The Sensor Network Museumtm - TinyNode 584 Knowledge Base
Known Hardware Errata
Some batches of TinyNodes have been shipped with "bad" RTC crystals. Measurements in the lab using a scope showed a deviation on the XOUT pin on the order of 32.4 kHz to 33.xx for what should actually be a rather stable 32.768 kHz. The good crystal oscillators show a behavior of around 32.768-32.769 kHz and have an engraved part number, whereas bad ones have printed markings.
|good quartz with nominal frequency||bad quartz with high deviation|
The Tinynode clocks are specified in the datasheet to a minumim of:
- RTC: Temperature coefficient of -0.034 ppm/C, Tolerance +25C of 20 ppm
- XE1205 Radio Clock (39MHz): Stability over Range -40 to +85C of 20 ppm, Tolerance +25C of 15 ppm
Shochfish Extension Board
The current version of the MamaBoard (v10), has a design issue that can potentially cause a bad communication between the TinyNode and the GPRS or the Ethernet module. It may or may not be apparent when powering the MamaBoard at 5V, but it will be when powering it at 6V or above. The symptom is that serial packets sent to the GPRS module can get lost or garbled. The fix involves adding a general purpose diode across the capacitor C19. Extension Boards are not affected.