Some devices such as AVR will return 0xffffffff instead of the TDI

[openocd.git] / src / jtag / jtag.c

diff --git a/src/jtag/jtag.c b/src/jtag/jtag.c
index 408f88fa5c351642d8f59ef08faabd0583283404..59f1991630d453c6d72d02d4a5783c508131cc85 100644 (file)
--- a/src/jtag/jtag.c
+++ b/src/jtag/jtag.c
@@ -1531,7 +1531,9 @@ int jtag_examine_chain(void)
                        u32 part;
                        u32 version;
 
-                       if (idcode == 0x000000FF)
+                       /* some devices, such as AVR will output all 1's instead of TDI
+                       input value at end of chain. */
+                       if ((idcode == 0x000000FF)||(idcode == 0xFFFFFFFF))
                        {
                                int unexpected=0;
                                /* End of chain (invalid manufacturer ID)
@@ -1548,7 +1550,7 @@ int jtag_examine_chain(void)
                                for (bit_count += 32; bit_count < (JTAG_MAX_CHAIN_SIZE * 32) - 31;bit_count += 32)
                                {
                                        idcode = buf_get_u32(idcode_buffer, bit_count, 32);
-                                       if (unexpected||(idcode != 0x000000FF))
+                                       if (unexpected||((idcode != 0x000000FF)&&(idcode != 0xFFFFFFFF)))
                                        {
                                                LOG_WARNING("Unexpected idcode after end of chain! %d 0x%08x", bit_count, idcode);
                                                unexpected = 1;
@@ -3306,7 +3308,7 @@ tap_state_t jtag_debug_state_machine(const void *tms_buf, const void *tdi_buf,
 
        tap_state_t last_state;
 
-       // set startstate (and possibly last, if tap_bits == 0) 
+       // set startstate (and possibly last, if tap_bits == 0)
        last_state = next_state;
        DEBUG_JTAG_IO("TAP/SM: START state: %s", tap_state_name(next_state));