Nokia 7088, RM219 Baseband Description and Troubleshooting

Nokia Customer Care

7088 (RM-219)

Mobile Terminal

Baseband Description and

Troubleshooting

7088 (Flower) Base band 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...................................................9

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 Description.................................................................... 16

Charging Operation................................................................................................ 17

Battery .........................................................................................................17

Charging Circuitry........................................................................................17

Charger Detection........................................................................................18

Charge Control ............................................................................................19

Audio ...................................................................................................................... 19

Keypad ................................................................................................................... 21

Display.................................................................................................................... 21

Camera and Flash Light LED................................................................................. 22

Universal Serial Bus (USB).................................................................................... 22

Accessories............................................................................................................ 24

Charging......................................................................................................24

Headset Detection.......................................................................................24

Data Access.................................................................................................25

UIM CARD.............................................................................................................. 25

7088 (Flower)

Nokia Customer Care Baseband Description and Troubleshooting

Test Points.............................................................................................................. 26

Main Board Top Layer Test Points ...............................................................26

Main Board Bottom Layer Test Points..........................................................27

Sub Board Top Layer Test Points................................................................. 28

Sub Board Bottom Layer Test Points...........................................................29

Troubleshooting...................................................................................................... 30

Mobile Terminal is Dead............................................................................... 31

Flash Memory Faults ...................................................................................32

Power Does Not Stay ON or the Mobile Terminal is Jammed......................33

Charger Faults.............................................................................................34

Audio Faults.................................................................................................35

Display Faults..............................................................................................39

Keypad Faults..............................................................................................40

Keypad Faults..............................................................................................41

Camera Faults.............................................................................................42

Camera Faults.............................................................................................43

7088 (Flower) Base band Description and Troubleshooting

Introduction

The mobile terminal with a CDMA single mode engine (Cellular/ 800) and Qualcomm base band consists of the following ASICs:

 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 base band (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 base band system. ARM7 processor communicates with external memory, backend IC and LCD through local address & memory buses. A QDSP4000 with codec inside the processing/compression for microphone, receiver (earpiece) and speaker signals. CDMA and DFM processors handle CDMA operation and control the radio chip 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 base band & RF system, and battery charging algorithm. The base band 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 base band. 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.

Mobile Station Modem (MSM) handles the voice

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-4B (700 mAh) lithium-ion battery is used as the main power source.

7088 (Flower)

Nokia Customer Care Baseband Description and Troubleshooting

Baseband and RF Architecture

Figure 1: Baseband and RF Block Diagram

7088 (Flower) Base band Description and Troubleshooting

Figure 2: Power Distribution

Power Up and Reset

The PM6610 ASIC controls the power up and reset. The base band (MSM) can be powered up in the following ways:

 Pressing the Power button, which means to ground the KPADPWR_N pin

of the PM (“PHONE_ON” net in schematic).

 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 allow MSM to settle. After this delay elapses, the VERG_MSMC

7088 (Flower)

Nokia Customer Care Baseband Description and Troubleshooting

regulator is 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 turning-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 base band 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.

(PHONE_N)

(RESET_N)

Figure 3: Power-on & off sequence and timing

7088 (Flower) Base band Description and Troubleshooting

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. The MCU reads the status of the KPADPWR_N pin using the PM’s (SBI) control bus. If the KPADPWR_N stays low for a certain time, the MCU accepts this as a valid power-on state and continues the software baseband initialization. If the power key does not indicate a valid power-on situation, the MCU powers off the base band.

Charger

Charging is controlled by the start-up charging circuitry in order to detect and start charging in cases 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 its internal regulators are enabled. 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 starts 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, 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.

7088 (Flower)

Nokia Customer Care Baseband Description and Troubleshooting

Power Consumption and Operation Modes

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 to support the application of camera. During this mode, the power consumption is approximately 200 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, but the VDD_MSMC VDD_MSMP regulators remain in power-on status. The 32.768 kHz crystals are 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 base band.

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. VDD_MSMC, VDD_MSMP, VDD_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 battery ID 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,

7088 (Flower) Base band Description and Troubleshooting

temperature, size, and charging current.

The charger control block situated inside the PM controls the charging current delivered from the 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 base band is powered by the mobile terminal‘s battery pack. The battery pack consists of one lithium-ion cell with a capacity of 700 mAh and safety and protection circuits.

The PM6610 IC controls the power distribution to the whole mobile terminal, which includes the base band 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 following PM6610 regulators power the base band:

7088 (Flower)

Nokia Customer Care Baseband Description and Troubleshooting

Regulator

MSMC 150 mA 1.88 V Always enabled except during power-off mode

Rating

Current

Voltage Notes

MSMA 150 mA 2.60 V 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 2.8 V

Table 1: Base band Regulators

Table 2 includes the PM6610 regulators for the RF.

Regulator

RFRX 150 mA 2.60 V Enabled when the transmitter is on

RFTX 150 mA 2.60 V Enabled when the receiver is on

Rating

Current

Voltage Notes

Enabled only when the system is powered on (Off during sleep and power-off modes)

Table 2: RF Regulators

Clock Distribution

The MSM derives its internal clock from two clock inputs, TCXO and SLEEP Clock.

The main clock signal for the base band 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 Clock provides a 32.768 kHz clock source to drive the MSM controller in 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.

7088 (Flower) Base band Description and Troubleshooting

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 the 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.

7088 (Flower)

Nokia Customer Care Baseband Description and Troubleshooting

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 VDD_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 25

7088 (Flower) Base band Description and Troubleshooting

SLEEP crystal circuit for 32.768 kHz

The 32.768 kHz crystal oscillators 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 available, 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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