Commit 34f01c2c authored by Damien George's avatar Damien George
Browse files

stmhal: Add some documentation to I2C, SPI and USART modules.

parent 0ae21a81
......@@ -14,6 +14,51 @@
#include "bufhelper.h"
#include "i2c.h"
// Usage model:
//
// 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.deinit() # turn off the peripheral
// i2c.init(I2C.MASTER, baudrate=20000) # init as a master
// i2c.init(I2C.SLAVE, addr=0x42) # init as a slave with given address
//
// 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)
#define PYB_I2C_MASTER (0)
#define PYB_I2C_SLAVE (1)
......
......@@ -14,6 +14,25 @@
#include "bufhelper.h"
#include "spi.h"
// Usage model:
//
// See usage model of I2C in i2c.c. SPI is very similar. Main difference is
// parameters to init the SPI bus:
//
// from pyb import SPI
// spi = SPI(1, SPI.MASTER, baudrate=600000, polarity=1, phase=1, crc=0x7)
//
// Only required parameter is mode, SPI.MASTER or SPI.SLAVE. Polarity can be
// 0 or 1, and is the level the idle clock line sits at. Phase can be 1 or 2
// for number of edges. Crc can be None for no CRC, or a polynomial specifier.
//
// Additional method for SPI:
//
// data = spi.send_recv(b'1234') # send 4 bytes and receive 4 bytes
// buf = bytearray(4)
// spi.send_recv(b'1234', buf) # send 4 bytes and receive 4 into buf
// spi.send_recv(buf, buf) # send/recv 4 bytes from/to buf
#if MICROPY_HW_ENABLE_SPI1
SPI_HandleTypeDef SPIHandle1 = {.Instance = NULL};
#endif
......@@ -384,6 +403,9 @@ STATIC mp_obj_t pyb_spi_send_recv(uint n_args, const mp_obj_t *args, mp_map_t *k
} else {
// recv argument given
mp_get_buffer_raise(vals[1].u_obj, &bufinfo_recv, MP_BUFFER_WRITE);
if (bufinfo_recv.len != bufinfo_send.len) {
nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "recv must be same length as send"));
}
o_ret = MP_OBJ_NULL;
}
}
......
......@@ -12,6 +12,21 @@
#include "bufhelper.h"
#include "usart.h"
// Usage model:
//
// See usage model of I2C in i2c.c. USART is very similar. Main difference is
// parameters to init the USART bus:
//
// from pyb import USART
// usart = USART(1, 9600) # init with given baudrate
// usart.init(9600, bits=8, stop=1, parity=None) # init with given parameters
//
// Bits can be 8 or 9, stop can be 1 or 2, parity can be None, 0 (even), 1 (odd).
//
// Extra method:
//
// usart.any() # returns True if any characters waiting
struct _pyb_usart_obj_t {
mp_obj_base_t base;
pyb_usart_t usart_id;
......
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