1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
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
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
.. _zephyr_quickref:
Quick reference for the Zephyr port
===================================
Below is a quick reference for the Zephyr port. If it is your first time working with this port please consider reading the following sections first:
.. toctree::
:maxdepth: 1
general.rst
tutorial/index.rst
Running MicroPython
-------------------
See the corresponding section of the tutorial: :ref:`intro`.
Delay and timing
----------------
Use the :mod:`time <time>` module::
import time
time.sleep(1) # sleep for 1 second
time.sleep_ms(500) # sleep for 500 milliseconds
time.sleep_us(10) # sleep for 10 microseconds
start = time.ticks_ms() # get millisecond counter
delta = time.ticks_diff(time.ticks_ms(), start) # compute time difference
Pins and GPIO
-------------
Use the :ref:`machine.Pin <machine.Pin>` class::
from machine import Pin
pin = Pin(("gpiob", 21), Pin.IN) # create input pin on GPIO port B
print(pin) # print pin port and number
pin.init(Pin.OUT, Pin.PULL_UP, value=1) # reinitialize pin
pin.value(1) # set pin to high
pin.value(0) # set pin to low
pin.on() # set pin to high
pin.off() # set pin to low
pin = Pin(("gpiob", 21), Pin.IN) # create input pin on GPIO port B
pin = Pin(("gpiob", 21), Pin.OUT, value=1) # set pin high on creation
pin = Pin(("gpiob", 21), Pin.IN, Pin.PULL_UP) # enable internal pull-up resistor
switch = Pin(("gpioc", 6), Pin.IN) # create input pin for a switch
switch.irq(lambda t: print("SW2 changed")) # enable an interrupt when switch state is changed
Hardware I2C bus
----------------
Hardware I2C is accessed via the :ref:`machine.I2C <machine.I2C>` class::
from machine import I2C
i2c = I2C("i2c0") # construct an i2c bus
print(i2c) # print device name
i2c.scan() # scan the device for available I2C slaves
i2c.readfrom(0x1D, 4) # read 4 bytes from slave 0x1D
i2c.readfrom_mem(0x1D, 0x0D, 1) # read 1 byte from slave 0x1D at slave memory 0x0D
i2c.writeto(0x1D, b'abcd') # write to slave with address 0x1D
i2c.writeto_mem(0x1D, 0x0D, b'ab') # write to slave 0x1D at slave memory 0x0D
buf = bytearray(8) # create buffer of size 8
i2c.writeto(0x1D, b'abcd') # write buf to slave 0x1D
Hardware SPI bus
----------------
Hardware SPI is accessed via the :ref:`machine.SPI <machine.SPI>` class::
from machine import SPI
spi = SPI("spi0") # construct a spi bus with default configuration
spi.init(baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB) # set configuration
# equivalently, construct spi bus and set configuration at the same time
spi = SPI("spi0", baudrate=100000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB)
print(spi) # print device name and bus configuration
spi.read(4) # read 4 bytes on MISO
spi.read(4, write=0xF) # read 4 bytes while writing 0xF on MOSI
buf = bytearray(8) # create a buffer of size 8
spi.readinto(buf) # read into the buffer (reads number of bytes equal to the buffer size)
spi.readinto(buf, 0xF) # read into the buffer while writing 0xF on MOSI
spi.write(b'abcd') # write 4 bytes on MOSI
buf = bytearray(4) # create buffer of size 8
spi.write_readinto(b'abcd', buf) # write to MOSI and read from MISO into the buffer
spi.write_readinto(buf, buf) # write buf to MOSI and read back into the buf
Disk Access
-----------
Use the :ref:`zephyr.DiskAccess <zephyr.DiskAccess>` class to support filesystem::
import vfs
from zephyr import DiskAccess
block_dev = DiskAccess('SDHC') # create a block device object for an SD card
vfs.VfsFat.mkfs(block_dev) # create FAT filesystem object using the disk storage block
vfs.mount(block_dev, '/sd') # mount the filesystem at the SD card subdirectory
# with the filesystem mounted, files can be manipulated as normal
with open('/sd/hello.txt','w') as f: # open a new file in the directory
f.write('Hello world') # write to the file
print(open('/sd/hello.txt').read()) # print contents of the file
Flash Area
----------
Use the :ref:`zephyr.FlashArea <zephyr.FlashArea>` class to support filesystem::
import vfs
from zephyr import FlashArea
block_dev = FlashArea(4, 4096) # creates a block device object in the frdm-k64f flash scratch partition
vfs.VfsLfs2.mkfs(block_dev) # create filesystem in lfs2 format using the flash block device
vfs.mount(block_dev, '/flash') # mount the filesystem at the flash subdirectory
# with the filesystem mounted, files can be manipulated as normal
with open('/flash/hello.txt','w') as f: # open a new file in the directory
f.write('Hello world') # write to the file
print(open('/flash/hello.txt').read()) # print contents of the file
Sensor
------
Use the :ref:`zsensor.Sensor <zsensor.Sensor>` class to access sensor data::
import zsensor
from zsensor import Sensor
accel = Sensor("fxos8700") # create sensor object for the accelerometer
accel.measure() # obtain a measurement reading from the accelerometer
# each of these prints the value taken by measure()
accel.get_float(zsensor.ACCEL_X) # print measurement value for accelerometer X-axis sensor channel as float
accel.get_millis(zsensor.ACCEL_Y) # print measurement value for accelerometer Y-axis sensor channel in millionths
accel.get_micro(zsensor.ACCEL_Z) # print measurement value for accelerometer Z-axis sensor channel in thousandths
accel.get_int(zsensor.ACCEL_X) # print measurement integer value only for accelerometer X-axis sensor channel
|
