SI2403 データシートの表示（PDF） - Silicon Laboratories
部品番号
コンポーネント説明
メーカー
SI2403 Datasheet PDF : 68 Pages
| |||
Si2403
4.12. Overcurrent Detection
4.14. Firmware Upgrades
The ISOmodem® chipset includes an overcurrent
detection feature that measures the loop current at a
programmable time after the Si2403 goes off-hook. This
allows the Si2403 to detect if it is connected to an
improper telephone line. The overcurrent detection
feature may be enabled by setting the OCDM bit (U70,
bit 11). OHT (U77, bits 8:0) sets the delay after off-hook
until the loop current is measured.
4.13. Global Operation
The ISOmodem chipset contains an integrated silicon
direct-access arrangement (Silicon DAA) that provides
a programmable line interface to meet international
telephone line interface requirements. “AN70: Si2456/
Si2433/Si2414/Si2403 Modem Designer’s Guide” gives
the DAA register settings required to meet international
PTT standards.
Additionally, the user-access registers (via the AT:U and
AT:R commands) may be programmed for country-
specific settings, such as dial tone, ring, ringback, and
busy tone. See AN70 for complete details.
The ISOmodem chipset contains an on-chip program
ROM that includes the firmware required for the
features listed in this data sheet. In addition, the Si2403
contains on-chip program RAM to accommodate minor
changes to the ROM firmware. This allows Silicon Labs
to provide future firmware updates to optimize the
characteristics of new modem designs and those
already deployed in the field. See AN70 for further
information.
4.15. EEPROM Interface
The ISOmodem chipset supports an optional serial
peripheral interface (SPI) bus serial EEPROM. The
EEPROM must support SPI mode 3 with a 16-bit
(8 kbit – 64 kbit range) address. Upon powerup, if a
pulldown resistor ≤10 kΩ is placed between D6 (Si2403,
pin 4) and GND, the Si2403 attempts to detect an
EEPROM. An installed EEPROM may contain custom
default settings, firmware upgrades, and/or user-defined
AT command macros for use in custom AT commands
or country codes.
4.16. AT Commands
At powerup, the Si2403 is in the AT command mode. In
command mode, the modem monitors the input (serial
or parallel) checking constantly for a valid command.
(AT commands are described in Table 8.)
20
Rev. 1.2
Share Link: 