X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=blobdiff_plain;f=src%2Fjtag%2Fbitbang.c;h=e8d082a7aa0b3f4d2fdca2420e4e37336a29d777;hp=a4e415c2ec8cff69c5de240ddffe67575bb629d9;hb=526fe3d83e118d87af34353a7140c02f3f1a3c19;hpb=4411c2643e41d023a1909b1040361912422be6c0 diff --git a/src/jtag/bitbang.c b/src/jtag/bitbang.c index a4e415c2ec..e8d082a7aa 100644 --- a/src/jtag/bitbang.c +++ b/src/jtag/bitbang.c @@ -2,6 +2,9 @@ * Copyright (C) 2005 by Dominic Rath * * Dominic.Rath@gmx.de * * * + * Copyright (C) 2007,2008 Øyvind Harboe * + * oyvind.harboe@zylin.com * + * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 2 of the License, or * @@ -34,16 +37,33 @@ #include #include -#include -#include - bitbang_interface_t *bitbang_interface; + +/* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work! + * + * Set this to 1 and str912 reset halt will fail. + * + * If someone can submit a patch with an explanation it will be greatly + * appreciated, but as far as I can tell (ØH) DCLK is generated upon + * clk=0 in TAP_RTI. Good luck deducing that from the ARM documentation! + * The ARM documentation uses the term "DCLK is asserted while in the TAP_RTI + * state". With hardware there is no such thing as *while* in a state. There + * are only edges. So clk => 0 is in fact a very subtle state transition that + * happens *while* in the TAP_RTI state. "#&¤"#¤&"#&"#& + * + * For "reset halt" the last thing that happens before srst is asserted + * is that the breakpoint is set up. If DCLK is not wiggled one last + * time before the reset, then the breakpoint is not set up and + * "reset halt" will fail to halt. + * + */ +#define CLOCK_IDLE() 0 + int bitbang_execute_queue(void); /* The bitbang driver leaves the TCK 0 when in idle */ - void bitbang_end_state(enum tap_state state) { if (tap_move_map[state] != -1) @@ -66,7 +86,7 @@ void bitbang_state_move(void) { bitbang_interface->write(0, tms, 0); bitbang_interface->write(1, tms, 0); } - bitbang_interface->write(0, tms, 0); + bitbang_interface->write(CLOCK_IDLE(), tms, 0); cur_state = end_state; } @@ -102,7 +122,7 @@ void bitbang_path_move(pathmove_command_t *cmd) num_states--; } - bitbang_interface->write(0, tms, 0); + bitbang_interface->write(CLOCK_IDLE(), tms, 0); end_state = cur_state; } @@ -121,12 +141,12 @@ void bitbang_runtest(int num_cycles) } /* execute num_cycles */ - bitbang_interface->write(0, 0, 0); for (i = 0; i < num_cycles; i++) { - bitbang_interface->write(1, 0, 0); bitbang_interface->write(0, 0, 0); + bitbang_interface->write(1, 0, 0); } + bitbang_interface->write(CLOCK_IDLE(), 0, 0); /* finish in end_state */ bitbang_end_state(saved_end_state); @@ -191,7 +211,7 @@ void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size) */ bitbang_interface->write(0, 0, 0); bitbang_interface->write(1, 0, 0); - bitbang_interface->write(0, 0, 0); + bitbang_interface->write(CLOCK_IDLE(), 0, 0); if (ir_scan) cur_state = TAP_PI; @@ -239,7 +259,7 @@ int bitbang_execute_queue(void) #ifdef _DEBUG_JTAG_IO_ LOG_DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst); #endif - if (cmd->cmd.reset->trst == 1) + if ((cmd->cmd.reset->trst == 1) || (cmd->cmd.reset->srst && (jtag_reset_config & RESET_SRST_PULLS_TRST))) { cur_state = TAP_TLR; }