
IMPORTANT OPERATING NOTES:
Starting with Rev 2.2, the power system for the programmer is independent
of the power for the radio and backlight. The programmer gets its power
from the USB, while the radio (and backlight) gets its power from the
battery. Therefore, it is now necessary to have your radio powered on via
battery during programming and transfer operations.
Starting with Rev 2.2, the backlight is designed to operate on by default to
make it compatible with all firmware options. However, in doing this it makes
some firmware versions work "backwards". Until a given firmware package
has specific support for the Rev 2.2 board, you may have to program it to be
"off" when you expect the light to be on, and vice versa. In ER9X simply
engage the "inverted backlight" option. In OpenTX, select the "sp22" option
when downloading. Some technical jargon to help other firmware authors:
The light is powered when the 9x outputs a low (zero volt) signal on PB7 (aka
"pin 17") . A high (5v) signal turns the light off. Sending a PWM of varying
duty cycle will dim the light from 0 to 100% (frequency of 400hz if
frequency can be set independent of duty cycle).
Starting with Rev 2.4, we've now included an aux ISP cable. The intention
of this is to be able to program TelemetrEZ without having to open the case
or buy a 3rd party programmer... but really this now makes the SP board a
generic all-purpose programmer that can be used to program any AVR based
device with a standard 10-pin ISP header! The 9x's power status indicates
to the SP board whether it should be programming the 9x (9x is on) or the
target attached to the aux ISP line (9x is off).