Developer Board Hardware FAQ

Q - The specified memory is 2M flash and 8M ram. Can it be changed to bigger size such as 4M flash and/or 16M ram?
A - The maximum flash size is 4M and the maximum RAM size is 8M. If you want 4M flash on a small number of units the easiest way is to exchange the flash by hand. For larger volumes it may be possible to get a larger flash mounted at the factory.

Q - Is the general IO available on the developer board?
A - The I/O pins on PA and PB is connected on various places:

PA0 - O - /SERIAL_INIT, used to get correct initial values on the serial ports
PA1 - I - Test button. Button accessible on the card
PA2 - O - Status LED
PA3 - O - COM2 enable
PA4 - O - Connected to DTR on COM2
PA5 - I/O - Connected to RI on COM2
PA6 - I - DSR on COM2
PA7 - I/O - CD on COM2
PB0 - I/O - EEPROM/TK data
PB1 - O - EEPROM/TK clock
PB2 - O - EEPROM/TK select
PB3 - O - COM1 enable
PB4 - O - DTR on COM1
PB5 - I - RI on COM1
PB6 - I - DSR on COM1
PB7 - I - CD on COM1

This means that PA4-PA7 and PB4-PB7 can be used for external signals by connecting the external signals to the serial ports. PA4-PA7 and PB4-PB7 is accessible as 3.3V signals on X4 and X18 as well (see pinout.txt). You can use the output signals, but not the input signals without disabling the RS-232 driver chips first (otherwise you will compete with the RS-232 driver output for the input signals). RI and CD on COM2 can be used in both directions (PA5 and PA7). The original design supported disabling of the RS-232 drivers with PA3 and PB3, but due to the low availability of the particular RS-232 driver that supported this (ADM3311) this is not possible (the second source we use: DS14C335, does not have that feature, so to get the product out we decided to skip this feature. A couple of resistors must be moved/added to enable the feature if an ADM3311 is mounted). The parallel ports can be used for general purpose I/O as well.

Q - I am considering to use the parallel IO port for IO. Can I assume that the 2 ports available are equivalent to those on the PC (hardware signal level), or I can just emulate the functionality?
A - The parallel ports are 3.3V. This means that they can be connected to equipment under normal circumstances (short cables etc). For longer cables the voltage drop may be to large. Parallel port 0 is equipped with a buffer and an inverter and is suited for connection to a printer. Parallel port 1 has no buffers or inverters and is suitable for connection to other units e.g. a LCD.

Q - I hear that the ETRAX 100LX has a USB interface, but I can't see any USB connecters on the board. What are my options?
A - The developer board doesn't come equipped with USB connectors or USB transcievers, it is however possible to connect these externally without too much trouble. Please have a look at How to add an USB port to your devboard_lx card.