On MRF89XA manual (https://www.olimex.com/Products/Modules/RF/MOD-MRF89-868/resources/MRF89XA.pdf#page=56) it says that in order to do a manual reset TEST8 pin must de driven high and then put it high-z state.
At the MRF89XAM9A manual (http://ww1.microchip.com/downloads/en/DeviceDoc/75017B.pdf#page=10) it shows that TEST8 is connected to RESET pin, but MOD-MRF89 (https://www.olimex.com/Products/Modules/RF/MOD-MRF89-868/resources/MOD-MRF89-868_sch.pdf) RESET pin looks like it must be constantly high/low (depending on the RESET value in the uext connector), never in high-z.
Is it possible to perform a RESET using this board?
The reset is available at pin #3 of the UEXT connector. If you want to reset the module set pin #3 at high level (3.3V) for ~100ms. If you wish to keep normal operation either keep it disconnected or set it at low level (0V).
Refer to "2.2 Reset Pin" from the datasheet of the 32-pin chip (the heart of the module manufactured by Microchip): http://ww1.microchip.com/downloads/en/DeviceDoc/70622C.pdf
By default we have used an RC (R1, C3) group that would accomplish the mentioned behavior from the datasheet automatically on power up. Initially, the reset would be high, once the capacitor gets charged the reset would be low.
Best regards,
Lub/OLIMEX