Difference between revisions of "Paraflasher"

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(The Circuit Explained)
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The Paraflasher Project has now moved to flashrom: [http://www.flashrom.org/Paraflasher http://www.flashrom.org/Paraflasher]
Welcome to '''The LPCflasher Project'''. Open source hardware for developing open source software.
The project is maintained by [[User:linux_junkie|Joseph Smith]].
The LPCflasher is low-cost simple flash programming device. It can be used to flash a variety of LPC flash chips and firmware hubs (FWH). The hope is someday it will also be able to support SPI chips. It is also meant to be modular so you can flash a variety flash chip packages. The LPCflasher is based on an old LPC programmer built to flash LPC chips on the xbox, the [http://rex.xbox-scene.com/LPC2/LPC2.html LPC^2 (Low Parts Count LPC Programming Cable)]. The LPCflasher is not for sale, it is meant for that "do-it-yourself" kind of person. Although if the project becomes popular, bare PCB's could be produced and sold at cost. Anyone with novice to moderate soldering skills can build one.
'''Other Pictures'''
Image:LPCflasher_bottom.jpg|Ugly Bottom
{| border="0" cellpadding="2"
|- bgcolor="#6699ff"
! Component
! Recomended Specs
! Part Used
! Price Paid ($US)
|- bgcolor="#dddddd"
! DB25 Connector
*Type:D Sub
*No. of Contacts:25
*Contact Termination:Right Angle Through Hole
| [http://www.farnell.com/datasheets/78807.pdf ITW McMurdo DB25PNF]
| 3.82
|- bgcolor="#eeeeee"
! 7 Resistors
*Power Rating:250mW (1/4W)
*Material:Metal Film
| [http://www.irctt.com/pdf/CMF.pdf IRC / TT Electronics CMF1/41001FLFTR]
| 0.05 X 7
|- bgcolor="#dddddd"
! Octal Buffer
*IC Generic Number:74HC244
*Supply Voltage Max:6V
*Mounting Type:Through Hole
| [http://www.st.com/stonline/books/pdf/docs/8024.pdf STMicroelectronics M74HC244B1R]
| 0.40
|- bgcolor="#eeeeee"
! Header Connector
*No. of Contacts:16
*Pitch Spacing:2.54mm
*No. of Rows:2
| [http://www.molex.com/catalog/pdf/MX70280.pdf Molex 10897162]
| 1.19
|- bgcolor="#dddddd"
! USB B Connector
*No. of Contacts:4
*Connector Mounting:PC Board
*Contact Termination:Right Angle Through Hole
| [http://www.adam-tech.com/rick/FinalSingle/CatPg127-134.pdf Adam Technologies USB-B-S-RA]
| 0.39
|- bgcolor="#eeeeee"
! PTC Resettable Fuse
*Hold Current:0.25 Amp (250ma)
*Trip Current:0.5 Amp (500ma)
*Current Rating (Max):40 Amps
| [http://www.littelfuse.com/data/en/Data_Sheets/Littelfuse_60R.pdf Littelfuse 60R025XU]
| 0.26
|- bgcolor="#dddddd"
! Blue LED
*Bulb Size:5mm
*LED Color:Blue
*Forward Current:20mA
*Forward Voltage:3.4V
| [http://www.optekinc.com/datasheets/OVLFx3C7SERIES.PDF OPTEK Technology OVLFB3C7]
| 0.74
|- bgcolor="#eeeeee"
! LED Resistor
*Resistance:200 Ohms
*Power Rating:2 Watts
*Material:Metal Film
| [http://www.vishay.com/docs/31021/cpf.pdf Vishay/Dale CPF2200R00FKE14]
| 0.42
|- bgcolor="#dddddd"
! Linear Voltage Regulator
*Voltage Regulator Type:LDO Linear
*Output Voltage Max:3.3V
*No. of Pins:3
| [http://cache.national.com/ds/LM/LM1084.pdf National Semiconductor LM1084IT-3.3/NOPB]
| 2.83
|- bgcolor="#eeeeee"
! 2 Tantalum Capacitors
*Capacitance:10 uF
*Voltage Rating:10 Volts
*Termination Style:Axial
*Product:Tantalum Solid High Reliability
| [http://www.vishay.com/docs/40019/173d.pdf Vishay/Sprague 173D106X9010VE3]
| 0.56 X 2
|- bgcolor="#dddddd"
! Breadboard PCB
*Min External Height: 50.80mm
*Min External Width: 82.55mm
*Board Thickness:1.5mm
*Pitch Spacing:2.54mm
*Hole Diameter:1mm
| A piece of [http://www.farnell.com/datasheets/98850.pdf Roth Electronik 26M2198]
| Already had (5.93)
|- bgcolor="#eeeeee"
! Hook-Up Wire
*Conductor Size AWG:30
*Jacket Material:Polyvinylchloride (PVC)
*No. Strands x Strand Size:Solid
*Conductor Material:Copper
| About a foot of [https://edeskv2.belden.com/Products/techdata//english/swf/9978.swf Belden 9978 013100]
| Already had (Spool of 100ft 22.61)
|- bgcolor="#dddddd"
! Small Power Wires
* Red wire for 5V
* Two Orange wires for 3.3V
| Already had
==The Circuit Explained==
[[Image:LPCflashersch.jpg|LPCflasher Schematic|600px]]
If there are any inconsistencies or you would like to elaborate, please feel free.
===Data Circuit===
The LPCflasher is connected to the PC’s Parallel port via a DB25 Parallel extension cable and is run in SPP mode. A series of 1K ohms resistors 250mW (1/4W) on data lines D0 – D6 convert the signals from 5V to 3.3v needed by the flash chip. The parallel port data lines D0, D1, and D2 are used for driving the control signals LCLK, LFRAME, and RST. The parallel port data lines D3, D4, D5, and D6 are used for bi-directional data transfers of the corresponding LAD0, LAD1, LAD2, and LAD3 lines. LAD0, LAD1, LAD2, and LAD3 lines are also buffered and feed back to the parallel port /Error, /SELIN, /PE, and /Ack signals. The 74HC244 is an advanced high-speed CMOS Octal Bus Buffer that acts as a simple signal buffer between D0, D1, /Error, /SELIN, /PE, /Ack and the LCLK, LFRAME, LAD0, LAD1, LAD2, LAD3 lines.
===Power Circuit===
I did not like the original power circuit design of using a wall-wart type power supply and a LED as voltage regulator, so I came up with the following. The LPCflasher is powered by USB via a USB printer cable. The jack is a USB type B. All of the grounds from every component requiring a ground is connected together. The +5 VDC from USB is connected to a PTC Resettable Fuse with trip current of 0.5 Amp (500ma). USB v2.0 specifies a maximum of 500mA so this will protect the PC’s USB port from any damage caused by short circuits, etc. If the PTC Resettable Fuse is tripped, disconnect the power source (USB) and wait a few seconds for the PTC Resettable Fuse to cool down and reset. Next I put in a simple LED circuit just for user aesthetics, so you know your getting power from USB. If you want to use a different color LED or if the blue LED is too bright you can adjust the ohms of the resistor. A 5V power line branches off from here and continues to the header to power a 5V flash chip. I went with the LM1084IT-3.3 voltage regulator because it is designed to convert 5V to a fixed output of 3.3V to power the octal buffer and a 3.3V flash chip. Simple and effective. National Semiconductor recommends for a 5V to 3.3v conversion to place a 10 UF Tantalum capacitor on both the input and output lines of the voltage regulator. They recommend using Tantalum capacitors for stability because their equivalent series resistance (ESR) is lowest at any temperature. The 3.3V line powers the 74HC244 octal buffer and continues on to the header to power a 3.3V flash chip.
==Daughter Boards==
TODO: flashrom???

Latest revision as of 15:18, 11 July 2010

The Paraflasher Project has now moved to flashrom: http://www.flashrom.org/Paraflasher