2-way data binding in attribute directive - Angular

How to use two way data binding for attribute level directive in Angular? I cannot use ngModel because I am using this inside a div with contentEditable = true. I want to send injected input to this div into my syntax-highlight directive and if there is any change to the text inside the syntax-highlight directive it should be reflected in the UI. How can i do this?

 <div id="myTextEditor" maxlength="700" contenteditable="true" syntax-highlight="handleKeyPress">
 </div>