.. _Flash_Code_Output:

Flash Code Output
=================

Most OpenECU modules can flash an LED to inform the user of the state of the
ECU. This is particularly useful when other means of communication with the
ECU, such as CAN, are not available.

- Supported ECUs: M220, M250, M460, M461, M670.

Setup
-----

Connect an LED between V\ :sub:`pwr`\  (ECU power supply pin) and the flash
code pin.

.. note:: The flash code pin cannot supply enough current for a lamp. An LED
   must be used.

- Use an `LED calculator <https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-led-series-resistor>`_ 
  for selecting the proper series resistor if it is not built into your LED.

- Refer to the **Technical Specification** to find the flash code pin.

Procedure
---------

Once the LED is connected and power is supplied to the ECU, the LED will begin
flashing. The flash sequence represents a three-digit code, where each digit
is flashed a number of times equal to its value.

The following diagram illustrates the flash sequence for code 113:

.. image:: flash_code_output_img1.jpg

Each of the marks lasts for a specific duration:

.. list-table:: Flash Sequence Durations
   :widths: 50 50
   :header-rows: 1

   * - Mark
     - Duration and Meaning
   * - Start of log mark
     - 3 sec - marks the start of the flash code
   * - Digit mark
     - 1 sec - marks the start of a digit
   * - d\ :sub:`n`\ (x)
     - OFF for 0.5 sec, ON for 0.5 sec, repeated x times
   * - End code mark
     - 3 sec - marks the end of the flash code

.. image:: flash_code_output_img2.gif

Mark durations are as follows:

======================  ==========================
Mark                    Duration and Meaning
======================  ==========================
Start of log mark       3 sec - marks start of code
Digit mark              1 sec - start of a digit
d\ :sub:`n`\ (x)        OFF for 0.5 sec, ON for 0.5 sec, repeated x times
End code mark           3 sec - end of code
======================  ==========================

- Multiple codes may be present.
- If your ECU does not flash a code, consult :ref:`Dead ECU <dead_ecu>`.

Flash Code Meanings
-------------------

======================  ===================================================================================
Code                    Meaning
======================  ===================================================================================
111                     Running normally in application mode
112                     In reprogramming mode due to :ref:`negative FEPS <ecu_recovery>`
113                     In reprogramming mode due to :ref:`positive FEPS <ecu_recovery>`
114                     In reprogramming mode due to FEPSless request (CCP)
115                     In reprogramming mode due to no valid application
116                     In reprogramming mode due to FEPS pin electrical failure
117                     In reprogramming mode due to :ref:`repeated reset in application mode <ecu_reset>`
118                     In reprogramming mode due to :failed application checksum
119                     In reprogramming mode due to FEPSless ISO reprogramming request
121                     In reprogramming mode due to an unknown failure
123                     In reprogramming mode due to :ref:`a watchdog reset <ecu_reset>`
128                     In reprogramming mode due to a failed RAM check
222                     In reprogramming mode due to  no valid license
======================  ===================================================================================