I think 2N3055 is right, we should at least try to give good advice to the OP. Going back over this thread, it strikes me that there are 2 main groups of users of logic analyzers, basic and advanced which I will define as:
Basic. Examine simple data transfer to/from a device in one of many different protocols. e.g. 'talk' to a SPI device such as a temperature sensor to understand the way it works and maybe work up a simple driver.
Advanced. Study large amounts of data flowing between 2 or more devices on a bus on an existing PCB to understand and maybe debug issues that are suspected as being caused by signal levels, timing, or actual data transfer between the devices.
I tend to work at the basic level and have a need to be able to send as well as receive protocol data and, because of this, I find that I really don't use my real Saleae Logic 8 USB Logic Analyzer (PM me if you want to save me the trouble of listing it on eBay). I do own the Bus Pirate but, as I said before, it's UI is pretty crude and the firmware is a bit buggy - there is a
great overview of the Bus Pirate and how to use it here. What it will do - that the Saleae Logic 8 USB Logic Analyzer won't - is talk on the SPI/I2C/1Wire bus to discover and test new devices. It seems to me that this is the level that the OP is working at.
As far as Advanced goes, I really think sophisticated triggering is important so I can find the small amount of data I want to examine in detail rather than having to scroll through megabytes of stuff I don't care about; triggering is an area that the Saleae has been criticized for, don't know whether it's been improved? Having said that, the Saleae interface is very slick and intuitive.
As I look around for something more affordable than the Saleae, the DSLogic Plus with Sigrok looks like great bang for the buck but here's a few questions:
1. What's the difference between the $80ish DSlogic Plus and the
$300 DSLogic U3Pro16 on Seeed Studio? The ones I see on eBay when I search for "dslogic plus" are 16 Channel, 50 Meg ones that look identical and have what appears to be the same USB Type C connector as the U3Pro16 that is stated as running in USB 3.0 mode.
2. If I were to buy a DSlogic Plus from eBay for around $80, can anyone recommend a specific seller?
3. Is there any hardware supported by Sigrok that can write as well as read data to the connected bus?
Thanks in advance
[EDIT] There's also a Bus Pirate Console
here.