Add CMD_START_FLAGS_CLK_CTL2 command flag

This command will generate a suitable clock on pin CTL2 for
devices with an analog input.

diff --git a/gpif-acquisition.c b/gpif-acquisition.c
index 039f81408cd6268384221faa7757fa60edbd9070..b05f4f3cd7b39a4500bc7ee23f7b970e45e4f705 100644 (file)
--- a/gpif-acquisition.c
+++ b/gpif-acquisition.c
@@ -213,16 +213,32 @@ bool gpif_acquisition_start(const struct cmd_start_acquisition *cmd)
                           bmGSTATE | bmIFGPIF;
        }
 
-       /* Populate delay states. */
-       if ((cmd->sample_delay_h == 0 && cmd->sample_delay_l == 0) ||
-           cmd->sample_delay_h >= 6)
-               return false;
+       if (cmd->flags & CMD_START_FLAGS_CLK_CTL2) {
+               uint8_t delay_1, delay_2;
 
-       for (i = 0; i < cmd->sample_delay_h; i++)
-               gpif_make_delay_state(pSTATE++, 0, 0x00, 0x00);
+               /* We need a pulse where the CTL2 pin alternates states. */
 
-       if (cmd->sample_delay_l != 0)
-               gpif_make_delay_state(pSTATE++, cmd->sample_delay_l, 0x00, 0x00);
+               /* Make the low pulse shorter then the high pulse. */
+               delay_2 = cmd->sample_delay_l >> 2;
+               /* Work around >12MHz case resulting in a 0 delay low pulse. */
+               if (delay_2 == 0)
+                       delay_2 = 1;
+               delay_1 = cmd->sample_delay_l - delay_2;
+
+               gpif_make_delay_state(pSTATE++, delay_2, 0x00, 0x40);
+               gpif_make_delay_state(pSTATE++, delay_1, 0x00, 0x44);
+       } else {
+               /* Populate delay states. */
+               if ((cmd->sample_delay_h == 0 && cmd->sample_delay_l == 0) ||
+                       cmd->sample_delay_h >= 6)
+                       return false;
+
+               for (i = 0; i < cmd->sample_delay_h; i++)
+                       gpif_make_delay_state(pSTATE++, 0, 0x00, 0x00);
+
+               if (cmd->sample_delay_l != 0)
+                       gpif_make_delay_state(pSTATE++, cmd->sample_delay_l, 0x00, 0x00);
+       }
 
        /* Populate S1 - the decision point. */
        gpid_make_data_dp_state(pSTATE++);

diff --git a/include/command.h b/include/command.h
index 59a9f902cfc6c2cd6192c6a7f00245ab5c6c4266..c965720e444396cafa8f0af34aef0965c07d13ce 100644 (file)
--- a/include/command.h
+++ b/include/command.h
@@ -28,9 +28,11 @@
 #define CMD_START                      0xb1
 #define CMD_GET_REVID_VERSION          0xb2
 
+#define CMD_START_FLAGS_CLK_CTL2_POS   4
 #define CMD_START_FLAGS_WIDE_POS       5
 #define CMD_START_FLAGS_CLK_SRC_POS    6
 
+#define CMD_START_FLAGS_CLK_CTL2       (1 << CMD_START_FLAGS_CLK_CTL2_POS)
 #define CMD_START_FLAGS_SAMPLE_8BIT    (0 << CMD_START_FLAGS_WIDE_POS)
 #define CMD_START_FLAGS_SAMPLE_16BIT   (1 << CMD_START_FLAGS_WIDE_POS)