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Diffstat (limited to 'doc/manual/jtag/drivers/remote_bitbang.txt')
| -rw-r--r-- | doc/manual/jtag/drivers/remote_bitbang.txt | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/doc/manual/jtag/drivers/remote_bitbang.txt b/doc/manual/jtag/drivers/remote_bitbang.txt new file mode 100644 index 00000000..5a800479 --- /dev/null +++ b/doc/manual/jtag/drivers/remote_bitbang.txt @@ -0,0 +1,53 @@ +/** @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 driver is useful for debugging software running on +processors which are being simulated. + +The bitbang interface consists of the following functions. + +blink on + Blink a light somewhere. The argument on is either 1 or 0. + +read + Sample the value of tdo. + +write tck tms tdi + Set the value of tck, tms, and tdi. + +reset trst srst + Set the value of trst, srst. + +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 +each possible request. The assignments are: + + B - Blink on + b - Blink off + R - Read request + Q - Quit request + 0 - Write 0 0 0 + 1 - Write 0 0 1 + 2 - Write 0 1 0 + 3 - Write 0 1 1 + 4 - Write 1 0 0 + 5 - Write 1 0 1 + 6 - Write 1 1 0 + 7 - Write 1 1 1 + r - Reset 0 0 + s - Reset 0 1 + t - Reset 1 0 + u - Reset 1 1 + +The read response is encoded in ascii as either digit 0 or 1. + + */ |