ESP8266 Community Forum

- Mon Jan 19, 2015 4:46 pm #7742 Would the ESP8266 even have enough memory for the 1306 oled frame buffer?

- Mon Jan 19, 2015 4:49 pm #7743

Would the ESP8266 even have enough memory for the 1306 oled frame buffer?

I have seen versions without frame buffer, also 128*64=8192Bit = 1024Byte, so yeah.
However, all code versions I have seen use a lookup table for the characters. I was thinking about letting the user create that table in lua on the stack, so that people who don't use the module would not lose any RAM.
With static lookup table I still have >22k free ram after boot.

- Mon Jan 19, 2015 5:04 pm #7745

Would the ESP8266 even have enough memory for the 1306 oled frame buffer?

I have seen versions without frame buffer, also 128*64=8192Bit = 1024Byte, so yeah.
However, all code versions I have seen use a lookup table for the characters. I was thinking about letting the user create that table in lua on the stack, so that people who don't use the module would not lose any RAM.
With static lookup table I still have >22k free ram after boot.

Yeah I have seen some connected to the ESP8266 as well but the ones I saw didn't give any kind of code examples so I figured it was possible. I would love to be able to hook my oled up to one of these.

- Mon Jan 19, 2015 5:27 pm #7747 I've been playing around with a 128x64 I2C oled, the cheapest I could find, SSD1306 based controller - I haven't gotten it working yet! It does make the display change, but I was expecting it to flash, and it doesn't.

I copied a bunch of stuff over from Adafruit's excellent arduino libraries (qudos to her, she's made a giant contribution).
I also saw a few other examples on the web and many did the init procedure in a different order.
I had to track down some commands and another init example from the datasheet.

If this helps anyone get started then great!!

Code: Select all-- TODO fix this code so that it works. Anyone???

id=0  -- need this to identify (software) IC2 bus?
gpio= {[0]=3,[2]=4,[4]=2,[5]=1,[12]=6,[13]=7,[14]=5} -- this maps GPIO numbers to internal IO references
sda=gpio[12] -- connect to pin GPIO14
scl=gpio[14] -- connect to pin GPIO12
addr=0x3C -- the I2C address of our device

-- initialize i2c
i2c.setup(id,sda,scl,i2c.SLOW)

-- user defined function: read from reg_addr content of dev_addr
function read_reg(dev_addr, reg_addr)
     i2c.start(id)
     i2c.address(id, dev_addr ,i2c.TRANSMITTER)
     i2c.write(id,reg_addr)
     i2c.stop(id)
     i2c.start(id)
     i2c.address(id, dev_addr,i2c.RECEIVER)
     c=i2c.read(id,1)
     i2c.stop(id)
     return c
end

function write_reg(dev_addr, reg_addr, reg_val)
     i2c.start(id)
     i2c.address(id, dev_addr, i2c.TRANSMITTER)
     i2c.write(id, reg_addr)
     i2c.write(id, reg_val)
     i2c.stop(id)
end

function oled_command(cmd)
     write_reg(addr,0,cmd)
end

function display()
oled_command(0x21) -- set column addresses
oled_command(0x00) -- reset column start address
oled_command(0x7F) -- reset column end address
oled_command(0x22) -- set page addresses
oled_command(0x00) -- reset page start address
oled_command(0x07) -- reset page end address
end

function init() -- Initialises the 128x64 oled
print("starting")
oled_command(0xAE) -- turn off oled panel
oled_command(0xA8) -- set multiplex ratio to 1 byte following
oled_command(0x3F) -- 1/64 duty (N+1 MUX: 1-64))
oled_command(0xD3) -- set display offset to 1 byte following
oled_command(0x00) -- no offset

oled_command(0x40) -- set start line address
oled_command(0xA0) -- set segment remap
oled_command(0xC0) -- set COM output scan direction
oled_command(0xDA) -- set com pins hardware configuration to 1 byte following
oled_command(0x12) -- set pins

oled_command(0x81) -- set contrast control register
oled_command(0x7f) -- reset contrast to default value

oled_command(0xA4) -- set display on
oled_command(0xA6) -- set normal display
oled_command(0xD5) -- set display clock divide ratio/oscillator frequency
oled_command(0x80) -- set divide ratio

oled_command(0x8D) -- set Charge Pump enable/disable
oled_command(0x14) -- set(0x10) disable

oled_command(0xAF) -- turn on oled panel
print("Init done")
end

init()
for a=1,20 do
display()
tmr.delay(100000)
tmr.wdclr()
oled_command(0xA7)
display()

tmr.delay(100000)
tmr.wdclr()
oled_command(0xA6)
display()
end

Last edited by gwizz on Mon Jan 19, 2015 5:32 pm, edited 2 times in total.