diff options
Diffstat (limited to 'doc/manual/jtag/drivers/remote_bitbang.txt')
| -rw-r--r-- | doc/manual/jtag/drivers/remote_bitbang.txt | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/doc/manual/jtag/drivers/remote_bitbang.txt b/doc/manual/jtag/drivers/remote_bitbang.txt index f394d73..7c8eee2 100644 --- a/doc/manual/jtag/drivers/remote_bitbang.txt +++ b/doc/manual/jtag/drivers/remote_bitbang.txt @@ -1,15 +1,19 @@ /** @remote_bitbangpage OpenOCD Developer's Guide -The remote_bitbang JTAG driver is used to drive JTAG from a remote process. The -remote_bitbang driver communicates via TCP or UNIX sockets with some remote -process using an ASCII encoding of the bitbang interface. The remote process -presumably then drives the JTAG however it pleases. The remote process should -act as a server, listening for connections from the openocd remote_bitbang -driver. +The remote_bitbang JTAG+SWD driver is used to drive JTAG and/or SWD from a +remote process. The remote_bitbang driver communicates via TCP or UNIX +sockets with some remote process using an ASCII encoding of the bitbang +interface. The remote process presumably then drives the JTAG/SWD however +it pleases. The remote process should act as a server, listening for +connections from the openocd remote_bitbang driver. The remote bitbang driver is useful for debugging software running on processors which are being simulated. +There also is an implementation of the server-side protocol for the +Glasgow Debug Tool (https://github.com/glasgowEmbedded/Glasgow) through +the jtag-openocd applet. + The bitbang interface consists of the following functions. blink on @@ -24,11 +28,20 @@ write tck tms tdi reset trst srst Set the value of trst, srst. +swdio_drive + Set the output enable of the bidirectional swdio (tms) pin + +swdio_read + Sample the value of swdio (tms). + +swd_write + Set the value of swclk (tck) and swdio (tms). + An additional function, quit, is added to the remote_bitbang interface to indicate there will be no more requests and the connection with the remote driver should be closed. -These five functions are encoded in ASCII by assigning a single character to +These eight functions are encoded in ASCII by assigning a single character to each possible request. The assignments are: B - Blink on @@ -47,7 +60,14 @@ each possible request. The assignments are: s - Reset 0 1 t - Reset 1 0 u - Reset 1 1 + O - SWDIO drive 1 + o - SWDIO drive 0 + c - SWDIO read request + d - SWD write 0 0 + e - SWD write 0 1 + f - SWD write 1 0 + g - SWD write 1 1 -The read response is encoded in ASCII as either digit 0 or 1. +The read responses are encoded in ASCII as either digit 0 or 1. */ |