SiLabs Si2400 - Connect One

Reference Design
SL-IERB Internet-Enabling Reference Board
for Silicon Laboratories’ Si2400URT-EVB
General:
Connect One’s SL-IERB adapter is a daughterboard designed for use with Silicon
Laboratories’ Si2400URT-EVB evaluation board, for the purpose of evaluating
Connect One’s iChip Internet Controller with Silicon Laboratories’ Si2400
ISOmodem. The adapter is populated with Connect One’s CO561AD-S iChip Internet
Controller. When inserted into headers provided on the Si2400URT-EVB, the SL-
IERB Internet-enables SiLabs’ evaluation board. It allows a processor to issue
Connect One AT+i TM commands to invoke Internet protocols, in addition to issuing
the normal Si2400 AT commands for direct modem operations. Connect One’s AT+i
Programmer’s Manual specifies the required iChip configuration for operation with an
Si2400 modem via the MTYP parameter (see Appendix A).
Block diagram:
DB-9
female
RS232
to Host
Processor
Si2400URT- EVB Rev. 3.0
JP3 JP7
RJ-11
Telephone
socket
J2
J2A
SL-IERB Rev. 1.00
iChip
CO561AD-S
Connect One Ltd. 2 Hanagar Street Kfar Saba, 44425 Israel Tel: +972-9-766-0456 Fax: +972-9-766-0461
Email: info@connectone.com URL: http://www.connectone.com

Reference Design
Interface:
The SL-IERB daughterboard plugs on to the Si2400URT-EBV on the JP3 and JP7
sockets. See Table 1 and Table 2 for pin assignments. Table 3 includes SL-IERB pin
descriptions.
PIN NUMBER
Pin description
ON JP3
Si2400URT-EVB
Pin description
ON J2
SL-IERB Adapter
1 ANA OUT NOT USED
2 GND GND
3 AUDIO IN NOT USED
4 GND GND
5 GPIO1 NOT USED
6 GPIO2 NOT USED
7 GPIO3 -DTRM
8 GPIO4 -CDM
9 RESET RESET
10 RXD_T TXDM
11 CTS_T2 -CTSM
12 TXD_T RXDM
13 TXD_R RXDH232
14 CLK_OUT NOT USED
15 RXD_R TXDH232
16 CLK_IN NOT USED
Table 1
PIN NUMBER
Pin description
ON JP7
Si2400URT-EVB
Pin description
ON J2A
SL-IERB Adapter
1 CTS_T NOT USED
2 VD VCC (3.3Vdc )
Table 2
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Reference Design
Pin Descriptions:
Pin Name
-DTRM
-CDM
RESET
TXDM
-CTSM
RXDM
RXDH232
TXDH232
Pin Description
Data Terminal Ready Modem (Output, TTL Active Low):
This pin is used to drop the modem carrier.
Carrier Detect Modem (Input, TTL Active Low):
This pin gets the carrier detect signal from the modem.
Modem and iChip Reset:
An active low RESET input resets both the iChip and the modem.
Transmit Data Modem (Output TTL):
This pin supplies asynchronous serial transmit data from the iChip
to the modem.
Clear To Send Modem (Input, TTL Active Low):
This pin provides the clear to send signal for the asynchronous
serial port when the flow control option is enabled. When -CTSM
is asserted, the transmitter begins transmission of a data frame, if
any is available. If –CTSM is de-asserted, the transmitter holds the
data in the serial port transmit register. The value of –CTMS
is checked only at the beginning of the transmission of a frame.
Receive Data Modem (Input, TTL):
This pin supplies asynchronous serial receive data from the modem
to the iChip.
Receive Data Host (Input, RS232):
This pin supplies asynchronous serial receive data from the Host
processor to iChip.
Transmit Data Host (Output, RS232):
This pin supplies asynchronous serial transmit data from the iChip
to the Host processor.
Table 3
DB9 - J1
SL-IERB
iChip
JP3 ON Si2400
Si2400URT-
EVB Rev. 3
RJ11
JP7
HOLE
Figure 1. Mechanical Diagram.
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Reference Design
SL-IERB Daughterboard Layout:
Rev. 1.00
SiLAB1
To Si2400 EVB JP3 / JP7
iChip
CO561AD-S
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Reference Design
Changes Required on Si2400URT-EVB REV 3.0 Board:
The Si2400 board must undergo several changes in order to support Connect One’s
SL-IERB adapter. See Figure 2. Following is a list of the required changes:
• Remove R56 AND R54
• Add 0O resistors on R55 and R57
• Make sure R53 is unpopulated
• Make sure R52, R58 and R59 are populated with 0O resistors
• Install jumpers JP5 and JP6
• Remove jumper JP2 pin 8
• Remove jumper JP2 pin 11
• Assemble a low profile oscillator on X1
Note : The SL-IERB adapter works only with the Si2400URT-EVB REV 3.0 board.
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Reference Design
Use Low
Profile
Oscillator
R53 not
populated
R52, R58
and R59
populated
Remove JP2 pin
8 and pin11
Install Jumpers
JP5 & JP6
Remove R56 and R54
Add 0O resistors R55 and R57
Figure 2. Changes needed on Si2400 REV 3.0 board to populate SL-IERB
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Reference Design
Bill of Materials for SL-IERB Adapter:
# Qty Reference Designator Description Manufacturer
1 2 C1, C2 22PF
2 2 C3, C15 10UF/6.3V TAN SIZE A
3 6 C6, C9, C11, C12, C13, C14 0.1UF
4 1 C5 1NF
5 1 J2 HEADER 8X2 FEMALE
6 1 J2A HEADER 1X2 FEMALE
7 1 R1 4.7K
8 1 R2 47K
9 1 SW1 PUSHBUTTON
10 1 U1 CO561AD-S/20PC-3 Connect One
11 1 U18 MAX3238CAI MAXIM
12 1 Y1 18.432MHz
Table 4
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Reference Design
Figure 3. SL-IERB Application Circuit Schematic
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Reference Design
Appendix A
Configuring iChip to Operate with
Silicon Labs’ Si2400 ISOmodem
+iMTYP - Set type of modem connected to iChip
Syntax: AT+iMTYP=n Set the modem type
Parameters: n = 0 .. 2
Command Options:
n = 0
n = 1
n = 2
Standard, Hayes compatible, dial-up modem
Silicon Laboratories Si2400. See note below.
GSM modem
Default: n = 0 Standard, Hayes compatible
Scope:
Result code:
iChip.
I/OK If n is within limits.
I/ERROR Otherwise.
AT+iMTYP?
Returns current modem type designator.
The reply is followed by I/OK.
AT+iMTYP=? Returns the message "0-2".
The reply is followed by I/OK.
Note: Configure the iChip to work with the Silicon Laboratories Si2400 as follows:
1. AT+iMTYP=1
2. AT+iMIS='AT'
3. AT+iBDRF=3
4. AT+iBDRM=3
…Excerpt from the AT+i Programmer’s Manual
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July 2001