Debug Board v2

Revision as of 20:06, 15 February 2007

Architecture of the second version of the Neo1973 debug board:

Annotated PCB Photograph

Overview

Key components

USB Hub

This bus-powered hub

• attaches to the laptop using its upstream port
• attaches to the FT2232-for-JTAG using downstream port 1
• attaches to the FT232-for-serial using downstream port 2
• attaches to the phone using downstream port 3

Using the hub, you can have access to the phone, JTAG and serial simultaneously, through a single USB cable.

You can actually even charge the phone (100mA slow charge) using that downstream port.

For the hub, we can use the TUSB2046B chip, which is very common and easily available.

JTAG using FT2232

Basically, we integrate a USB-JTAG adaptor similar to the [Amontec JTAGkey-tiny]. The actual reference design that we used (Thanks to Joern!) can be found at http://www.joernonline.de/dw/doku.php?id=en:projects:oocdlink

This provides us full JTAG debugging, at about 150times the speed of the wiggler

The actual JTAG port is connected with

• the phone (via debug flex cable)
• A separate 20-pin header using standard ARM-JTAG pinout
  • this allows the user to use this device as JTAG adaptor even for other arm-based devices

Serial Port

Instead of replicating a true RS232 port, we use a USB serial converter chip, such as the FT232 or the PL2303. It is attached (without level shifter) to the phone's debug port.

As it turns out, we can even use the second port of the FT2232 simultaneously with the JTAG. So no extra FT232 or PL2303 is required.

Tri-State Serial Port

The serial port needs a tri-state driver, since it is both connected to the GSM modem AND to the debug board. We drive the tri-state driver by an inverted GSM_EN signal (pin 7 on FPC connector).

Usage Instructions

Preconditions

FT2232D EEPROM

Your Debug Board contains a small serial EEPROM which must be flashed correctly. FIC has done that for you, in case you have officially been supplied with the board. However, if you are one of the early adopters, the configuration and USB vendorID / productID might have not yet been set correctly.

In order to do so, you can use the ftdi_eeprom program from http://www.intra2net.com/de/produkte/opensource/ftdi/

A suitable EEPROM config file will be posted here soon.

Hardware connection

• Connecting Neo1973 with Debug Board v2

History

We previously had Debug Board v1

Changes from v1 to v2

• get rid of ethernet
  • we don't need it, and
  • we especially don't want a 40pin parallel 66MHz bus going between two pcb's
• get rid of 7-segment LED displays
  • not really needed. We have a serial port
  • could be replaced by one or two GPIO LED's
• get rid of built-in wiggler
  • nobody has a parallel port on the laptop these days
• get rid of li-ion battery (including charger)
  • the device can be fully usb powered by the laptop