Neo 1973 and Neo FreeRunner gsm modem

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This page is about the Neo1973 GTA01 (and GTA02) GSM Modem, based on the Ti Calypso chipset.
 
This page is about the Neo1973 GTA01 (and GTA02) GSM Modem, based on the Ti Calypso chipset.
 +
 +
== AT command interface ==
 +
 +
=== Standard AT commands ===
 +
The GSM modem follows GSM TS07.05, 07.07 and 07.10 very closely.
 +
 +
FIXME: Describe how those documents can be obtained.
 +
 +
=== Ti proprietary AT commands ===
 +
 +
there are a few of them, but none of them are really required for regular operation of the device.  Due to NDA issues, OpenMoko cannot provide a reference documentation to those commands.  Using the standards-compliant '''AT+CLAC''', you will notice that the non-standard commands also show up in the command listing.
 +
 +
You will also notice that those non-standard commands are prefixed with '''AT%''' rather than '''AT+''' for the standards-compliant commands.
 +
 +
Thus, we welcome our user and developer community to play with those commands and document them here.  Since we never have released any NDA documentation to our community, there is no legal issue.
  
 
== GSM Modem OpenMoko commands ==
 
== GSM Modem OpenMoko commands ==
  
−
The Ti calypso GSM Modem firmware has been extended by OpenMoko specific AT         commands.  This page doucments those commands.
+
The Ti calypso GSM Modem firmware has been extended by OpenMoko specific AT
 +
commands.  This page doucments those commands.
  
 
FIXME!
 
FIXME!
Line 11: Line 27:
 
=== Problem description ===
 
=== Problem description ===
  
−
For power management reasons, it is absolutely neccessary that only the minimal     required parts of the device are powered at any given time.  If you carry your
+
For power management reasons, it is absolutely neccessary that only the minimal  
 +
required parts of the device are powered at any given time.  If you carry your
 
Neo in your pocket, then all it should do is stay online with the GSM network,  
 
Neo in your pocket, then all it should do is stay online with the GSM network,  
 
and notify you in case there's an incoming call/sms (like other phones).
 
and notify you in case there's an incoming call/sms (like other phones).

Revision as of 16:19, 26 July 2007

This page is about the Neo1973 GTA01 (and GTA02) GSM Modem, based on the Ti Calypso chipset.

Contents

AT command interface

Standard AT commands

The GSM modem follows GSM TS07.05, 07.07 and 07.10 very closely.

FIXME: Describe how those documents can be obtained.

Ti proprietary AT commands

there are a few of them, but none of them are really required for regular operation of the device. Due to NDA issues, OpenMoko cannot provide a reference documentation to those commands. Using the standards-compliant AT+CLAC, you will notice that the non-standard commands also show up in the command listing.

You will also notice that those non-standard commands are prefixed with AT% rather than AT+ for the standards-compliant commands.

Thus, we welcome our user and developer community to play with those commands and document them here. Since we never have released any NDA documentation to our community, there is no legal issue.

GSM Modem OpenMoko commands

The Ti calypso GSM Modem firmware has been extended by OpenMoko specific AT commands. This page doucments those commands.

FIXME!

Wakeup of CPU from GSM Modem

Problem description

For power management reasons, it is absolutely neccessary that only the minimal required parts of the device are powered at any given time. If you carry your Neo in your pocket, then all it should do is stay online with the GSM network, and notify you in case there's an incoming call/sms (like other phones).

During that time, the Neo1973 Application Processor (s3c24xx) is suspended, i.e. not powered at all. The SDRAM is in self-refresh mode.

In this suspend mode (which Samsung calls by the funny name of POWER_OFF), the processor is not able to receive any data from the GSM Modem. Nor is it able to detect incoming characters and wake up the CPU. The only wake up sources are a certain set of external interrupts (EINT).

Thus, the GSM Modem GPIO line IO1 was connected with the Samsung EINT1, and the GSM Modem firmware contains some special logic to generate an interrupt (and thus wake-up event) to the CPU.

Logic for problem solution

Preconditions

  1. The default state of GSM Modem output IO1 is logical LOW.

Anytime the modem has pending data on the MODEM-UART channel, it

  1. checks if CTS_MODEM permits sending of data
    1. if CTS_MODEM permits sending of UART data, go to '4.2'
  2. [implicit: CTS_MODEM does not permit sending of UART data]
    1. set IO1 line to logical HIGH level
    2. buffer modem data [until buffer is full, after which data gets discarded]
  3. wait until CTS_MODEM permits sending of UART data
  4. as soon as CTS_MODEM permits sending of UART data,
    1. set IO1 back to logical LOW level
    2. start sending of UART data
  5. once all data is transmitted, return to idle state. When next data item is to be transmitted, start again from '1'

Software implementation

Retrieved from "http://wiki.openmoko.org/index.php?title=Neo_1973_and_Neo_FreeRunner_gsm_modem&oldid=14170"
Personal tools

This page is about the Neo1973 GTA01 (and GTA02) GSM Modem, based on the Ti Calypso chipset.

AT command interface

Standard AT commands

The GSM modem follows GSM TS07.05, 07.07 and 07.10 very closely.

FIXME: Describe how those documents can be obtained.

Ti proprietary AT commands

there are a few of them, but none of them are really required for regular operation of the device. Due to NDA issues, OpenMoko cannot provide a reference documentation to those commands. Using the standards-compliant AT+CLAC, you will notice that the non-standard commands also show up in the command listing.

You will also notice that those non-standard commands are prefixed with AT% rather than AT+ for the standards-compliant commands.

Thus, we welcome our user and developer community to play with those commands and document them here. Since we never have released any NDA documentation to our community, there is no legal issue.

GSM Modem OpenMoko commands

The Ti calypso GSM Modem firmware has been extended by OpenMoko specific AT commands. This page doucments those commands.

FIXME!

Wakeup of CPU from GSM Modem

Problem description

For power management reasons, it is absolutely neccessary that only the minimal required parts of the device are powered at any given time. If you carry your Neo in your pocket, then all it should do is stay online with the GSM network, and notify you in case there's an incoming call/sms (like other phones).

During that time, the Neo1973 Application Processor (s3c24xx) is suspended, i.e. not powered at all. The SDRAM is in self-refresh mode.

In this suspend mode (which Samsung calls by the funny name of POWER_OFF), the processor is not able to receive any data from the GSM Modem. Nor is it able to detect incoming characters and wake up the CPU. The only wake up sources are a certain set of external interrupts (EINT).

Thus, the GSM Modem GPIO line IO1 was connected with the Samsung EINT1, and the GSM Modem firmware contains some special logic to generate an interrupt (and thus wake-up event) to the CPU.

Logic for problem solution

Preconditions

  1. The default state of GSM Modem output IO1 is logical LOW.

Anytime the modem has pending data on the MODEM-UART channel, it

  1. checks if CTS_MODEM permits sending of data
    1. if CTS_MODEM permits sending of UART data, go to '4.2'
  2. [implicit: CTS_MODEM does not permit sending of UART data]
    1. set IO1 line to logical HIGH level
    2. buffer modem data [until buffer is full, after which data gets discarded]
  3. wait until CTS_MODEM permits sending of UART data
  4. as soon as CTS_MODEM permits sending of UART data,
    1. set IO1 back to logical LOW level
    2. start sending of UART data
  5. once all data is transmitted, return to idle state. When next data item is to be transmitted, start again from '1'

Software implementation