Categories

Drops N’ Roses : External storage

Hey !

I am not really talkative since Friday. I am a little bit ill, and I think it explains why I am not so efficient.
Saturday, I was reading the datasheet of the FM25V20 FRAM memory. This memory was used last year by another group working on wireless dead drops for the storage of messages. I was going to implement the functions I need to use this memory with a SPI when Hubert came and said that I could not make any connection with our drops. As it was quite weird, I was concerned, and tried to connect to my own drop with gatttool. But it was not working : it returned an error for “connection denied”.
I tried to use previous commit whose state was steady. But it was all the same. I tried to flash the BLE stack again, to flash our program again. But there was nothing I can do to connect to mu drop : it was advertising, but that was all. At 7 pm, Lau came with her smartphone, and could make a connection between her phone and my device. It was kind of magic. I was not understand what was happening, and I was to tired to try anything else.

On Sunday, the first thing I did was trying to establish a connection with my drop thanks to gatttool. And it was working. I was really astonished. But I had to keep doing, so… I spend the afternoon and Monday morning to make a program using the SPI and allowing messages to be written in the FRAM.
When I tested it, and it was not working, I ask Alexis to lend me an analyzer in order to monitor which informations was really send.

The analyzer was really helpful, even if I had to weld again some wires in order to use it. Thanks to that, I saw that I was sending the data, but did not receive them when I tried to read them. Then… I figured out that it was because before each writting, I had to enable writting an data in the memory. So I fixed the issue. Then, I adjusted the code for BLE transmission. And I was done with the external storage.

When we would have our Flash memory, I think I would have to rewrite some functions (such as the method spi_master_tx_rx written by Nordic : it is really useful, but I think we can improve its behaviour for our needs).

PS : This morning, I helped RoseOnRails to weld some leds and rebuild their train circuit. They have a huge amount of welding to do.

Commentaires fermés.