Evaluation Kit for CMX602B

EV6021

 2000 Consumer Microcircuits Limited

19

UM6021/4

1.6.3

Firmware

This section describes the operation of the EV6021 kit using the LCD module and the demonstration

selection switches SW2 to SW4. It also describes the sequence of events followed by the available

demonstrations.

1.6.3.1

Start-up

As described in Quick start section.

The opening messages will be EF6021 Vx.x (where x.x represents the version number), followed by

an indication of the current selection from switches SW2 to SW4.

1.6.3.2

Demonstration Selection

Use switches to alter the selection as indicated on the printed circuit silkscreen:

SW2 - Adjunct Box or Feature Phone.

SW3 - BT or Bellcore.

SW4 - Type1 or Type2.

When a new selection has been made the start up messages will be displayed on the LCD until a new CLI

message has been received.

1.6.3.3

BT type 1 demonstration

This demonstration covers the BT on-hook service initiated by a line reversal followed by an alert

tone, see flowchart in CMX602B datasheet (application notes section). CLI message parameters are

displayed on the LCD.

On the EV6021 board, FET TR9 is switched on to provide wetting current for 15ms during the silent

period between the alert tone and the FSK data. A resistor can be fitted in the R7 position if a

current wetting pulse is required.

FET TRI0 is switched on during the FSK receive period.

If an ac termination is required,

components can be fitted in positions R4, R6 and C3.

1.6.3.4

Bellcore type 1 demonstration

This demonstration covers the Bellcore on-hook service associated with ringing, see flowchart in

CMX602B datasheet (application notes section). Any ringing of duration < 500ms is assumed to be

a line reversal and is ignored. CLI message parameters are displayed on the LCD.

Relay 1 is energised during the FSK receive period. If an ac termination is required, components

can be fitted in positions R4, R6 and C3.

1.6.3.5

BT and Bellcore type 2 demonstration

This demonstration covers both the BT and Bellcore off-hook caller ID services, see flowchart in

CMX602B datasheet (application notes section).

If ‘Feature Phone’ is selected, the local speech path is enabled and muted when a CAS tone is

detected (when the CMX602B DET output is set in tone alert mode, termed early mute). Also signals

from the line, e.g. CAS tone, will be taken from the Rx side of the 2 to 4 wire interface.

If ‘Adjunct Box’ is selected, the link to an external telephone, socket J2, is muted when a valid CAS

tone has been received (when CMX602B IRQN pin goes low in tone alert mode, termed late mute).

If the EV6021 is linked to a PC, see section 1.6.2, the point at which muting occurs can be toggled

between early and late.