Giga R1 SDRAM pin NC/A12

Official Hardware Mega GIGA R1 WiFi
1

The SDRAM U3 chip has an NC/A12 pin, that connects to the microcontroller's PG2 port (see below). The SDRAM datasheet says that nothing can be connected to the NC pin (see below below). Is there an error? The programmer can (accidentally or intentionally) set log.0 or log.1 on the PG2 line and disrupt SDRAM operation.

Giga_SDRAM
Giga_SDRAM318×566 54.5 KB

Giga_SDRAM2
Giga_SDRAM2869×239 41.9 KB

2

Hello!
Nothing changes since PG2 is not used in the code. The advantage is that it is a provision for a larger RAM without changing the PCB.

3

Thanks for the answer. But I meant the case when the programmer manually sets log.1 or log.0 on the PG2 output in his program. This will differ from the SDRAM datasheet recommendations. Have you tested this situation? Or does the programmer not have access to the PG2 pin?