Hi Jack,
Iâm the developer of the PortaPack. Iâm not clear about what you want to do, but I can try to answer your questions.
If youâre interested in the RSSI signal, itâs generated by the MAX2837, the chip that performs the second IF function. Itâs hooked up to an analog to digital converter on the LPC4320 microcontroller. So with a few changes to the firmware, you can read it out via USB. Or you can use the RSSI value from within your own HackRF firmware, if you canât afford the latency that USB would add.
The PortaPack is programmed using a subset of C++11. The firmware is open-source (GPL) and available on GitHub, if you want to look it over and appropriate parts for your own use:
https://github.com/sharebrained/portapack-hackrf/
Thereâs also the HAVOC fork of the project firmware which is definitely worth looking at.
The PortaPack uses the ELM-ChaN FatFs project to write FAT32 SD cards:
http://elm-chan.org/fsw/ff/00index_e.html
There is an option in the project to enable ExFAT, but I donât do that because of patents. Iâve tested write performance of about 7 Mbytes/sec on high-quality SD cards. However most SD cards have an annoying habit of periodically âdigestingâ written data for tens of milliseconds. So sustained writes with the small amount of buffer RAM available on the microcontroller limits sustained write speeds to approximately 2 Mbytes/sec.
I hope that helps.
- Jared
Post by Jack HuntHello!
I have some questions in regards to the Portapack. I'm looking to create a similar board, without a screen and button, that can pass the RSSI through. I was wondering how the Portapack's firmware was programmed (what software was used). Also how the data that is stored on the SD card is formatted.
Thanks,
Jack
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