Modes Of Operation; Clocking Scheme; Connectivity; Microusb Interface - Nokia RM-721 Service Manual

Modes of operation

Mode
NO_SUPPLY (Dead) mode means that the main battery is not present or its voltage is too low (below
N2200 PEARL_J master reset threshold) and that the back-up battery voltage is too low.
BACK_UP The main battery is not present or its voltage is too low but back-up battery voltage is
adequate and the 32 kHz oscillator is running (RTC is on).
PWR_OFF In this mode (warm), the main battery is present and its voltage is over N2200 PEARL_J
master reset threshold. All regulators are disabled, PurX is on low state, the RTC is on
and the oscillator is on. PWR_OFF (cold) mode is almost the same as PWR_OFF (warm),
but the RTC and the oscillator are off.
RESET RESET mode is a synonym for start-up sequence. RESET mode uses 32 kHz clock to count
the REST mode delay (typically 16ms).
SLEEP SLEEP mode is entered only from PWR_ON mode with the aid of SW when the system's
activity is low.
FLASHING FLASHING mode is for SW downloading.

Clocking scheme

In BB5.0, two main clocks are provided to the system: 38.4MHz RF clock produced by the RF section and
32.768kHz sleep clock produced by EM ASIC N2200 with an external crystal.
32 k Sleep Clock is always powered on after startup. Sleep clock is used by RAP for low-power operation.
SMPS Clk is 3.2 MHz clock line from RAP to EM ASIC N2200. In deep sleep mode, when VCTCXO is off, this signal
is set to '0'-state.
RF CLK Ext is 38.4 RF CLK Ext from Vapaus ASIC. It is buffered in the RF part and distributed to BTHFMTXRDS.

Connectivity

MicroUSB interface

The micro USB (Universal Serial Bus) provides a wired connectivity between a PC and peripheral devices. It is
a differential serial bus. USB 2.0 is supported with full speed (12 Mbps).
Hot swap is supported, which means that USB devices may be plugged in/out at any time.
This phone is equipped with a μUSB connector (B type) which accepts CA-101 or an appropriate 3
cable to establish a USB connection.

SIM interface

The phone has a SIM (Subscriber Identification Module) interface including a SIM connector. The connector
is only accessible when the battery is removed.
Page 5 – 10
Figure 22 MicroUSB connector
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Description
RM-721; RM-722
System Module
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