Paraflasher

THIS PROJECT IS STILL UNDER CONSTRUCTION

Welcome to The Paraflasher Project. Open source hardware for developing open source software.

The project is maintained by Joseph Smith.

Overview

The Paraflasher (Parallel Port Flasher) 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 Paraflasher is based on an old LPC programmer built to flash LPC chips on the xbox, the LPC^2 (Low Parts Count LPC Programming Cable). The Paraflasher 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

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  Top

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  Ugly Bottom

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  Front

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  Right

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  Left

Components

Component	Recomended Specs	Part Used	Price Paid ($US)
DB25 Connector	Type:D Sub No. of Contacts:25 Gender:Plug Contact Termination:Right Angle Through Hole	ITW McMurdo DB25PNF	3.82
10-Bit FET Bus Switch With Level Shifting	Package/Case:SOIC (DW) No. of Contacts:24 Supply Voltage (Min/Max):4.5V/5.5V Supply Current (Max):3uA	Texas Instruments SN74CBTD3861DW	0.64
SOIC To DIP Adapter	Package/Case:28-DIP No. of Contacts:28 SOIC Mounting Type:Surface Mount DIP Mounting Type:Through Hole DIP Pitch Spacing:2.54mm	MIND_TEK SOIC surface mount PCB adaptor	1.60
Octal Buffer	Package/Case:20-DIP IC Generic Number:74HC244 Supply Voltage Max:6V Mounting Type:Through Hole	STMicroelectronics M74HC244B1R	0.40
Header Connector	Gender:Shrouded Header No. of Contacts:10 Pitch Spacing:2.54mm No. of Rows:2	Molex 70246-1001	0.87
USB B Connector	Gender:Receptacle No. of Contacts:4 Connector Mounting:PC Board Contact Termination:Right Angle Through Hole	Adam Technologies USB-B-S-RA	0.39
PTC Resettable Fuse	Hold Current:0.25 Amp (250mA) Trip Current:0.5 Amp (500mA) Current Rating (Max):40 Amps	Littelfuse 60R025XU	0.26
Blue LED	Bulb Size:5mm LED Color:Blue Forward Current:20mA Forward Voltage:3.4V	OPTEK Technology OVLFB3C7	0.74
LED Resistor	Resistance:200 Ohms Power Rating:2 Watts Material:Metal Film	Vishay/Dale CPF2200R00FKE14	0.42
Linear Voltage Regulator	Voltage Regulator Type:LDO Linear Output Voltage Max:3.3V Package/Case:3-TO-220 No. of Pins:3	National Semiconductor LM1084IT-3.3/NOPB	2.83
2 Tantalum Capacitors	Capacitance:10 uF Tolerance:10% Voltage Rating:10 Volts Termination Style:Axial Product:Tantalum Solid High Reliability	Vishay/Sprague 173D106X9010VE3	0.56 X 2
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 Roth Electronik 26M2198	Already had (5.93)
Hook-Up Wire	Conductor Size AWG:30 Jacket Material:Polyvinylchloride (PVC) No. Strands x Strand Size:Solid Conductor Material:Copper	About a foot of Belden 9978 013100	Already had (Spool of 100ft 22.61)
Small Power Wires	Red wire for 5V Two Orange wires for 3.3V		Already had

The Circuit Explained

Data Circuit

SN74CBTD3861

The Paraflasher is connected to the PC’s Parallel port via a DB25 Parallel extension cable and is run in SPP mode. The 10-Bit FET Bus Switch With Level Shifting is connected to data lines D0 – D7 convert the data signals from 5V to 3.3V needed by most if not all flash chips. The 74HC244 is an advanced high-speed CMOS Octal Bus Buffer that acts as a simple signal buffer between the parallel port and the flash chip. The parallel port data lines D0, D1, and D2 are used for driving the control signals RST/RP, LCLK/CLK, and LFRAME/FWH4. Data line D3 is used as a Write Protect signal connected to pin 1G (Output Enable Input) of the M74HC244 and should be driven high at all times except during write operations where it should be driven low. The parallel port data lines D4, D5, D6, and D7 are buffered and used for write operations (sending data) over the corresponding LAD/FWH[0], LAD/FWH[1], LAD/FWH[2], and LAD/FWH[3] lines. The LAD/FWH[0], LAD/FWH[1], LAD/FWH[2], and LAD/FWH[3] lines are also connected to the Error, Ack, PE, and SELIN lines. They are also buffered and feed back to the parallel port to be used for read operations (receiving data) or can be used for verifying data that is being written (sent) in real time.

M74HC244B1R

Signals Simplified

Parallel Port	To LPC Signal	To FWH Signal
D0	RST	RP
D1	LCLK	CLK
D2	LFRAME	FWH4
D3	Write Protect	Write Protect
D4	LAD0	FWH0
D5	LAD1	FWH1
D6	LAD2	FWH2
D7	LAD3	FWH3
/Error	LAD0	FWH0
/Ack	LAD1	FWH1
/PE	LAD2	FWH2
/SELIN	LAD3	FWH3

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 and it works pretty slick. The Paraflasher 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), figure out what tripped the fuse and fix it, 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.

If there are any inconsistencies or you would like to elaborate on anything above, please feel free.

Daughter Boards

TODO

Software

The core of the Paraflasher uses ppdev user-level device driver for Linux.

TODO: flashrom???

Support

TODO

Conclusion

TODO