i2cClock.spin

{I2C Clock object on pin SCL_pin}


CON
  _clkmode = xtal1 + pll16x                                               'Standard clock mode * crystal frequency = 80 MHz
  _xinfreq = 5_000_000

  Tlow = 108
  Thigh = 90
  SCL_pin = 17

VAR
  long stack[10]                'Cog stack space
  byte cog

OBJ

PUB Start                       'Cog start method
    Stop
    cog := cognew(@_entry, @stack) + 1

PUB Stop                        'Cog stop method
    if cog
        cogstop(cog~ - 1)

DAT

DAT
        org 0
_entry


        rdlong sfreq, #0
        mov delay, cnt
        add delay, sfreq
        waitcnt delay, sfreq                    'Start delay of 1s

        or dira, clk_pin                        'Set data and clock to output

i2c_clk or outa, clk_pin
        call#highdlay
        andn outa, clk_pin
        call #lowdlay
        jmp #i2c_clk


highdlay mov time, cnt                          'Get current system clock time
        add time, t_high
        waitcnt time, t_high
highdlay_ret   ret

lowdlay mov time, cnt                           'Get current system clock time
        add time, t_low
        waitcnt time, t_low
lowdlay_ret   ret




clk_pin       long  |<SCL_pin
delay         long  0
t_high        long  Thigh
t_low         long  Tlow
time          long  0
sfreq         long  0
fit