 400000} },
    { MP_QSTR_gencall,  MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
196
};
197
#define PYB_I2C_INIT_NUM_ARGS ARRAY_SIZE(pyb_i2c_init_args)
198
199
200

STATIC mp_obj_t pyb_i2c_init_helper(const pyb_i2c_obj_t *self, uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    // parse args
201
202
    mp_arg_val_t vals[PYB_I2C_INIT_NUM_ARGS];
    mp_arg_parse_all(n_args, args, kw_args, PYB_I2C_INIT_NUM_ARGS, pyb_i2c_init_args, vals);
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

    // set the I2C configuration values
    I2C_InitTypeDef *init = &self->i2c->Init;

    if (vals[0].u_int == PYB_I2C_MASTER) {
        // use a special address to indicate we are a master
        init->OwnAddress1 = PYB_I2C_MASTER_ADDRESS;
    } else {
        init->OwnAddress1 = (vals[1].u_int << 1) & 0xfe;
    }

    init->AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
    init->ClockSpeed      = MIN(vals[2].u_int, 400000);
    init->DualAddressMode = I2C_DUALADDRESS_DISABLED;
    init->DutyCycle       = I2C_DUTYCYCLE_16_9;
    init->GeneralCallMode = vals[3].u_bool ? I2C_GENERALCALL_ENABLED : I2C_GENERALCALL_DISABLED;
    init->NoStretchMode   = I2C_NOSTRETCH_DISABLED;
    init->OwnAddress2     = 0xfe; // unused

    // init the I2C bus
    i2c_init(self->i2c);

    return mp_const_none;
}

228
229
230
231
232
233
234
/// \classmethod \constructor(bus, ...)
///
/// Construct an I2C object on the given bus.  `bus` can be 1 or 2.
/// With no additional parameters, the I2C object is created but not
/// initialised (it has the settings from the last initialisation of
/// the bus, if any).  If extra arguments are given, the bus is initialised.
/// See `init` for parameters of initialisation.
235
236
STATIC mp_obj_t pyb_i2c_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
    // check arguments
237
    mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
238
239
240
241
242

    // get i2c number
    machine_int_t i2c_id = mp_obj_get_int(args[0]) - 1;

    // check i2c number
243
    if (!(0 <= i2c_id && i2c_id < ARRAY_SIZE(pyb_i2c_obj) && pyb_i2c_obj[i2c_id].i2c != NULL)) {
244
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "I2C bus %d does not exist", i2c_id + 1));
245
246
    }

247
    // get I2C object
248
    const pyb_i2c_obj_t *i2c_obj = &pyb_i2c_obj[i2c_id];
249

250
251
252
253
254
255
    if (n_args > 1 || n_kw > 0) {
        // start the peripheral
        mp_map_t kw_args;
        mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
        pyb_i2c_init_helper(i2c_obj, n_args - 1, args + 1, &kw_args);
    }
256

257
    return (mp_obj_t)i2c_obj;
258
259
}

260
261
262
263
264
STATIC mp_obj_t pyb_i2c_init(uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    return pyb_i2c_init_helper(args[0], n_args - 1, args + 1, kw_args);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_i2c_init_obj, 1, pyb_i2c_init);

265
266
/// \method deinit()
/// Turn off the I2C bus.
267
268
269
270
271
272
273
STATIC mp_obj_t pyb_i2c_deinit(mp_obj_t self_in) {
    pyb_i2c_obj_t *self = self_in;
    i2c_deinit(self->i2c);
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_i2c_deinit_obj, pyb_i2c_deinit);

274
275
/// \method is_ready(addr)
/// Check if an I2C device responds to the given address.  Only valid when in master mode.
276
277
STATIC mp_obj_t pyb_i2c_is_ready(mp_obj_t self_in, mp_obj_t i2c_addr_o) {
    pyb_i2c_obj_t *self = self_in;
278
279
280
281
282

    if (!in_master_mode(self)) {
        nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "I2C must be a master"));
    }

283
284
285
    machine_uint_t i2c_addr = mp_obj_get_int(i2c_addr_o) << 1;

    for (int i = 0; i < 10; i++) {
286
        HAL_StatusTypeDef status = HAL_I2C_IsDeviceReady(self->i2c, i2c_addr, 10, 200);
287
288
289
290
291
292
293
294
295
        if (status == HAL_OK) {
            return mp_const_true;
        }
    }

    return mp_const_false;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(pyb_i2c_is_ready_obj, pyb_i2c_is_ready);

296
297
298
/// \method scan()
/// Scan all I2C addresses from 0x01 to 0x7f and return a list of those that respond.
/// Only valid when in master mode.
299
300
301
STATIC mp_obj_t pyb_i2c_scan(mp_obj_t self_in) {
    pyb_i2c_obj_t *self = self_in;

302
303
304
305
    if (!in_master_mode(self)) {
        nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "I2C must be a master"));
    }

306
307
308
309
    mp_obj_t list = mp_obj_new_list(0, NULL);

    for (uint addr = 1; addr <= 127; addr++) {
        for (int i = 0; i < 10; i++) {
310
            HAL_StatusTypeDef status = HAL_I2C_IsDeviceReady(self->i2c, addr << 1, 10, 200);
311
312
313
314
315
316
317
318
319
320
321
            if (status == HAL_OK) {
                mp_obj_list_append(list, mp_obj_new_int(addr));
                break;
            }
        }
    }

    return list;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_i2c_scan_obj, pyb_i2c_scan);

322
323
324
325
326
327
328
329
/// \method send(send, addr=0x00, timeout=5000)
/// Send data on the bus:
///
///   - `send` is the data to send (an integer to send, or a buffer object)
///   - `addr` is the address to send to (only required in master mode)
///   - `timeout` is the timeout in milliseconds to wait for the send
///
/// Return value: `None`.
330
331
332
333
STATIC const mp_arg_t pyb_i2c_send_args[] = {
    { MP_QSTR_send,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
    { MP_QSTR_addr,    MP_ARG_INT, {.u_int = PYB_I2C_MASTER_ADDRESS} },
    { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 5000} },
334
};
335
#define PYB_I2C_SEND_NUM_ARGS ARRAY_SIZE(pyb_i2c_send_args)
336

337
338
339
340
STATIC mp_obj_t pyb_i2c_send(uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    pyb_i2c_obj_t *self = args[0];

    // parse args
341
342
    mp_arg_val_t vals[PYB_I2C_SEND_NUM_ARGS];
    mp_arg_parse_all(n_args - 1, args + 1, kw_args, PYB_I2C_SEND_NUM_ARGS, pyb_i2c_send_args, vals);
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359

    // get the buffer to send from
    mp_buffer_info_t bufinfo;
    uint8_t data[1];
    pyb_buf_get_for_send(vals[0].u_obj, &bufinfo, data);

    // send the data
    HAL_StatusTypeDef status;
    if (in_master_mode(self)) {
        if (vals[1].u_int == PYB_I2C_MASTER_ADDRESS) {
            nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "addr argument required"));
        }
        machine_uint_t i2c_addr = vals[1].u_int << 1;
        status = HAL_I2C_Master_Transmit(self->i2c, i2c_addr, bufinfo.buf, bufinfo.len, vals[2].u_int);
    } else {
        status = HAL_I2C_Slave_Transmit(self->i2c, bufinfo.buf, bufinfo.len, vals[2].u_int);
    }
360
361
362

    if (status != HAL_OK) {
        // TODO really need a HardwareError object, or something
363
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_Exception, "HAL_I2C_xxx_Transmit failed with code %d", status));
364
365
    }

366
    return mp_const_none;
367
}
368
369
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_i2c_send_obj, 1, pyb_i2c_send);

370
371
372
373
374
375
376
377
378
379
380
/// \method recv(send, addr=0x00, timeout=5000)
///
/// Receive data on the bus:
///
///   - `recv` can be an integer, which is the number of bytes to receive,
///     or a mutable buffer, which will be filled with received bytes
///   - `addr` is the address to receive from (only required in master mode)
///   - `timeout` is the timeout in milliseconds to wait for the receive
///
/// Return value: if `recv` is an integer then a new buffer of the bytes received,
/// otherwise the same buffer that was passed in to `recv`.
381
382
383
384
STATIC const mp_arg_t pyb_i2c_recv_args[] = {
    { MP_QSTR_recv,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
    { MP_QSTR_addr,    MP_ARG_INT, {.u_int = PYB_I2C_MASTER_ADDRESS} },
    { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 5000} },
385
};
386
#define PYB_I2C_RECV_NUM_ARGS ARRAY_SIZE(pyb_i2c_recv_args)
387

388
389
STATIC mp_obj_t pyb_i2c_recv(uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    pyb_i2c_obj_t *self = args[0];
390

391
    // parse args
392
393
    mp_arg_val_t vals[PYB_I2C_RECV_NUM_ARGS];
    mp_arg_parse_all(n_args - 1, args + 1, kw_args, PYB_I2C_RECV_NUM_ARGS, pyb_i2c_recv_args, vals);
394
395
396
397
398
399

    // get the buffer to receive into
    mp_buffer_info_t bufinfo;
    mp_obj_t o_ret = pyb_buf_get_for_recv(vals[0].u_obj, &bufinfo);

    // receive the data
400
    HAL_StatusTypeDef status;
401
402
403
404
405
406
    if (in_master_mode(self)) {
        if (vals[1].u_int == PYB_I2C_MASTER_ADDRESS) {
            nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "addr argument required"));
        }
        machine_uint_t i2c_addr = vals[1].u_int << 1;
        status = HAL_I2C_Master_Receive(self->i2c, i2c_addr, bufinfo.buf, bufinfo.len, vals[2].u_int);
407
    } else {
408
        status = HAL_I2C_Slave_Receive(self->i2c, bufinfo.buf, bufinfo.len, vals[2].u_int);
409
410
411
412
    }

    if (status != HAL_OK) {
        // TODO really need a HardwareError object, or something
413
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_Exception, "HAL_I2C_xxx_Receive failed with code %d", status));
414
415
    }

416
417
418
419
420
421
    // return the received data
    if (o_ret == MP_OBJ_NULL) {
        return vals[0].u_obj;
    } else {
        return mp_obj_str_builder_end(o_ret);
    }
422
}
423
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_i2c_recv_obj, 1, pyb_i2c_recv);
424

425
426
427
428
429
430
431
432
433
434
435
/// \method mem_read(data, addr, memaddr, timeout=5000)
///
/// Read from the memory of an I2C device:
///
///   - `data` can be an integer or a buffer to read into
///   - `addr` is the I2C device address
///   - `memaddr` is the memory location within the I2C device
///   - `timeout` is the timeout in milliseconds to wait for the read
///
/// Returns the read data.
/// This is only valid in master mode.
436
437
438
439
440
STATIC const mp_arg_t pyb_i2c_mem_read_args[] = {
    { MP_QSTR_data,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
    { MP_QSTR_addr,    MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
    { MP_QSTR_memaddr, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
    { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 5000} },
441
};
442
#define PYB_I2C_MEM_READ_NUM_ARGS ARRAY_SIZE(pyb_i2c_mem_read_args)
443

444
STATIC mp_obj_t pyb_i2c_mem_read(uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
445
446
    pyb_i2c_obj_t *self = args[0];

447
448
449
450
451
    if (!in_master_mode(self)) {
        nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "I2C must be a master"));
    }

    // parse args
452
453
    mp_arg_val_t vals[PYB_I2C_MEM_READ_NUM_ARGS];
    mp_arg_parse_all(n_args - 1, args + 1, kw_args, PYB_I2C_MEM_READ_NUM_ARGS, pyb_i2c_mem_read_args, vals);
454
455
456
457

    // get the buffer to read into
    mp_buffer_info_t bufinfo;
    mp_obj_t o_ret = pyb_buf_get_for_recv(vals[0].u_obj, &bufinfo);
458

459
460
461
462
463
    // get the addresses
    machine_uint_t i2c_addr = vals[1].u_int << 1;
    machine_uint_t mem_addr = vals[2].u_int;

    HAL_StatusTypeDef status = HAL_I2C_Mem_Read(self->i2c, i2c_addr, mem_addr, I2C_MEMADD_SIZE_8BIT, bufinfo.buf, bufinfo.len, vals[3].u_int);
464
465
466

    if (status != HAL_OK) {
        // TODO really need a HardwareError object, or something
467
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_Exception, "HAL_I2C_Mem_Read failed with code %d", status));
468
469
    }

470
471
472
473
474
475
    // return the read data
    if (o_ret == MP_OBJ_NULL) {
        return vals[0].u_obj;
    } else {
        return mp_obj_str_builder_end(o_ret);
    }
476
}
477
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_i2c_mem_read_obj, 1, pyb_i2c_mem_read);
478

479
480
481
482
483
484
485
486
487
488
489
/// \method mem_write(data, addr, memaddr, timeout=5000)
///
/// Write to the memory of an I2C device:
///
///   - `data` can be an integer or a buffer to write from
///   - `addr` is the I2C device address
///   - `memaddr` is the memory location within the I2C device
///   - `timeout` is the timeout in milliseconds to wait for the write
///
/// Returns `None`.
/// This is only valid in master mode.
490
STATIC mp_obj_t pyb_i2c_mem_write(uint n_args, const mp_obj_t *args, mp_map_t *kw_args) {
491
    pyb_i2c_obj_t *self = args[0];
492
493
494

    if (!in_master_mode(self)) {
        nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "I2C must be a master"));
495
496
    }

497
    // parse args (same as mem_read)
498
499
    mp_arg_val_t vals[PYB_I2C_MEM_READ_NUM_ARGS];
    mp_arg_parse_all(n_args - 1, args + 1, kw_args, PYB_I2C_MEM_READ_NUM_ARGS, pyb_i2c_mem_read_args, vals);
500
501
502
503
504
505
506
507
508
509
510

    // get the buffer to write from
    mp_buffer_info_t bufinfo;
    uint8_t data[1];
    pyb_buf_get_for_send(vals[0].u_obj, &bufinfo, data);

    // get the addresses
    machine_uint_t i2c_addr = vals[1].u_int << 1;
    machine_uint_t mem_addr = vals[2].u_int;

    HAL_StatusTypeDef status = HAL_I2C_Mem_Write(self->i2c, i2c_addr, mem_addr, I2C_MEMADD_SIZE_8BIT, bufinfo.buf, bufinfo.len, vals[3].u_int);
511
512
513

    if (status != HAL_OK) {
        // TODO really need a HardwareError object, or something
514
        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_Exception, "HAL_I2C_Mem_Write failed with code %d", status));
515
516
517
518
    }

    return mp_const_none;
}
519
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(pyb_i2c_mem_write_obj, 1, pyb_i2c_mem_write);
520

521
STATIC const mp_map_elem_t pyb_i2c_locals_dict_table[] = {
522
523
524
    // instance methods
    { MP_OBJ_NEW_QSTR(MP_QSTR_init), (mp_obj_t)&pyb_i2c_init_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_deinit), (mp_obj_t)&pyb_i2c_deinit_obj },
525
    { MP_OBJ_NEW_QSTR(MP_QSTR_is_ready), (mp_obj_t)&pyb_i2c_is_ready_obj },
526
    { MP_OBJ_NEW_QSTR(MP_QSTR_scan), (mp_obj_t)&pyb_i2c_scan_obj },
527
528
    { MP_OBJ_NEW_QSTR(MP_QSTR_send), (mp_obj_t)&pyb_i2c_send_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_recv), (mp_obj_t)&pyb_i2c_recv_obj },
529
530
    { MP_OBJ_NEW_QSTR(MP_QSTR_mem_read), (mp_obj_t)&pyb_i2c_mem_read_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_mem_write), (mp_obj_t)&pyb_i2c_mem_write_obj },
531
532

    // class constants
533
534
    /// \constant MASTER - for initialising the bus to master mode
    /// \constant SLAVE - for initialising the bus to slave mode
535
536
    { MP_OBJ_NEW_QSTR(MP_QSTR_MASTER),       MP_OBJ_NEW_SMALL_INT(PYB_I2C_MASTER) },
    { MP_OBJ_NEW_QSTR(MP_QSTR_SLAVE),        MP_OBJ_NEW_SMALL_INT(PYB_I2C_SLAVE) },
537
538
};

539
540
STATIC MP_DEFINE_CONST_DICT(pyb_i2c_locals_dict, pyb_i2c_locals_dict_table);

541
542
543
const mp_obj_type_t pyb_i2c_type = {
    { &mp_type_type },
    .name = MP_QSTR_I2C,
544
    .print = pyb_i2c_print,
545
    .make_new = pyb_i2c_make_new,
546
    .locals_dict = (mp_obj_t)&pyb_i2c_locals_dict,
547
};