doc/manual/jtag/drivers/remote_bitbang.txt

   1 /** @remote_bitbangpage OpenOCD Developer's Guide
   2
   3 The remote_bitbang JTAG driver is used to drive JTAG from a remote process. The
   4 remote_bitbang driver communicates via TCP or UNIX sockets with some remote
   5 process using an ASCII encoding of the bitbang interface. The remote process
   6 presumably then drives the JTAG however it pleases. The remote process should
   7 act as a server, listening for connections from the openocd remote_bitbang
   8 driver.
   9
  10 The remote bitbang driver is useful for debugging software running on
  11 processors which are being simulated.
  12
  13 The bitbang interface consists of the following functions.
  14
  15 blink on
  16         Blink a light somewhere. The argument on is either 1 or 0.
  17
  18 read
  19         Sample the value of tdo.
  20
  21 write tck tms tdi
  22         Set the value of tck, tms, and tdi.
  23
  24 reset trst srst
  25         Set the value of trst, srst.
  26
  27 An additional function, quit, is added to the remote_bitbang interface to
  28 indicate there will be no more requests and the connection with the remote
  29 driver should be closed.
  30
  31 These five functions are encoded in ascii by assigning a single character to
  32 each possible request. The assignments are:
  33
  34         B - Blink on
  35         b - Blink off
  36         R - Read request
  37         Q - Quit request
  38         0 - Write 0 0 0
  39         1 - Write 0 0 1
  40         2 - Write 0 1 0
  41         3 - Write 0 1 1
  42         4 - Write 1 0 0
  43         5 - Write 1 0 1
  44         6 - Write 1 1 0
  45         7 - Write 1 1 1
  46         r - Reset 0 0
  47         s - Reset 0 1
  48         t - Reset 1 0
  49         u - Reset 1 1
  50
  51 The read response is encoded in ascii as either digit 0 or 1.
  52
  53  */