Nokia 6088 Guide

Nokia Customer Care
6088 (RM-218)
Mobile Terminal
Baseband Description and
Troubleshooting
Issue 1 10/2006 Company Confidential ©2006 Nokia Corporation

6088 (RM218)
Baseband Description and Troubleshooting
Contents Page
Introduction............................................................................................................... 4
Baseband and RF Architecture................................................................................ 5
Power Up and Reset................................................................................................ 6
Power Up.......................................................................................................8
Power Key..............................................................................................8
Charger...................................................................................................8
External supply source is detected.........................................................8
Power Off.......................................................................................................8
Power Consumption and Operation Modes...................................................8
Power-off Mode ......................................................................................9
Sleep Mode ............................................................................................9
Active Mode............................................................................................9
Charging Mode.......................................................................................9
Power Distribution .................................................................................................. 10
Clock Distribution.................................................................................................... 11
TCXO...........................................................................................................12
SLEEP crystal circuit for 32.768 kHz ...........................................................14
SBI CLK Interface........................................................................................15
Backend IC and Camera Module Clocks.....................................................16
Flash Programming Error Codes ........................................................................... 16
Charging Operation................................................................................................ 17
Battery .........................................................................................................17
Charging Circuitry........................................................................................17
Charger Detection........................................................................................18
Charge Control ............................................................................................19
Audio ...................................................................................................................... 19
Keypad ................................................................................................................... 20
Display.................................................................................................................... 21
Camera and Flash Light LED................................................................................. 22
Universal Serial Bus (USB).................................................................................... 22
Accessories............................................................................................................ 24
Charging......................................................................................................24
Headset Detection.......................................................................................24
Data Access.................................................................................................25
R-UIM CARD.......................................................................................................... 25
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Test Points.............................................................................................................. 26
Main Board Top Layer Test Points ...............................................................26
Main Board Bottom Layer Test Points Troubleshooting ...............................27
Mobile Terminal is Dead...............................................................................30
Flash Memory Faults ...................................................................................31
Power Does Not Stay ON or the Mobile Terminal is Jammed......................32
Charger Faults.............................................................................................33
Audio Faults.................................................................................................34
Display Faults..............................................................................................38
Keypad Faults..............................................................................................39
Keypad Faults..............................................................................................40
Camera Faults.............................................................................................41
Camera Faults.............................................................................................42
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Baseband Description and Troubleshooting
Introduction
The mobile terminal using a CDMA single mode engine (Cellular/ 800) with
Qualcomm baseband consists of the followingASICs:
 Power Management IC, PM6610 (PM)
 Mobile Station Modem processor, MSM6025 (MSM)
 RFT6122 and RFR6122 are RF transmitter and receiver IC.
 128Mb Flash memory and 64Mb pSRAM memory
 Backend IC SPCA552E for image processing
The baseband (MSM) is consisted of an ARM7 processor, a CDMA processor, a
DFM processor, QDSP & codec, PLL, analog interface for RF and controllers for
GPIOs, RUIM, USB & peripheral interfaces, all of which are necessary to complete
the entire CDMA baseband system. ARM7 processor communicates with external
memory, backend IC and LCD through local address & memory buses. A QDSP4000
with codec inside the Mobile Station Modem (MSM) handles the voice
processing/compression for microphone, receiver (earpiece) and speaker signals.
CDMA and DFM processors handle CDMA operation and control the radio chip of
RFT6122 and RFR6122 through analog interface along with other digital control pins.
The RFT6122 and RFR6122 provide direct conversion of RF signal (zero IF)
architecture to support the CDMA2000 1X standard. The PM6610 controls the power
management for baseband & RF system, and battery charging algorithm.
The baseband architecture supports the power-saving function called “sleep mode”.
Sleep mode shuts off the voltage-controlled temperature-compensated crystal
oscillator (TCXO), which is used as the system clock source for both the RF and the
baseband. During sleep mode, the system runs from a 32 kHz crystal and all the RF
regulators (VREG_RFTX, VREG_RFRX) are off. The sleep time is determined by
network parameters. Sleep mode is entered when both the Mobile Station Modem
(MSM) and its internal DSP are in standby mode and the normal TCXO clock is
switched off. The mobile terminal is awakened by a timer running from this 32 kHz
clock supply. The period of the sleep/ wake up cycle (slotted cycle) is 1.28N seconds,
where N=0, 1, 2, depending on the clot cycle index.
The mobile terminal supports standard Nokia 2-wire and 3 wire chargers (AC-3, AC-4,
DC-4, AC-5, ACP-12, AC-1). However, the 3-wire chargers are treated as 2-wire
chargers. The PWM control signal for controlling the 3-wire charger is ignored. The
MSM and PM energy management software control the charging.
BL-4C (820 mAh) lithium-ion battery is used as the main power source.
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Baseband and RF Architecture
Figure 1: Baseband and RF Block Diagram
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Figure 2: Power Distribution
Power Up and Reset
The PM6610 ASIC controls the power up and reset. The baseband (MSM) can
power up in the following ways:
 Pressing the Power button, which means to ground the KPADPWR_N pin
(“PHONE_ON” net in schematic) of the PM.
 Connecting the charger to the charger input.
After receiving one of the above signals, the PM will start to enter reset mode. The
watchdog starts, and if the battery voltage is greater than its threshold, (3V), a 6ms
delay starts to settle MSM. After this delay elapses, the VERG_MSMC regulator is
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enabled. Then, VERG_MSMP, VERG_MSMA & VERG_TCXO regulators are
enabled in sequence after MSMC. There is a 120us (4 Sleep_Clocks) delays
between each regulator’s turn on. The RESET_N signal (from PM6610 pin
“PON_RESET_N” to MSM6025 pin “RESIN_N” in schematic) holds low for another
20ms and is sent to MSM. Resets are generated for the MSM’s internal MCU and its
internal DSP, and MSM sends TCXO_ON signal to PM (“TCXO_EN” pin) to enable
TCXO. After RESET_N goes high, MSM holds PS_HOLD at low state for 200ms and
then drives PS_HOLD to high state. This will keep all regulators at ON state in
order to complete this power on sequence. PHONE_ON key can be released after
PS_HOLD goes high.
The RESOUT_N from MSM is used to reset flash memory during power up and to
put the flash memory in power down during sleep mode. All baseband regulators are
switched on when the PM is powered on. The MSM’s internal watchdog runs and
resets during normal operation. If the watchdog expires, it will generate a reset signal
to reset to MSM status. Then, MSM drives RESOUT_N low to reset flash memory.
MSM can generate (software control MSM GPIO8) BACKEND_RST_N signal to
reset backend IC.
Backend IC can generate LCD_RST_N to reset LCD. Backend IC can generate
CAM_RST signal to reset camera module.
Figure 3 represents the PM start-up sequence from reset to power-on.
Figure 3: Power-on & off sequence and timing
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Power Up
The mobile terminal can use the power key and a charger to power up.
Power Key
When the power key is pressed, the PM enters the power-up sequence. Pressing the
power key causes the KPADPWR_N pin (“PHONE_ON” net in schematic) to GND.
The power key is directly connected to the PM. This means that when the power key
is pressed, an interrupt will be generated to the MSM in order to power on the MCU.
The MCU reads the PM IC’s interrupt register and notifies that it is a KPADPWR_N
interrupt. If the power key does not indicate a valid power-on situation, the MCU
powers off the baseband.
Charger
Charging is controlled by start-up charging circuitry in order to detect and start
charging in case the main battery is empty and the PM has no supply.
External supply source is detected
If a valid source is applied to VCHG (pin 1 of PM IC, “VEXT_DC” net) and the battery
voltage of VPH_PWR exceeds PM’s valid UVLO (2.5V) threshold, the power-on
sequence of PM is initiated and enables its internal regulators. UVLO is the minimum
voltage required for PM6610 operation. If the entire power-on sequence is successful,
the appropriate interrupt from PM will be sent to the MSM. Once the battery voltage
rises above 3.0V (min. MSM operation voltage), code start running on MSM. The
MSM reads PM registers to identify the power source and whether battery charging
is required. If a valid supply voltage is applied while the PM IC is on, the power-on
sequence is skipped. A charging sequence will then be initiated.
Power Off
While the PS_HOLD signal from the MSM is high, and the PM IC is in one of its
power-on states. Under this condition, the PM continually monitors three events that
could trigger a power-off sequence:
 The MSM drives the PS_HOLD signal low responding to the pressing of the
keypad power button.
 Battery voltage drops below power off threshold (Battery voltage < 3.3 V).
 The PM IC die temperature exceeds its “severe” over-temperature threshold.
Power Consumption and Operation Modes
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Power-off Mode
In power-off mode, power (VPH_PWR) is supplied to the PM6610, RF PA, vibrator,
audio amplifier, keypad backlight LED, LCD backlight booster, flash light booster and
regulator for camera. During this mode, the current consumption is approximately
800 uA.
Sleep Mode
The mobile terminal enters sleep mode only when MSM makes the request to
PM6610 through the SBI bus. PM then enters Power Saving Mode, and the
VREG_MSMC VREG_MSMP regulators remain in power-on stage. The 32.768 kHz
crystal is enabled. TCXO buffers are off. All other functions and regulators are
controlled individually via SBI and are typically disabled for minimum power
dissipation.
It exits the Sleep mode either by the expiration of a sleep clock counter in the
PM6610 or by some external interrupt (generated by a charger connection, key press,
headset connection, etc.). The TCXO is shut down in sleep mode and the 32.768
kHz sleep clock oscillator is used as a reference clock for the baseband.
Active Mode
In active mode, the mobile terminal operates normally. It scans channels, listens to a
base station, transmits and processes information. There are several sub-states
under the active mode. Depending on the mobile terminal’s current state, there are
states such as burst reception, burst transmission, etc.
In active mode, this is a normal operating mode for PM6610 IC. VREG_MSMC,
VREG_MSMP, VREG_MSMA, VREG_RUIM, VREG_RFRX, VREG_RFTX, and
VREG_TCXO regulators are all turned on. TCXO oscillator is enabled, and TCXO
buffers are turned on. All other functions and regulators are controlled individually via
SBI.
Charging Mode
Charging mode can function in parallel with any other operating mode. A BSI resistor
inside the battery pack indicates the battery type/ size. The resistor value
corresponds to a specific battery capacity. The PM measures the battery voltage,
temperature, size, and charging current.
Charger control block inside the PM controls the charging current delivered from the
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charger to the battery and mobile terminal. The maximum battery voltage is limited
by turning the PM switch off when the battery voltage reaches 4.2 V. The charging
current is monitored by measuring the voltage drop across a 0.1 ohm resistor.
Power Distribution
In normal operation, the baseband is powered by the mobile terminal‘s battery pack.
The battery pack consists of one lithium-ion cell with a capacity of 820 mAh and
safety and protection circuits.
The PM6610 IC controls the power distribution to the whole mobile terminal, which
includes the baseband and the RF regulators, but excludes the RF power amplifier
(RF PA) RF power amplifier drains power from the battery directly. The battery
provides power directly to the following parts of the system:
 PM6610
 RF PA
 Vibrator
 Keyboard & LCD backlights
 Audio Amplifier
 Flash light
 Regulator for camera
The heart of the power distribution is the power control block inside the PM6610. It
includes all the voltage regulators and feeds the power to the entire system. The
PM6610 handles hardware power-up functions so that the regulators are not
powered on and the power up reset (PURX) is not released if the battery voltage is
less than 3 V.
The baseband is powered by the following PM6610 regulators:
Regulator Rating
Current Voltage Notes
MSMC 150 mA 1.88 V Always enabled except during power-off mode
MSMA 150 mA 2.60 V Enabled only when the system is powered on
(Off during sleep and power-off modes)
MSMP 150 mA 2.95 V Always enabled except during power-off mode
RUIM 150 mA 3.00 V Enabled only when RUIM card is used
TCXO 50 mA 2.85 V Enabled only when the system is powered on
(Off during sleep and power-off modes)
Table 1: Baseband Regulators
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Table 2 includes the PM6610 regulators for the RF.
Regulator Rating
Current Voltage Notes
RFRX 150 mA 2.65 V Enabled when the transmitter is on
RFTX 150 mA 2.65 V Enabled when the receiver is on
Table 2: RF Regulators
Clock Distribution
The MSM derives its internal clock from two clock inputs, TCXO and SLEEP_CLK.
The main clock signal for the baseband generates from TCXO.
(Temperature-compensated crystal oscillator). The MSM’s TCXO clock input
supports the frequency 19.2 MHz. An integrated PLL and digital divider inside the
MSM are used to create the required clock for the system.
The SLEEP_CLK provides a 32.768 kHz clock source to drive the MSM controller
into sleep mode. At this mode, most of the MSM is powered down and the TCXO is
disabled.
The PM includes several clock circuits (Figure 4), whose outputs are used for
general housekeeping, MSM and RF functions within the mobile terminal system.
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Figure 4: TCXO & SLEEP_XTAL Block Diagram
TCXO
The MSM device integrates a phase-locked loop from the TCXO clock input.
The PM optimizes TCXO operation that enables and disables appropriate circuits in
the proper sequence. The controller is enabled by the TCXO_EN signal from the
MSM. When the selected transition occurs at TCXO_EN, the controller quickly
enables the TCXO regulator and the input buffer, and begins counting SLEEP_CLK
pulses. Within an initial power on period, the TCXO will be stabilized to its own
calibrated frequency. This initial period, in units of 32.768 kHz clock pulses, is
programmed into a timer within the controller. When the timer expires, the output
buffer is enabled. It synchronizes with the TCXO input such that the TCXO_OUT
(MSM_TCXO in schematic) signal is glitch free, only valid TCXO pulses are output.
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Figure 5: TCXO Enable Timing Diagram
The input buffer (TCXO_IN) accepts sinusoidal or square wave signals at or near
19.2 MHz. The input buffer (TCXO_IN) is powered from the TCXO regulator while
the output buffer is powered by VREG_MSMP.
The regulator of TCXO is turned off after the TCXO_EN signal is removed. Upon
power-up, the PM defaults to this SBI-controlled mode with the TCXO defaulted on.
This assures the MSM will always have a clock available immediately at power-up
even if TCXO_EN is low.
TCXO waveform (19.2MHz)
Figure 6: TCXO Timing at 250C
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SLEEP crystal circuit for 32.768 kHz
The 32.768 kHz crystal oscillator is the primary SLEEP clock source when TCXO
clocks are disabled to save power.
Figure 7: Sleep CLK Block Diagram
The 32.768 kHz crystal oscillator signal is generated by an external crystal , which is
supplemented by a PM internal inverter and buffer.
The crystal oscillator continues to run as long as a valid supply is present, even
when the PMIC is powered down. This provides a continuous and accurate 32.768
kHz source. The oscillator halts when power from the external supply and main
battery are removed.
The PM includes a circuit that continually monitors the crystal oscillator signal. If the
crystal stops oscillating, the PM automatically switches to the RC oscillator and
sends an MSM interrupt. Narrow pulses at the SLEEP_CLK output may occur during
this switchover. The crystal oscillator dissipates little power, adjusting its bias current
to the minimum required to maintain oscillation.
SLEEP Clock waveform (32.768KHz)
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Figure 8: Sleep_CLK Timing at 250C
SBI CLK Interface
A 9.6 MHz clock signal is used for DBUS, which is used by the MSM to transfer data
between the PMIC and MSM6025.
Figure 9: MSM to PM SBI Timing at 250C
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The system clock is stopped during sleep mode by disabling the VREG_TCXO.
The TCXO is turned off by the PMIC regulator, which is from MSM’s TCXO_EN
output signal.
Backend IC and Camera Module Clocks
Figure 10: backend IC and camera module clocks
Backend IC (U200) uses external 13MHz crystal (Y210) and internal PLL to generate
internal clocks. Backend IC provides 24MHz clock to camera module. Camera
module uses the 24MHz clock to generate 12MHz pixel clock.
Flash Programming Error Description
This table describes the error condition during Flash memory downloading to the mobile
terminal.
Description Not Working Properly
Packet Checksum fail ERR: CRC invalid
Erase fail Unable to erase device
Write fail Write unsuccessfully
Figure 11: Flash Programming Error Description
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Charging Operation
Battery
Thumper uses a Lithium-Ion cell battery with a capacity of 820 mAh. Inside the
battery, there is a resistor connected between BSI pin and GND pin for battery ID,
MSM reads the BSI pin (via VBATT_ID signal in schematic) to identify the battery
size. Different charging algorithms will be used for different battery sizes.
Figure 12: BL-4C battery pack pin order
Charging Circuitry
The PM6610 IC charge control is dependent on the charger type and the battery size.
External components are needed for electromagnetic compatibility (EMC), and
transient protection of the input to the baseband module. The charger’s DC input is
through the dc-jack connector. This mobile terminal supports AC-3,AC-4, DC-4,
AC-5, ACP-12 and AC-1 chargers.
Figure12:ChargingCircuitry
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Charger Detection
Connecting a charger creates a voltage on the VCHG (“VEXT_DC” net in schematic)
input of the PM6610. Charging starts when the PM6610 detects the VCHG input
voltage level above 3.3V (Min. working voltage of VCHG pin).
The VCHG signal of PM is generated to indicate the presence of the charger for the
software. The power management (PM) software controls the charger identification/
acceptance. The charger recognition is initiated when the EM software receives
a ”charger connected” interrupt. The algorithm basically consists of the following
three steps:
1. Check that the system current (the collector current of PNP transistor) is within
safety limits.
2. Check the power consumption of PNP transistor is within safety limits.
3. Check that the charger is within the charger window (voltage and current). If the
charger is accepted and identified, the appropriate charging algorithm will be
initiated.
Figure 13: Mobile terminal DC Jack power input circuit.
Figure 14: PNP Charging Control Circuit.
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Charge Control
In active mode, charging is controlled by the PM6610’s digital part. Charging voltage
and current monitoring are used to limit charging into a safe area. The PM6610 has a
MaxPower protection limit at PNP transistor to cut-off charger.
Cut Off MaxPower = 600mW
The PM6610 limits the charging voltage to MaxVoltage.
MaxVoltage= 4.25V
The PM6610 limits the total system current (the collector current of PNP transistor)
by limiting the maximum power of PNP transistor charge.
Audio
The audio control and processing is provided by the MSM which contains the audio
codec, the MCU and DSP blocks. These blocks handle and process the audio data
signals. The baseband supports 2 microphone inputs and three receiver (earpiece)/
speaker outputs.
Figure 15: Audio Sending Direction Block Diagram
MIC+ & MIC- are used for the mobile terminal's internal microphone. JACK_MIC+ &
JACK_MIC- are used for headsets.
The internal microphone (MIC+/-) is differential AC connection to the MSM
(MIC1P/N). The headset microphone is single-ended AC connection to the MSM
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(MIC2P/N).
The MICBIAS output (“MIC_BIAS” signal) is used for internal microphone bias to
provide 0.2 mA of current at 1.8 Volts DC.
VDD_MSMP (2.95V) regulated voltage from PM IC is used for headset microphone
bias.
(U100)
Figure 16: Audio Receiving Direction Block Diagram
RECEIVER+ & RECEIVER- (MSM pins EAR1OP & EAR1ON) differential outputs are
used for the mobile terminal's internal receiver. HPH_L (MSM pin EAR2)
single-ended output is used for accessory external headset. AUXOP & AUXON
differential outputs are used to drive external loudspeaker via external audio power
amplifier (U100).
The output power for the differential (EAR1O) output is typically 35 mW for a
full-scale +3 dBm0 sine wave into a 32 ohm receiver.
The output power for the single-ended (EAR2) output is typically 8.8 mW for a
full-scale +3 dBm0 sine wave into a 32 ohm receiver (earpiece).
The output power for the auxiliary (AUXO) output is typically 1.87 mW for a full-scale
+3 dBm0 sine wave into a 600 OHM load.
Keypad
The mobile terminal uses eight blue light-emitting diodes (LEDs) for keypad
illumination. MSM GPIO42 is used to turn on/off these LEDs.
MSM uses GPIO57 ~ GPIO66 (KYPD0, KYPD1, KYPD3, ~ KYPD17) to do keypad
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