Suunto Gecko - Year and Nitrox bug?

[Jef Driesen]

On 2012-03-28 22:42, Björn Spruck wrote:
> PS: why does it take minutes to transfer 8kb of data? At 9600baud 
> this
> should be order 10seconds?

The baudrate is only one part of the story, and for the vyper protocol 
the slow baudrate is in fact the least important one.

When sending a request to the device, the protocol requires to wait 
some time (500ms) before sending the command, and again some time before 
reading the response (200ms). Since the 8K is send in packets of 32 
bytes, that means those 256 packets require already 3 mins of waiting. 
In addition, you also have to take into account that the device doesn't 
respond immediately and the time to read a 32 byte packet is much larger 
(typically 300 to 500ms) compared to the theoretical transmission time.

Thus it's not the slow baudrate that makes the downloading slow. 
Luckily downloading dives is a little faster than doing a full dump, 
because the protocol requires only a single request for each not dive.

Jef