External SPI-SRAM Add-on Board for NPR-70 v04 | New Packet Radio over 70cm Band | Amateur Radio Packet Radio

This is a SPI-SRAM add-on board for NPR-70 v04 modems. This add-on board will greatly improve the performance of NPR-70 v04 modem while it is in transmitting, especially for the Master modems. The upgrade process is really simple, just put it on top of mcu board, and solder the 7 marked pins. The new firmware (2020_02_23) will automatically detect the board and make use of it. In order to determine if you need this upgrade, refer to the “advanced user guide”.

Notes:

• 1. This add-on board is only for NPR-70 v04 modem, not for v05, v03, v02 ones.
• 2. You have to upgrade the firmware to the new version “2020_02_23”, please go to NPR-70 modem’s hackaday page for downloading, https://hackaday.io/project/16409
• 3. In order to check that the SPI-SRAM board is well assembled and detected, trigger a “display config” command in terminal, and check that the answer contains “ext_SRAM: yes”.