Pavel Chromy: TCK returns to zero before state of reset line is changed.

git-svn-id: svn://svn.berlios.de/openocd/trunk@703 b42882b7-edfa-0310-969c-e2dbd0fdcd60

diff --git a/src/jtag/presto.c b/src/jtag/presto.c
index c031d94b1dac8f30b8d7f9811e7019f6c28ab7a1..3fd0ee1219f1069fc9d6c7cf38270ee8d92aca76 100644 (file)
--- a/src/jtag/presto.c
+++ b/src/jtag/presto.c
@@ -573,10 +573,10 @@ int presto_bitq_out(int tms, int tdi, int tdo_req)
 
        if (presto->jtag_tck == 0)
        {
-               presto_sendbyte(0xA4);
-               presto->jtag_tck = 1;
+               presto_sendbyte(0xA4); /* jtag activity */
+               presto->jtag_tck = 1; /* clock remains high after the function returns */
+               /* do just a single tick first, accelerated shifting needs TCK=1 */
        }
-
        else if (!tdo_req && tms == presto->jtag_tms)
        {
                if (presto->jtag_tdi_count == 0)
@@ -617,7 +617,7 @@ int presto_bitq_out(int tms, int tdi, int tdo_req)
        }
 
        if (tdo_req)
-               presto_sendbyte(0xD4 | cmdparam);
+               presto_sendbyte(0xD4|cmdparam);
        else
                presto_sendbyte(0xC4|cmdparam);
 
@@ -634,8 +634,11 @@ int presto_bitq_flush(void)
                presto->jtag_tdi_count = 0;
        }
 
-       presto_sendbyte(0xCA);
-       presto->jtag_tck = 0;
+       if (presto->jtag_tck == 1) 
+       {
+               presto_sendbyte(0xCA);
+               presto->jtag_tck = 0;
+       }
 
        presto_sendbyte(0xA0);
 
@@ -664,6 +667,12 @@ int presto_bitq_sleep(unsigned long us)
 {
        long waits;
 
+       if (presto->jtag_tck == 1) 
+       {
+               presto_sendbyte(0xCA);
+               presto->jtag_tck = 0;
+       }
+
        if (us > 100000)
        {
                presto_bitq_flush();
@@ -683,6 +692,12 @@ int presto_bitq_reset(int trst, int srst)
 {
        unsigned char cmd;
 
+       if (presto->jtag_tck == 1) 
+       {
+               presto_sendbyte(0xCA);
+               presto->jtag_tck = 0;
+       }
+
        cmd = 0xE8;
        if (presto->jtag_tms)
                cmd |= 0x04;