EV6240 Datasheet, PDF(44/47 Page) CML Microcircuits – Opto-Isolated serial interface capability

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EV6240 Datasheet, PDF (44/47 Pages) CML Microcircuits – Opto-Isolated serial interface capability

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Evaluation Kit for CMX624/CMX644A

EV6240

State 17

Set up the CMX644A to Tx High Band Scrambled PSK 1âs (marks) with Guard Tone if selected.

Start a 770ms Timer.

State 18

Wait until 770ms Timer expires then turn on Modem CD LED and goto Data Transfer Mode.

Note:

Handshaking sequences are only performed when the EV6240 evaluation board is operated in the

default Evaluation Mode (Modem Mode, AT@E0).

To ensure successful handshaking and data transfer between the EV6240 and third party modems,

users should ensure their third party modem is configured to the correct protocol (see third party AT

command documentation).

The EV6240 ITU-T handshaking firmware incorporates the V25 calling and answering procedures.

The EV6240 ITU-T handshaking firmware will only allow the Calling Modem to connect with a modem

that is using the V25 answering sequence.

After dialling, the ITU-T calling modem will pulse the 1300Hz calling tone (0.6s on and 1.5s off) until

the 2100Hz answer tone has been detected. This V25 calling procedure is not shown on Figures 8

and 10.

Handshaking sequences may be aborted by pushing any key prior to entering data transfer mode.

Whilst in data transfer mode the user can return to AT Command mode by typing the escape code

sequence (+++). The escape code guard time must have expired to successfully return to the AT

Command mode.

The CD(Carrier Detect) LEDâs are only used during the Modem Mode handshaking sequences and

data transfer.

1.6.6.7 Use of CMX644A with early EV6240 Kits

Early (Rev A) EV6240 kits were designed for evaluating the CMX644: They can be easily modified to

evaluate the CMX644A.

(a) Connect capacitor C44 (1.0ÂµF ceramic) between U6 pin 23 and Ground (0v).

(b) Connect capacitor C45 (1.0ÂµF ceramic) between U8 pin 23 and Ground (0v).

Rev B (and later) versions of the EV6240 kit do not require hardware modification for use with the

CMX644A, although a later version of firmware, (available on the CML web site) may need to be

programmed into the PIC ÂµC. The CMX644 can still be evaluated on modified EV6240 kits, providing

an earlier version of firmware is used. Please contact CML for details.

UM6240/3

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