On ARM official website, I saw some description about debug method by Freescale Vybrid.
It sounds like below (No JTAG or SW connection):
[PC Host] <--- USB wire ---> [Freescale Vybrid]
So it seems there is a bridge inside Vybrid, which is between USB module and DAP.
Inside Vybrid:
[USB I/O] <---> [USB module] <---> [Bridge] <---> [DAP]
Does ARM have such kind of bridge converting USB transaction to JTAG/SW DAP transaction ?
Hi,
Nowadays, a lot of boards use CMSIS-DAP to enable debug over USB. Basically, the debug circuitry is built into the design of the board so that you don't need a JTAG or SW connection. The debuggers in Keil MDK-ARM and ARM DS-5 Development Studio make it really easy to debug from your PC over USB.
Here's a tutorial on how it works with Vybrid and DS-5 Development studio: Developer Resources / Tutorials / Vybrid Tower System Debug Session Tutorial | ARM Development Studio 5
If you're building your own board, then here's the source code for implementing your own CMSIS-DAP interface firmware: mbedmicro/CMSIS-DAP · GitHub
Hope that helps,
Joe