diff --git a/artiq/coredevice/dds.py b/artiq/coredevice/dds.py
index 7799c1d31..8ab434664 100644
--- a/artiq/coredevice/dds.py
+++ b/artiq/coredevice/dds.py
@@ -79,7 +79,9 @@ class DDS(AutoDB):
 
     @kernel
     def init(self):
-        """Resets and initializes the DDS channel."""
+        """Resets and initializes the DDS channel.
+
+        The runtime does this for all channels upon core device startup."""
         syscall("dds_init", time_to_cycles(now()), self.channel)
 
     @kernel
diff --git a/soc/runtime/Makefile b/soc/runtime/Makefile
index 1d93d6e63..3cf2708dc 100644
--- a/soc/runtime/Makefile
+++ b/soc/runtime/Makefile
@@ -1,6 +1,6 @@
 include $(MSCDIR)/software/common.mak
 
-OBJECTS := isr.o flash_storage.o clock.o elf_loader.o services.o session.o log.o test_mode.o kloader.o mailbox.o ksupport_data.o kserver.o main.o
+OBJECTS := isr.o flash_storage.o clock.o elf_loader.o services.o session.o log.o test_mode.o kloader.o bridge_ctl.o mailbox.o ksupport_data.o kserver.o main.o
 OBJECTS_KSUPPORT := ksupport.o exception_jmp.o exceptions.o mailbox.o bridge.o rtio.o ttl.o dds.o
 
 CFLAGS += -Ilwip/src/include -Iliblwip
diff --git a/soc/runtime/bridge.c b/soc/runtime/bridge.c
index 19cfd4b4e..c61875236 100644
--- a/soc/runtime/bridge.c
+++ b/soc/runtime/bridge.c
@@ -58,6 +58,10 @@ void bridge_main(void)
                 mailbox_acknowledge();
                 break;
             }
+            case MESSAGE_TYPE_BRG_DDS_INITALL:
+                dds_init_all();
+                mailbox_acknowledge();
+                break;
             case MESSAGE_TYPE_BRG_DDS_SEL: {
                 struct msg_brg_dds_sel *msg;
 
diff --git a/soc/runtime/bridge_ctl.c b/soc/runtime/bridge_ctl.c
new file mode 100644
index 000000000..1103a222c
--- /dev/null
+++ b/soc/runtime/bridge_ctl.c
@@ -0,0 +1,113 @@
+#include <stdio.h>
+
+#include "kloader.h"
+#include "mailbox.h"
+#include "messages.h"
+
+void brg_start(void)
+{
+    struct msg_base *umsg;
+
+    kloader_start_bridge();
+
+    while(1) {
+        umsg = mailbox_wait_and_receive();
+        if(umsg->type == MESSAGE_TYPE_BRG_READY) {
+            mailbox_acknowledge();
+            break;
+        } else {
+            printf("Warning: unexpected message %d from AMP bridge\n", umsg->type);
+            mailbox_acknowledge();
+        }
+    }
+}
+
+void brg_stop(void)
+{
+    kloader_stop();
+}
+
+void brg_ttloe(int n, int value)
+{
+    struct msg_brg_ttl_out msg;
+
+    msg.type = MESSAGE_TYPE_BRG_TTL_OE;
+    msg.channel = n;
+    msg.value = value;
+    mailbox_send_and_wait(&msg);
+}
+
+void brg_ttlo(int n, int value)
+{
+    struct msg_brg_ttl_out msg;
+
+    msg.type = MESSAGE_TYPE_BRG_TTL_O;
+    msg.channel = n;
+    msg.value = value;
+    mailbox_send_and_wait(&msg);
+}
+
+void brg_ddsinitall(void)
+{
+    struct msg_base msg;
+
+    msg.type = MESSAGE_TYPE_BRG_DDS_INITALL;
+    mailbox_send_and_wait(&msg);
+}
+
+void brg_ddssel(int channel)
+{
+    struct msg_brg_dds_sel msg;
+
+    msg.type = MESSAGE_TYPE_BRG_DDS_SEL;
+    msg.channel = channel;
+    mailbox_send_and_wait(&msg);
+}
+
+void brg_ddsreset(void)
+{
+    struct msg_base msg;
+
+    msg.type = MESSAGE_TYPE_BRG_DDS_RESET;
+    mailbox_send_and_wait(&msg);
+}
+
+unsigned int brg_ddsread(unsigned int address)
+{
+    struct msg_brg_dds_read_request msg;
+    struct msg_brg_dds_read_reply *rmsg;
+    unsigned int r;
+
+    msg.type = MESSAGE_TYPE_BRG_DDS_READ_REQUEST;
+    msg.address = address;
+    mailbox_send(&msg);
+    while(1) {
+        rmsg = mailbox_wait_and_receive();
+        if(rmsg->type == MESSAGE_TYPE_BRG_DDS_READ_REPLY) {
+            r = rmsg->data;
+            mailbox_acknowledge();
+            return r;
+        } else {
+            printf("Warning: unexpected message %d from AMP bridge\n", rmsg->type);
+            mailbox_acknowledge();
+        }
+    }
+}
+
+void brg_ddswrite(unsigned int address, unsigned int data)
+{
+    struct msg_brg_dds_write msg;
+
+    msg.type = MESSAGE_TYPE_BRG_DDS_WRITE;
+    msg.address = address;
+    msg.data = data;
+    mailbox_send_and_wait(&msg);
+}
+
+void brg_ddsfud(void)
+{
+    struct msg_base msg;
+
+    msg.type = MESSAGE_TYPE_BRG_DDS_FUD;
+    mailbox_send_and_wait(&msg);
+}
diff --git a/soc/runtime/bridge_ctl.h b/soc/runtime/bridge_ctl.h
new file mode 100644
index 000000000..d87f83812
--- /dev/null
+++ b/soc/runtime/bridge_ctl.h
@@ -0,0 +1,17 @@
+#ifndef __BRIDGE_CTL_H
+#define __BRIDGE_CTL_H
+
+void brg_start(void);
+void brg_stop(void);
+
+void brg_ttloe(int n, int value);
+void brg_ttlo(int n, int value);
+
+void brg_ddsinitall(void);
+void brg_ddssel(int channel);
+void brg_ddsreset(void);
+unsigned int brg_ddsread(unsigned int address);
+void brg_ddswrite(unsigned int address, unsigned int data);
+void brg_ddsfud(void);
+
+#endif /* __BRIDGE_CTL_H */
diff --git a/soc/runtime/dds.c b/soc/runtime/dds.c
index ea8a44a90..2429eb2b6 100644
--- a/soc/runtime/dds.c
+++ b/soc/runtime/dds.c
@@ -6,6 +6,7 @@
 #include "dds.h"
 
 #define DURATION_WRITE 5
+#define DURATION_INIT (8*DURATION_WRITE)
 #define DURATION_PROGRAM (8*DURATION_WRITE)
 
 #define DDS_WRITE(addr, data) do { \
@@ -16,13 +17,26 @@
         now += DURATION_WRITE; \
     } while(0)
 
+void dds_init_all(void)
+{
+    int i;
+    long long int now;
+
+    now = rtio_get_counter() + 10000;
+    for(i=0;i<DDS_CHANNEL_COUNT;i++) {
+        dds_init(now, i);
+        now += DURATION_INIT;
+    }
+    while(rtio_get_counter() < now);
+}
+
 void dds_init(long long int timestamp, int channel)
 {
     long long int now;
 
     rtio_chan_sel_write(RTIO_DDS_CHANNEL);
 
-    now = timestamp - 7*DURATION_WRITE;
+    now = timestamp - DURATION_INIT;
 
     DDS_WRITE(DDS_GPIO, channel);
     DDS_WRITE(DDS_GPIO, channel | (1 << 7));
@@ -32,6 +46,8 @@ void dds_init(long long int timestamp, int channel)
     DDS_WRITE(0x01, 0x00);
     DDS_WRITE(0x02, 0x00);
     DDS_WRITE(0x03, 0x00);
+
+    DDS_WRITE(DDS_FUD, 0);
 }
 
 static void dds_set_one(long long int now, long long int timestamp, int channel,
diff --git a/soc/runtime/dds.h b/soc/runtime/dds.h
index f0f551a5c..e6adc326c 100644
--- a/soc/runtime/dds.h
+++ b/soc/runtime/dds.h
@@ -4,6 +4,9 @@
 #include <hw/common.h>
 #include <generated/mem.h>
 
+/* Number of DDS channels to initialize */
+#define DDS_CHANNEL_COUNT 8
+
 /* Maximum number of commands in a batch */
 #define DDS_MAX_BATCH 16
 
@@ -23,6 +26,7 @@ enum {
     PHASE_MODE_TRACKING = 2
 };
 
+void dds_init_all(void);
 void dds_init(long long int timestamp, int channel);
 void dds_batch_enter(long long int timestamp);
 void dds_batch_exit(void);
diff --git a/soc/runtime/kloader.c b/soc/runtime/kloader.c
index 6cbea69d8..f73723981 100644
--- a/soc/runtime/kloader.c
+++ b/soc/runtime/kloader.c
@@ -117,7 +117,7 @@ void kloader_start_idle_kernel(void)
 #endif
 }
 
-void kloader_stop_kernel(void)
+void kloader_stop(void)
 {
     kernel_cpu_reset_write(1);
     mailbox_acknowledge();
diff --git a/soc/runtime/kloader.h b/soc/runtime/kloader.h
index 10993ca41..bf484b4e1 100644
--- a/soc/runtime/kloader.h
+++ b/soc/runtime/kloader.h
@@ -12,6 +12,6 @@ kernel_function kloader_find(const char *name);
 void kloader_start_bridge(void);
 void kloader_start_idle_kernel(void);
 void kloader_start_user_kernel(kernel_function k);
-void kloader_stop_kernel(void);
+void kloader_stop(void);
 
 #endif /* __KLOADER_H */
diff --git a/soc/runtime/main.c b/soc/runtime/main.c
index 5e2e547da..95889fd07 100644
--- a/soc/runtime/main.c
+++ b/soc/runtime/main.c
@@ -21,12 +21,22 @@
 #include <lwip/timers.h>
 #endif
 
+#include "bridge_ctl.h"
+#include "kloader.h"
 #include "flash_storage.h"
 #include "clock.h"
 #include "test_mode.h"
 #include "kserver.h"
 #include "session.h"
 
+static void common_init(void)
+{
+    clock_init();
+    brg_start();
+    brg_ddsinitall();
+    kloader_stop();
+}
+
 #ifdef CSR_ETHMAC_BASE
 
 u32_t sys_now(void)
@@ -127,7 +137,6 @@ static void network_init(void)
 static void regular_main(void)
 {
     puts("Accepting sessions on Ethernet.");
-    clock_init();
     network_init();
     kserver_init();
 
@@ -186,7 +195,6 @@ static void serial_service(void)
 static void regular_main(void)
 {
     puts("Accepting sessions on serial link.");
-    clock_init();
 
     /* Open the session for the serial control. */
     session_start();
@@ -246,6 +254,7 @@ int main(void)
         test_main();
     } else {
         puts("Entering regular mode.");
+        common_init();
         regular_main();
     }
     return 0;
diff --git a/soc/runtime/messages.h b/soc/runtime/messages.h
index 4a4e10737..221b394a3 100644
--- a/soc/runtime/messages.h
+++ b/soc/runtime/messages.h
@@ -19,6 +19,7 @@ enum {
     MESSAGE_TYPE_BRG_READY,
     MESSAGE_TYPE_BRG_TTL_O,
     MESSAGE_TYPE_BRG_TTL_OE,
+    MESSAGE_TYPE_BRG_DDS_INITALL,
     MESSAGE_TYPE_BRG_DDS_SEL,
     MESSAGE_TYPE_BRG_DDS_RESET,
     MESSAGE_TYPE_BRG_DDS_READ_REQUEST,
diff --git a/soc/runtime/session.c b/soc/runtime/session.c
index bfcc6b823..a0f2d3ab7 100644
--- a/soc/runtime/session.c
+++ b/soc/runtime/session.c
@@ -67,13 +67,13 @@ void session_start(void)
 {
     buffer_in_index = 0;
     memset(&buffer_out[4], 0, 4);
-    kloader_stop_kernel();
+    kloader_stop();
     user_kernel_state = USER_KERNEL_NONE;
 }
 
 void session_end(void)
 {
-    kloader_stop_kernel();
+    kloader_stop();
     kloader_start_idle_kernel();
 }
 
@@ -417,7 +417,7 @@ static int process_kmsg(struct msg_base *umsg)
             buffer_out[8] = REMOTEMSG_TYPE_KERNEL_FINISHED;
             submit_output(9);
 
-            kloader_stop_kernel();
+            kloader_stop();
             user_kernel_state = USER_KERNEL_LOADED;
             mailbox_acknowledge();
             break;
@@ -429,7 +429,7 @@ static int process_kmsg(struct msg_base *umsg)
             memcpy(&buffer_out[13], msg->eparams, 3*8);
             submit_output(9+4+3*8);
 
-            kloader_stop_kernel();
+            kloader_stop();
             user_kernel_state = USER_KERNEL_LOADED;
             mailbox_acknowledge();
             break;
diff --git a/soc/runtime/test_mode.c b/soc/runtime/test_mode.c
index 5b018c4d9..0b0ee6426 100644
--- a/soc/runtime/test_mode.c
+++ b/soc/runtime/test_mode.c
@@ -7,113 +7,11 @@
 #include <generated/csr.h>
 #include <console.h>
 
-#include "kloader.h"
-#include "mailbox.h"
-#include "messages.h"
 #include "dds.h"
 #include "flash_storage.h"
+#include "bridge_ctl.h"
 #include "test_mode.h"
 
-/* bridge access functions */
-
-static void amp_bridge_init(void)
-{
-    struct msg_base *umsg;
-
-    kloader_start_bridge();
-
-    while(1) {
-        umsg = mailbox_wait_and_receive();
-        if(umsg->type == MESSAGE_TYPE_BRG_READY) {
-            printf("AMP bridge ready\n");
-            mailbox_acknowledge();
-            break;
-        } else {
-            printf("Warning: unexpected message %d from AMP bridge\n", umsg->type);
-            mailbox_acknowledge();
-        }
-    }
-}
-
-static void p_ttloe(int n, int value)
-{
-    struct msg_brg_ttl_out msg;
-
-    msg.type = MESSAGE_TYPE_BRG_TTL_OE;
-    msg.channel = n;
-    msg.value = value;
-    mailbox_send_and_wait(&msg);
-}
-
-static void p_ttlo(int n, int value)
-{
-    struct msg_brg_ttl_out msg;
-
-    msg.type = MESSAGE_TYPE_BRG_TTL_O;
-    msg.channel = n;
-    msg.value = value;
-    mailbox_send_and_wait(&msg);
-}
-
-static void p_ddssel(int channel)
-{
-    struct msg_brg_dds_sel msg;
-
-    msg.type = MESSAGE_TYPE_BRG_DDS_SEL;
-    msg.channel = channel;
-    mailbox_send_and_wait(&msg);
-}
-
-static void p_ddsreset(void)
-{
-    struct msg_base msg;
-
-    msg.type = MESSAGE_TYPE_BRG_DDS_RESET;
-    mailbox_send_and_wait(&msg);
-}
-
-static unsigned int p_ddsread(unsigned int address)
-{
-    struct msg_brg_dds_read_request msg;
-    struct msg_brg_dds_read_reply *rmsg;
-    unsigned int r;
-
-    msg.type = MESSAGE_TYPE_BRG_DDS_READ_REQUEST;
-    msg.address = address;
-    mailbox_send(&msg);
-    while(1) {
-        rmsg = mailbox_wait_and_receive();
-        if(rmsg->type == MESSAGE_TYPE_BRG_DDS_READ_REPLY) {
-            r = rmsg->data;
-            mailbox_acknowledge();
-            return r;
-        } else {
-            printf("Warning: unexpected message %d from AMP bridge\n", rmsg->type);
-            mailbox_acknowledge();
-        }
-    }
-}
-
-static void p_ddswrite(unsigned int address, unsigned int data)
-{
-    struct msg_brg_dds_write msg;
-
-    msg.type = MESSAGE_TYPE_BRG_DDS_WRITE;
-    msg.address = address;
-    msg.data = data;
-    mailbox_send_and_wait(&msg);
-}
-
-static void p_ddsfud(void)
-{
-    struct msg_base msg;
-
-    msg.type = MESSAGE_TYPE_BRG_DDS_FUD;
-    mailbox_send_and_wait(&msg);
-}
-
-/* */
-
 static void leds(char *value)
 {
     char *c;
@@ -173,7 +71,7 @@ static void ttloe(char *n, char *value)
         return;
     }
 
-    p_ttloe(n2, value2);
+    brg_ttloe(n2, value2);
 }
 
 static void ttlo(char *n, char *value)
@@ -197,7 +95,7 @@ static void ttlo(char *n, char *value)
         return;
     }
 
-    p_ttlo(n2, value2);
+    brg_ttlo(n2, value2);
 }
 
 static void ddssel(char *n)
@@ -216,7 +114,7 @@ static void ddssel(char *n)
         return;
     }
 
-    p_ddssel(n2);
+    brg_ddssel(n2);
 }
 
 static void ddsw(char *addr, char *value)
@@ -240,7 +138,7 @@ static void ddsw(char *addr, char *value)
         return;
     }
 
-    p_ddswrite(addr2, value2);
+    brg_ddswrite(addr2, value2);
 }
 
 static void ddsr(char *addr)
@@ -259,12 +157,12 @@ static void ddsr(char *addr)
         return;
     }
 
-    printf("0x%02x\n", p_ddsread(addr2));
+    printf("0x%02x\n", brg_ddsread(addr2));
 }
 
 static void ddsfud(void)
 {
-    p_ddsfud();
+    brg_ddsfud();
 }
 
 static void ddsftw(char *n, char *ftw)
@@ -288,27 +186,27 @@ static void ddsftw(char *n, char *ftw)
         return;
     }
 
-    p_ddssel(n2);
-    p_ddswrite(DDS_FTW0, ftw2 & 0xff);
-    p_ddswrite(DDS_FTW1, (ftw2 >> 8) & 0xff);
-    p_ddswrite(DDS_FTW2, (ftw2 >> 16) & 0xff);
-    p_ddswrite(DDS_FTW3, (ftw2 >> 24) & 0xff);
-    p_ddsfud();
+    brg_ddssel(n2);
+    brg_ddswrite(DDS_FTW0, ftw2 & 0xff);
+    brg_ddswrite(DDS_FTW1, (ftw2 >> 8) & 0xff);
+    brg_ddswrite(DDS_FTW2, (ftw2 >> 16) & 0xff);
+    brg_ddswrite(DDS_FTW3, (ftw2 >> 24) & 0xff);
+    brg_ddsfud();
 }
 
 static void ddsreset(void)
 {
-    p_ddsreset();
+    brg_ddsreset();
 }
 
 static void ddsinit(void)
 {
-    p_ddsreset();
-    p_ddswrite(0x00, 0x78);
-    p_ddswrite(0x01, 0x00);
-    p_ddswrite(0x02, 0x00);
-    p_ddswrite(0x03, 0x00);
-    p_ddsfud();
+    brg_ddsreset();
+    brg_ddswrite(0x00, 0x78);
+    brg_ddswrite(0x01, 0x00);
+    brg_ddswrite(0x02, 0x00);
+    brg_ddswrite(0x03, 0x00);
+    brg_ddsfud();
 }
 
 static void ddstest_one(unsigned int i)
@@ -320,20 +218,20 @@ static void ddstest_one(unsigned int i)
     };
     unsigned int f, g, j;
 
-    p_ddssel(i);
+    brg_ddssel(i);
     ddsinit();
 
     for(j=0; j<12; j++) {
         f = v[j];
-        p_ddswrite(0x0a, f & 0xff);
-        p_ddswrite(0x0b, (f >> 8) & 0xff);
-        p_ddswrite(0x0c, (f >> 16) & 0xff);
-        p_ddswrite(0x0d, (f >> 24) & 0xff);
-        p_ddsfud();
-        g = p_ddsread(0x0a);
-        g |= p_ddsread(0x0b) << 8;
-        g |= p_ddsread(0x0c) << 16;
-        g |= p_ddsread(0x0d) << 24;
+        brg_ddswrite(0x0a, f & 0xff);
+        brg_ddswrite(0x0b, (f >> 8) & 0xff);
+        brg_ddswrite(0x0c, (f >> 16) & 0xff);
+        brg_ddswrite(0x0d, (f >> 24) & 0xff);
+        brg_ddsfud();
+        g = brg_ddsread(0x0a);
+        g |= brg_ddsread(0x0b) << 8;
+        g |= brg_ddsread(0x0c) << 16;
+        g |= brg_ddsread(0x0d) << 24;
         if(g != f)
             printf("readback fail on DDS %d, 0x%08x != 0x%08x\n", i, g, f);
     }
@@ -479,7 +377,7 @@ void test_main(void)
 {
     char buffer[64];
 
-    amp_bridge_init();
+    brg_start();
 
     while(1) {
         putsnonl("\e[1mtest>\e[0m ");