Pycom GPy and ssd1306.py. writevto()
Pycom GPy and ssd1306.py. writevto()
I trying to port working code from Pyboard (or ESP8266, both works) to a GPy.
The GPy runs (Pycom MicroPython 1.20.2.r1 [v1.11-a5aa0b8] on 2020-09-09; GPy with ESP32
The code depends on the font_to_py.py library, which specifies that the 'official' ssd1306.py driver be used.
This driver contains the following:
def write_data(self, buf):
self.write_list[1] = buf
self.i2c.writevto(self.addr, buf)
Initializing ssd1306.py returns:
: AttributeError: 'I2C' object has no attributes 'writevto'
I checked:
>>> dir(I2C)
['__class__', '__name__', 'MASTER', 'deinit', 'init', 'readfrom', 'readfrom_into', 'readfrom_mem', 'readfrom_mem_into', 'scan', 'writeto', 'writeto_mem']
>>>
What hackery should I perform to get this to work?
The GPy runs (Pycom MicroPython 1.20.2.r1 [v1.11-a5aa0b8] on 2020-09-09; GPy with ESP32
The code depends on the font_to_py.py library, which specifies that the 'official' ssd1306.py driver be used.
This driver contains the following:
def write_data(self, buf):
self.write_list[1] = buf
self.i2c.writevto(self.addr, buf)
Initializing ssd1306.py returns:
: AttributeError: 'I2C' object has no attributes 'writevto'
I checked:
>>> dir(I2C)
['__class__', '__name__', 'MASTER', 'deinit', 'init', 'readfrom', 'readfrom_into', 'readfrom_mem', 'readfrom_mem_into', 'scan', 'writeto', 'writeto_mem']
>>>
What hackery should I perform to get this to work?
Re: Pycom GPy and ssd1306.py. writevto()
writevto was an optimisation added a little while ago to MicroPython that helps with these sorts of drivers that need to send commands over I2C in the form of <prefix><chunk of data> and it prevents having to create a new buffer every time with the concatenated data.
You can see the commit that was applied to ssd1306.py to take advantage of this feature here: https://github.com/micropython/micropyt ... 87332d6d59 -- just do the reverse change and you should hopefully work on Pycom.
Re: Pycom GPy and ssd1306.py. writevto()
There is a ssd1306 driver in the pycom source tree. https://github.com/pycom/pycom-micropyt ... rs/display
Re: Pycom GPy and ssd1306.py. writevto()
I tried it and get: AttributeError: 'I2C' object has no attribute 'start'Roberthh wrote: ↑Thu Oct 29, 2020 6:36 amThere is a ssd1306 driver in the pycom source tree. https://github.com/pycom/pycom-micropyt ... rs/display
A missing method? What was it supposed to do?
Re: Pycom GPy and ssd1306.py. writevto()
That's the old soft I2C method. I have a modified version which I used with Pycom Micropython: https://github.com/robert-hh/pycom-micr ... ssd1306.py
AFAI recall I made a PR for that, but it did not make it's way into the main repository.
AFAI recall I made a PR for that, but it did not make it's way into the main repository.
Re: Pycom GPy and ssd1306.py. writevto()
I'm out of my depth inside git. But what I tried was to open the link supplied. I came upon the document with marked up changes, but I don't know how to roll it back properly. What I did instead is to use the parent code. Is that correct?jimmo wrote: ↑Thu Oct 29, 2020 4:30 amwritevto was an optimisation added a little while ago to MicroPython that helps with these sorts of drivers that need to send commands over I2C in the form of <prefix><chunk of data> and it prevents having to create a new buffer every time with the concatenated data.
You can see the commit that was applied to ssd1306.py to take advantage of this feature here: https://github.com/micropython/micropyt ... 87332d6d59 -- just do the reverse change and you should hopefully work on Pycom.
In any case, I ran into the same problem as with the Pycom driver mentioned by Roberthh:
Extract from ssd1306.py
def write_data(self, buf):
self.temp[0] = self.addr << 1
self.temp[1] = 0x40 # Co=0, D/C#=1
self.i2c.start()
self.i2c.write(self.temp)
self.i2c.write(buf)
self.i2c.stop()
Running the program I get:
Traceback (most recent call last):
File "<stdin>", line 2, in <module>
File "/flash/lib/ssd1306_setup.py", line 43, in <module>
File "/flash/lib/ssd1306_setup.py", line 41, in setup
File "/flash/lib/ssd1306.py", line 99, in __init__
File "/flash/lib/ssd1306.py", line 36, in __init__
File "/flash/lib/ssd1306.py", line 63, in init_display
File "/flash/lib/ssd1306.py", line 91, in show
File "/flash/lib/ssd1306.py", line 109, in write_data
AttributeError: 'I2C' object has no attribute 'start'
So, unless I figure out what I2C.start() is supposed to do, I'm stumped.
Any suggestions?
Re: Pycom GPy and ssd1306.py. writevto()
start() and stop() are methods of the softI2C class, which is not implemented by Pycom. For ease of use, instead of the link I copy my code below. Note that is is more a question about the Pycom brand of Micropython and therefore better to be discussed in their forum.
Code: Select all
# MicroPython SSD1306 OLED driver, I2C and SPI interfaces
from micropython import const
import framebuf
# register definitions
SET_CONTRAST = const(0x81)
SET_ENTIRE_ON = const(0xa4)
SET_NORM_INV = const(0xa6)
SET_DISP = const(0xae)
SET_MEM_ADDR = const(0x20)
SET_COL_ADDR = const(0x21)
SET_PAGE_ADDR = const(0x22)
SET_DISP_START_LINE = const(0x40)
SET_SEG_REMAP = const(0xa0)
SET_MUX_RATIO = const(0xa8)
SET_COM_OUT_DIR = const(0xc0)
SET_DISP_OFFSET = const(0xd3)
SET_COM_PIN_CFG = const(0xda)
SET_DISP_CLK_DIV = const(0xd5)
SET_PRECHARGE = const(0xd9)
SET_VCOM_DESEL = const(0xdb)
SET_CHARGE_PUMP = const(0x8d)
# Subclassing FrameBuffer provides support for graphics primitives
# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html
class SSD1306(framebuf.FrameBuffer):
def __init__(self, width, height, external_vcc):
self.width = width
self.height = height
self.external_vcc = external_vcc
self.pages = self.height // 8
self.buffer = bytearray(self.pages * self.width)
super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
self.init_display()
def init_display(self):
for cmd in (
SET_DISP | 0x00, # off
# address setting
SET_MEM_ADDR, 0x00, # horizontal
# resolution and layout
SET_DISP_START_LINE | 0x00,
SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0
SET_MUX_RATIO, self.height - 1,
SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0
SET_DISP_OFFSET, 0x00,
SET_COM_PIN_CFG, 0x02 if self.width > 2 * self.height else 0x12,
# timing and driving scheme
SET_DISP_CLK_DIV, 0x80,
SET_PRECHARGE, 0x22 if self.external_vcc else 0xf1,
SET_VCOM_DESEL, 0x30, # 0.83*Vcc
# display
SET_CONTRAST, 0xff, # maximum
SET_ENTIRE_ON, # output follows RAM contents
SET_NORM_INV, # not inverted
# charge pump
SET_CHARGE_PUMP, 0x10 if self.external_vcc else 0x14,
SET_DISP | 0x01): # on
self.write_cmd(cmd)
self.fill(0)
self.show()
def poweroff(self):
self.write_cmd(SET_DISP | 0x00)
def poweron(self):
self.write_cmd(SET_DISP | 0x01)
def contrast(self, contrast):
self.write_cmd(SET_CONTRAST)
self.write_cmd(contrast)
def invert(self, invert):
self.write_cmd(SET_NORM_INV | (invert & 1))
def show(self):
x0 = 0
x1 = self.width - 1
if self.width == 64:
# displays with width of 64 pixels are shifted by 32
x0 += 32
x1 += 32
self.write_cmd(SET_COL_ADDR)
self.write_cmd(x0)
self.write_cmd(x1)
self.write_cmd(SET_PAGE_ADDR)
self.write_cmd(0)
self.write_cmd(self.pages - 1)
self.write_data(self.buffer)
class SSD1306_I2C(SSD1306):
def __init__(self, width, height, i2c, addr=0x3c, external_vcc=False):
self.i2c = i2c
self.addr = addr
self.temp = bytearray(2)
super().__init__(width, height, external_vcc)
def write_cmd(self, cmd):
self.temp[0] = 0x80 # Co=1, D/C#=0
self.temp[1] = cmd
self.i2c.writeto(self.addr, self.temp)
def write_data(self, buf):
self.i2c.writeto(self.addr, b'\x40' + buf)
class SSD1306_SPI(SSD1306):
def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
self.rate = 10 * 1024 * 1024
dc.init(dc.OUT, value=0)
res.init(res.OUT, value=0)
cs.init(cs.OUT, value=1)
self.spi = spi
self.dc = dc
self.res = res
self.cs = cs
import time
self.res(1)
time.sleep_ms(1)
self.res(0)
time.sleep_ms(10)
self.res(1)
super().__init__(width, height, external_vcc)
def write_cmd(self, cmd):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(0)
self.cs(0)
self.spi.write(bytearray([cmd]))
self.cs(1)
def write_data(self, buf):
self.spi.init(baudrate=self.rate, polarity=0, phase=0)
self.cs(1)
self.dc(1)
self.cs(0)
self.spi.write(buf)
self.cs(1)
Re: Pycom GPy and ssd1306.py. writevto()
Thank you. I've got it working with this library. It's unbelievable how many variants of ssd1306.py is floating around.Roberthh wrote: ↑Thu Oct 29, 2020 8:21 amThat's the old soft I2C method. I have a modified version which I used with Pycom Micropython: https://github.com/robert-hh/pycom-micr ... ssd1306.py
AFAI recall I made a PR for that, but it did not make it's way into the main repository.
Re: Pycom GPy and ssd1306.py. writevto()
Roberthh wrote: ↑Thu Oct 29, 2020 9:25 amstart() and stop() are methods of the softI2C class, which is not implemented by Pycom. For ease of use, instead of the link I copy my code below. Note that is is more a question about the Pycom brand of Micropython and therefore better to be discussed in their forum.
This forum is clued up on ssd1306.py. And active, I posted last night, and this morning my problem was solved in 30 minutes.