mr.shahalom Admin
Posts : 390 Join date : 2011-09-02 Age : 25
| Subject: Signal/Part descripions Sat Nov 19, 2011 4:07 pm | |
| Signal/Part descripions Descriptions:
---this not ready yet - but if I tell you sth wrong ,pls post in this threat ----
One of the difficultest errors you will try to repair is a dead phone. Different Hard- and Soft probs can be the reason.
To repair a dead phone, you should have some knowledge about the important components that a phone need to work.
What is a mobile phone:
Every mobile phone is a little computer,
it has a CPU (Central-Processing-Unit) a RAM (Random-Access-Memory) a ROM (Read-Only-Memory - today this ROM is mostly placed with a Flash), and periphical devices: differnt I/O interfaces like keyboard, displsy (keyboard & display together sometimes called "MMi" [MenMashineInterface]) , serial Interface (COM,USB), IrDa, Bluetooth, a sound interface, and really important: A RF interface to communicate with a Basestation.
What is a CPU: A CPU is a couple of transistors that do nothing without them saying what to do.
What is a Ram? A RAM is a couple of transistors that do nothing without them saying what to do. A RAM is to storing information tempoary, you can write content in it or read out the content. A RAM loose all its informaton if the power supply is lost.
What is a ROM? A ROM contains the Software for the CPU. This software tells millions of transistors what to do. A ROM needs no power to hold the information in it.
This three compontnts are connected via a Databus and a Adressbus. And they have their own adress-ranges.
What needs the processor to work:
Power supply of couse... the most mobile phones has a powersupply IC. This IC delivers most of the in a mobilephone used voltages - but not all. (Sometimes this component is called ASIC [Aplication-Specific-Integrated-Circuit] what only means, that this IC is only developt for this application.) Most of the integrated circuits in those IC are standard voltage regulators (VREG) such as a 7803 or sth else controled by a little processor. But there are some other components init. E.g. a I2C Bus connection, a I2S connection, a PA for the speakers, battery charge control, a reciver for the watchdog signal from the processor. 3 switch on sensors (on/off1-KB7, on/off2-RTC_INT , Power from charger) a.sth.e.
Some Important parts of the Power Supply Asic:
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WA_DOG: (watchdog)
Status: Switch on: important Network : unimportant
If the processor halt 'couse of an error or a HLT-command, it terminates the watchdog. If there is no watchdog signal from the processor the ASIC shutdown atfer one second. Watchdog signal is a ca. 1 Hz digital signal.
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I2C Bus:
Status: Switch on: unimportant Network : unimportant
This bus is to control the powersupply IC by the processor. The processor can tell the ASIC to switch on and of single voltages (but this option is unused) - and this bus can be used to tell the processor measured voltage values and sth. else.
--
I2S Bus:
Status: Switch on: unimportant Network : unimportant Sound : important
A I2S bus can transport sound in cd-audio quality from processor to ASIC. Mostly used for playing MP3 sound.
--
RTC_INT(erupt):
Status: Switch on: unimportant, but can be used to switch on the mobile. Network : unimportant
is to switch on the ASIC by the GOLD. If the mobile is switched off, and a battery is insertet, the clock (RTC) is runing well, and if there is a alarmtime programmed, RTC_INT goes H at alarmtime - to switch on your mobile and waking up you....
--
RESET:
Status: Switch on: important Network : unimportant
Reset is a 2,5V H Level that comes up after 250ms (newer models: 167ms) after switching on the powersupply. To control the resettime there is a capacitor or a resistor assemled on the R_REF pin to GND. The reset-signal is very important for all logical components. If reset stay L the locical components stay in reset mode. The components run when reset goes H. The delaytime is important - becouse all components should reset during switch on. But first the supplyvoltages must be up.
Reset on L: executes a reset. If you connect RESET to GND during your mobile is working, it will restart.
If reset stay on L-level becoue shortconnection or its open: The mobile wont switch on.
--
R_REF:
Status: Switch on: important Network : unimportant
Reset reference for reset delaytime at startup. This track has only a capacitor or a resistor connected to GND.
-----------------
different voltages:
in some series all voltages are named VREG_[component Name] VREG_A or VREGA - that means: VoltageRegulater_Analog VREG_RF1 or VREG_RF2 :VoltageRegulator_RadioFrequency1 or is simply numbered e.g. VREG1, VREG2 ect.
--
CCVCC (VREG_CC)
Status: Switch on : unimportant Network : unimportant SIM : Important
is not importatnt for switching on, but what you doing with a phone that cant read a SIM-Card? - Only SOS Call.
ChipCard suply voltage. It ist to suply your SIM-Card In very very old Models 5V, in very old Models 3V and 5V, in old models 3V and 1,8V, in newest Models only 1,8V.
--
VCC2,8V / VDD_RF1 / VREG_RF1 : - in C60 and MC60 unused but enabled
Status: Switch on : unimportant Network : important Stanbytime : TP840 problem (C60/MC60)
Own voltage-regulator for the RF IC and PLL's arround it. VCC 2,8V is controled by the SLEEPQ signal. In older models the VCC2,8 voltage regulator was a single part. If no 2,8V there becouse short connection or missing SLEEPQ your mobile says: "No Network"
--
VCC_SYN (2,8V) (VDD_RF2, VREG_RF2) - In C60/MC60 used for the complete RF part (but not PA).
Status: Switch on: important Network : important
- Supplys the very important 26MHz mainclock circuit. (in older models only the supply for the 26MHz/13MHz mainclock, and a single part) This Voltage is controled by the:
--
VCXO_EN(able) / VCOEN / VCXOEN_uC signal
Status: Switch on: important Network : important
- this makes the processor able to switch off its mainclock to go in sleepmode and to sleep with the 32,768 KHz RTC - it is to save battery energy.
If missing VCC_SYN becouse of shortconnection or missing VCXO_EN the mobile won't switch on.
--
VDD_RTC / VRTC
Status: Switch on: important Network : unimportant
This voltage is for the CPU integrated Real-Time-Clock. Outside of the processor is a 32KHz cristal, mostly covered in a plastic case (named Z100,Z101,Z171 in shematics). This voltage comes up as a battery is inserted. It is buffered with a 10ยต capacitor that makes you able to place the battery without loosing date and time. It delivers also the H-Level for the ON/Off key via a resistor to KB7.
If missing this voltage there is no reaction and no current-consumption while trying to switch on via On/off key. The mobile seems completly dead - only charging possible.
--
Batt+
Directly connected to Powersuply ASIC, PA, IrDa and some standalone voltageregulators.
--
VCC2,9V (older Models)
Status: Switch on: important Network : important if single tracks to GOLD are damaged.
Supply for GAIM, DSP, Halfrate-CoPro (very old models) , and switches, EMI Filter, IrDa together with Batt+ and sth else. But now GAIM and Copro are itegrated in the GOLD. GAIM is the part to control the RF timing and A/D D/A converter to transmit/recive speech data via GSM. Supply for RAM and Flash (older Models)
In newer Models: Supply for Flash in WriteMode (else 1,8V in NormalMode) Supply for in Gold integrated parts like GAIM.
VCC2,9V (in newest phones): missing
--
VDD_A(nalog)
description later
--
VDD_Dig(ital)
description later
--
1,5V
description later
--
a functional main Clock (Reference Oscillator, RefOsc) (26MHz / 13MHz) of couse.
and a functional Data-/Adressbus:
The Adressbus: The more memory the wider the adressbus. Today 24Bit wide. The adressbus is to adress memory a******* - this can be RAM or ROM a*******. If one track in the adressbus is shortconected to another or to GND or a supplyvoltage or is simply open, one or two bits on adressbus are wrong - and also the adress shown on the adressbus is wrong. So the data on the databus comes from wrong adress, and the processor recives garbage as a program to run.
-The processor halt. -No WA_DOG sent. -The mobile switch off.
The Databus: In Mobile phones mostly 8 Bit wide. (newer models 16Bit) The databus is to read/write data to the on the adressbus seen memory adress. To decide reading or writing data from/to a memoryadress mostly a write/read track is used (WR,RD). The state of this tracks H or L says the components reciving or writing data via the databus from/to the adress actualy seen on the adressbus. The databus can be used to expand the adressbus, and the adressbus can be used to expand the databus. Here is a track too, wich state decide this.
If one of those tracks are schortconnectet to another or open willt take the same effect as I said upwards.
-The processor halt. -No WA_DOG sent. -The mobile switch off.
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mr.shahalom Admin
Posts : 390 Join date : 2011-09-02 Age : 25
| Subject: Re: Signal/Part descripions Sat Nov 19, 2011 4:08 pm | |
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mr.shahalom Admin
Posts : 390 Join date : 2011-09-02 Age : 25
| Subject: Re: Signal/Part descripions Sat Nov 19, 2011 4:09 pm | |
| Can you descript error from power comsumption (shown an power supply usage) of a dead phone? I think we can 'generally' "see" error from there. Correct me if I'm wrong. NB: very good post! | |
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| Subject: Re: Signal/Part descripions | |
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