diff options
Diffstat (limited to 'src/jtag/ft2232.c')
| -rw-r--r-- | src/jtag/ft2232.c | 27 |
1 files changed, 9 insertions, 18 deletions
diff --git a/src/jtag/ft2232.c b/src/jtag/ft2232.c index c6125025..e63b2939 100644 --- a/src/jtag/ft2232.c +++ b/src/jtag/ft2232.c @@ -1415,22 +1415,9 @@ int ft2232_execute_queue() break; case JTAG_STABLECLOCKS: - /* "if (tap_move_map[cur_state] != -1)" is of no help when cur_state==TAP_IDLE */ - switch(cur_state) - { - case TAP_DRSHIFT: - case TAP_IDLE: - case TAP_RESET: - case TAP_DRPAUSE: - case TAP_IRSHIFT: - case TAP_IRPAUSE: - break; /* above stable states are OK */ - default: - LOG_ERROR( "jtag_add_clocks() was called with TAP in non-stable state \"%s\"", - jtag_state_name(cur_state) ); - retval = ERROR_JTAG_QUEUE_FAILED; - } - + /* this is only allowed while in a stable state. A check for a stable + * state was done in jtag_add_clocks() + */ if (ft2232_stableclocks(cmd->cmd.stableclocks->num_cycles, cmd) != ERROR_OK) retval = ERROR_JTAG_QUEUE_FAILED; #ifdef _DEBUG_JTAG_IO_ @@ -2336,11 +2323,15 @@ static int ft2232_stableclocks(int num_cycles, jtag_command_t *cmd) { int retval = 0; + /* 7 bits of either ones or zeros. */ + u8 tms = (cur_state == TAP_RESET ? 0x7F : 0x00); + while (num_cycles > 0) { /* the command 0x4b, "Clock Data to TMS/CS Pin (no Read)" handles * at most 7 bits per invocation. Here we invoke it potentially * several times. + * see: http://www.ftdichip.com/Documents/AppNotes/AN2232C-01_MPSSE_Cmnd.pdf */ int bitcount_per_command = (num_cycles > 7) ? 7 : num_cycles; @@ -2358,8 +2349,8 @@ static int ft2232_stableclocks(int num_cycles, jtag_command_t *cmd) /* scan 7 bit */ BUFFER_ADD = bitcount_per_command - 1; - /* TMS data bits are all zeros to stay in the current stable state */ - BUFFER_ADD = 0x0; + /* TMS data bits are either all zeros or ones to stay in the current stable state */ + BUFFER_ADD = tms; require_send = 1; |