CodeIgniter's from() method ignores table passed in as a second parameter in an attempted JOIN query

I want to display data from both the users table and users_profiles table in one HTML table. I want to link table records so that usrID = usrID. There is a one-to-one relationship between the rows in these tables.

Originally, I was only fetching users_profiles records from my controller and it worked great.

Controller:

$data['query'] = $this->db->query('SELECT * FROM users_profiles');
$this->load->view('users/users_view',$data);

View:

<?php foreach($query->result_array() as $row): ?>
    <tr class="even gradeC">
        <td><?php echo $row['usrID']</td>
        <td><?php echo $row['usrName'];?></td>
    </tr>
<? endforeach; ?>

Here is my new, flawed coding attempt using query builder:

$this->db->select('users.usrID, users_profiles.usrpID');
$this->db->from('users', 'users_profiles');
$this->db->join('users', 'users.usrID = users_profiles.usrpID');
$result = $this->db->get();

Unfortunately, my query builder script is emitting an error.

A Database Error Occurred Error Number: 1054 Unknown column 'users_profiles.usrpID' in 'on clause'

How should this be fixed?