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dhylandsdpgeorge
dhylands
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dpgeorge
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stmhal: Enable I2C support for F7 MCUs.
1 parent 26664dd commit 34fe5a3

5 files changed

Lines changed: 83 additions & 12 deletions

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‎stmhal/boards/STM32F7DISC/mpconfigboard.h‎

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -47,6 +47,19 @@ void STM32F7DISC_board_early_init(void);
4747
#define MICROPY_HW_I2C1_SCL (pin_B8)
4848
#define MICROPY_HW_I2C1_SDA (pin_B9)
4949

50+
#define MICROPY_HW_I2C3_SCL (pin_H7)
51+
#define MICROPY_HW_I2C3_SDA (pin_H8)
52+
53+
// The STM32F7 uses a TIMINGR register which is configured using an Excel
54+
// Spreadsheet from AN4235: http://www.st.com/web/en/catalog/tools/PF258335
55+
// We use an array of baudrates and corresponding TIMINGR values.
56+
//
57+
// The value 0x40912732 was obtained from the DISCOVERY_I2Cx_TIMING constant
58+
// defined in the STM32F7Cube file Drivers/BSP/STM32F746G-Discovery/stm32f7456g_discovery.h
59+
#define MICROPY_HW_I2C_BAUDRATE_TIMING {{100000, 0x40912732}}
60+
#define MICROPY_HW_I2C_BAUDRATE_DEFAULT 100000
61+
#define MICROPY_HW_I2C_BAUDRATE_MAX 100000
62+
5063
// USRSW is pulled low. Pressing the button makes the input go high.
5164
#define MICROPY_HW_USRSW_PIN (pin_I11)
5265
#define MICROPY_HW_USRSW_PULL (GPIO_NOPULL)

‎stmhal/boards/STM32F7DISC/pins.csv‎

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -26,12 +26,16 @@ TP1,PH2
2626
TP2,PI8
2727
TP3,PH15
2828
AUDIO_INT,PD6
29+
AUDIO_SDA,PH8
30+
AUDIO_SCL,PH7
2931
EXT_SDA,PB9
3032
EXT_SCL,PB8
3133
EXT_RST,PG3
3234
SD_SW,PC13
3335
LCD_BL_CTRL,PK3
3436
LCD_INT,PI13
37+
LCD_SDA,PH8
38+
LCD_SCL,PH7
3539
OTG_FS_POWER,PD5
3640
OTG_FS_OVER_CURRENT,PD4
3741
OTG_HS_OVER_CURRENT,PE3

‎stmhal/i2c.c‎

Lines changed: 64 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -37,9 +37,21 @@
3737
#include "i2c.h"
3838
#include MICROPY_HAL_H
3939

40-
#if !defined(STM32F7)
41-
// The STM32F7 has Timing, where the F4 has ClockSpeed and DutyCycle, so we
42-
// need to figure that out before we can enable i2c
40+
#if !defined(MICROPY_HW_I2C_BAUDRATE_DEFAULT)
41+
#define MICROPY_HW_I2C_BAUDRATE_DEFAULT 400000
42+
#endif
43+
44+
#if !defined(MICROPY_HW_I2C_BAUDRATE_MAX)
45+
#define MICROPY_HW_I2C_BAUDRATE_MAX 400000
46+
#endif
47+
48+
#if !defined(I2C_NOSTRETCH_DISABLE)
49+
// Assumes that the F7 firmware is newer, so the F4 firmware will eventually
50+
// catchup. I2C_NOSTRETCH_DISABLED was renamed to I2C_NOSTRETCH_DISABLE
51+
// in the F7 so we use the F7 constant and provide a backwards compatabilty
52+
// #define here.
53+
#define I2C_NOSTRETCH_DISABLE I2C_NOSTRETCH_DISABLED
54+
#endif
4355

4456
/// \moduleref pyb
4557
/// \class I2C - a two-wire serial protocol
@@ -138,6 +150,50 @@ STATIC const pyb_i2c_obj_t pyb_i2c_obj[] = {
138150
#endif
139151
};
140152

153+
#if defined(MICROPY_HW_I2C_BAUDRATE_TIMING)
154+
// The STM32F0, F3, and F7 use a TIMINGR register rather than ClockSpeed and
155+
// DutyCycle.
156+
157+
STATIC const struct {
158+
uint32_t baudrate;
159+
uint32_t timing;
160+
} pyb_i2c_baudrate_timing[] = MICROPY_HW_I2C_BAUDRATE_TIMING;
161+
162+
#define NUM_BAUDRATE_TIMINGS MP_ARRAY_SIZE(pyb_i2c_baudrate_timing)
163+
164+
STATIC void i2c_set_baudrate(I2C_InitTypeDef *init, uint32_t baudrate) {
165+
for (int i = 0; i < NUM_BAUDRATE_TIMINGS; i++) {
166+
if (pyb_i2c_baudrate_timing[i].baudrate == baudrate) {
167+
init->Timing = pyb_i2c_baudrate_timing[i].timing;
168+
return;
169+
}
170+
}
171+
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
172+
"Unsupported I2C baudrate: %lu", baudrate));
173+
}
174+
175+
STATIC uint32_t i2c_get_baudrate(I2C_InitTypeDef *init) {
176+
for (int i = 0; i < NUM_BAUDRATE_TIMINGS; i++) {
177+
if (pyb_i2c_baudrate_timing[i].timing == init->Timing) {
178+
return pyb_i2c_baudrate_timing[i].baudrate;
179+
}
180+
}
181+
return 0;
182+
}
183+
184+
#else
185+
186+
STATIC void i2c_set_baudrate(I2C_InitTypeDef *init, uint32_t baudrate) {
187+
init->ClockSpeed = baudrate;
188+
init->DutyCycle = I2C_DUTYCYCLE_16_9;
189+
}
190+
191+
STATIC uint32_t i2c_get_baudrate(I2C_InitTypeDef *init) {
192+
return init->ClockSpeed;
193+
}
194+
195+
#endif // MICROPY_HW_I2C_BAUDRATE_TIMING
196+
141197
void i2c_init0(void) {
142198
// reset the I2C1 handles
143199
#if defined(MICROPY_HW_I2C1_SCL)
@@ -276,7 +332,7 @@ STATIC void pyb_i2c_print(const mp_print_t *print, mp_obj_t self_in, mp_print_ki
276332
mp_printf(print, "I2C(%u)", i2c_num);
277333
} else {
278334
if (in_master_mode(self)) {
279-
mp_printf(print, "I2C(%u, I2C.MASTER, baudrate=%u)", i2c_num, self->i2c->Init.ClockSpeed);
335+
mp_printf(print, "I2C(%u, I2C.MASTER, baudrate=%u)", i2c_num, i2c_get_baudrate(&self->i2c->Init));
280336
} else {
281337
mp_printf(print, "I2C(%u, I2C.SLAVE, addr=0x%02x)", i2c_num, (self->i2c->Instance->OAR1 >> 1) & 0x7f);
282338
}
@@ -295,7 +351,7 @@ STATIC mp_obj_t pyb_i2c_init_helper(const pyb_i2c_obj_t *self, mp_uint_t n_args,
295351
static const mp_arg_t allowed_args[] = {
296352
{ MP_QSTR_mode, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
297353
{ MP_QSTR_addr, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0x12} },
298-
{ MP_QSTR_baudrate, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 400000} },
354+
{ MP_QSTR_baudrate, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = MICROPY_HW_I2C_BAUDRATE_DEFAULT} },
299355
{ MP_QSTR_gencall, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
300356
};
301357

@@ -313,13 +369,13 @@ STATIC mp_obj_t pyb_i2c_init_helper(const pyb_i2c_obj_t *self, mp_uint_t n_args,
313369
init->OwnAddress1 = (args[1].u_int << 1) & 0xfe;
314370
}
315371

372+
i2c_set_baudrate(init, MIN(args[2].u_int, MICROPY_HW_I2C_BAUDRATE_MAX));
316373
init->AddressingMode = I2C_ADDRESSINGMODE_7BIT;
317-
init->ClockSpeed = MIN(args[2].u_int, 400000);
318374
init->DualAddressMode = I2C_DUALADDRESS_DISABLED;
319-
init->DutyCycle = I2C_DUTYCYCLE_16_9;
320375
init->GeneralCallMode = args[3].u_bool ? I2C_GENERALCALL_ENABLED : I2C_GENERALCALL_DISABLED;
321376
init->NoStretchMode = I2C_NOSTRETCH_DISABLED;
322-
init->OwnAddress2 = 0xfe; // unused
377+
init->OwnAddress2 = 0; // unused
378+
init->NoStretchMode = I2C_NOSTRETCH_DISABLE;
323379

324380
// init the I2C bus
325381
i2c_init(self->i2c);
@@ -753,5 +809,3 @@ const mp_obj_type_t pyb_i2c_type = {
753809
.make_new = pyb_i2c_make_new,
754810
.locals_dict = (mp_obj_t)&pyb_i2c_locals_dict,
755811
};
756-
757-
#endif // STM32F7

‎stmhal/main.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -471,8 +471,8 @@ int main(void) {
471471
rng_init0();
472472
#endif
473473

474-
#if !defined(STM32F7) // Temp hack
475474
i2c_init0();
475+
#if !defined(STM32F7) // Temp hack
476476
spi_init0();
477477
#endif
478478
pyb_usb_init0();

‎stmhal/modpyb.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -589,8 +589,8 @@ STATIC const mp_map_elem_t pyb_module_globals_table[] = {
589589
#if defined(MICROPY_HW_LED1)
590590
{ MP_OBJ_NEW_QSTR(MP_QSTR_LED), (mp_obj_t)&pyb_led_type },
591591
#endif
592-
#if !defined(STM32F7) // Temp hack
593592
{ MP_OBJ_NEW_QSTR(MP_QSTR_I2C), (mp_obj_t)&pyb_i2c_type },
593+
#if !defined(STM32F7) // Temp hack
594594
{ MP_OBJ_NEW_QSTR(MP_QSTR_SPI), (mp_obj_t)&pyb_spi_type },
595595
#endif
596596
{ MP_OBJ_NEW_QSTR(MP_QSTR_UART), (mp_obj_t)&pyb_uart_type },

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