diff --git a/riscv.sc/incl/sysc/General/system.h b/riscv.sc/incl/sysc/General/system.h
new file mode 100644
index 0000000..9645762
--- /dev/null
+++ b/riscv.sc/incl/sysc/General/system.h
@@ -0,0 +1,30 @@
+/*
+ * system.h
+ *
+ *  Created on: 11.07.2018
+ *      Author: eyck
+ */
+
+#ifndef __SYSC_GENERAL_SYSTEM_H_
+#define __SYSC_GENERAL_SYSTEM_H_
+
+#include "sysc/SiFive/platform.h"
+#include "sysc/General/terminal.h"
+#include <systemc>
+
+namespace sysc {
+
+class system: sc_core::sc_module {
+public:
+    system(sc_core::sc_module_name nm);
+    virtual ~system();
+
+    sc_core::sc_vector<tlm::tlm_signal<sc_dt::sc_logic>> s_gpio;
+
+private:
+    sysc::platform i_platform;
+    sysc::terminal i_terminal;
+};
+
+}
+#endif /* __SYSC_GENERAL_SYSTEM_H_ */
diff --git a/riscv.sc/incl/sysc/General/terminal.h b/riscv.sc/incl/sysc/General/terminal.h
new file mode 100644
index 0000000..d614051
--- /dev/null
+++ b/riscv.sc/incl/sysc/General/terminal.h
@@ -0,0 +1,42 @@
+/*
+ * terminal.h
+ *
+ *  Created on: 07.07.2018
+ *      Author: eyck
+ */
+
+#ifndef RISCV_SC_INCL_SYSC_GENERAL_TERMINAL_H_
+#define RISCV_SC_INCL_SYSC_GENERAL_TERMINAL_H_
+
+#include "scc/signal_target_mixin.h"
+#include "scc/signal_initiator_mixin.h"
+#include "tlm/tlm_signal.h"
+#include "cci_configuration"
+#include <sysc/kernel/sc_module.h>
+#include <memory>
+
+namespace sysc {
+class WsHandler;
+
+class terminal: public sc_core::sc_module {
+public:
+    scc::tlm_signal_logic_out tx_o;
+    scc::tlm_signal_logic_in  rx_i;
+
+    terminal();
+
+    terminal(const sc_core::sc_module_name& nm);
+
+    virtual ~terminal();
+
+    cci::cci_param<bool> write_to_ws;
+
+protected:
+    std::vector<uint8_t> queue;
+    void receive(tlm::tlm_signal_gp<sc_dt::sc_logic>& gp, sc_core::sc_time& delay);
+    std::shared_ptr<sysc::WsHandler> handler;
+    sc_core::sc_time last_tx_start=sc_core::SC_ZERO_TIME;
+};
+}
+
+#endif /* RISCV_SC_INCL_SYSC_GENERAL_TERMINAL_H_ */
diff --git a/riscv.sc/incl/sysc/SiFive/clint.h b/riscv.sc/incl/sysc/SiFive/clint.h
index c4001d5..8ebbfb8 100644
--- a/riscv.sc/incl/sysc/SiFive/clint.h
+++ b/riscv.sc/incl/sysc/SiFive/clint.h
@@ -55,7 +55,8 @@ class core_complex;
 class clint : public sc_core::sc_module, public scc::tlm_target<> {
 public:
     SC_HAS_PROCESS(clint);
-    sc_core::sc_in<sc_core::sc_time> clk_i;
+    sc_core::sc_in<sc_core::sc_time> tlclk_i;
+    sc_core::sc_in<sc_core::sc_time> lfclk_i;
     sc_core::sc_in<bool> rst_i;
     sc_core::sc_out<bool> mtime_int_o;
     sc_core::sc_out<bool> msip_int_o;
diff --git a/riscv.sc/incl/sysc/SiFive/core_complex.h b/riscv.sc/incl/sysc/SiFive/core_complex.h
index b60a920..669c4d4 100644
--- a/riscv.sc/incl/sysc/SiFive/core_complex.h
+++ b/riscv.sc/incl/sysc/SiFive/core_complex.h
@@ -109,7 +109,8 @@ public:
     ~core_complex();
 
     inline void sync(uint64_t cycle) {
-        quantum_keeper.inc(curr_clk*(cycle-last_sync_cycle));
+        auto time = curr_clk*(cycle-last_sync_cycle);
+        quantum_keeper.inc(time);
         if (quantum_keeper.need_sync()) {
             wait(quantum_keeper.get_local_time());
             quantum_keeper.reset();
diff --git a/riscv.sc/incl/sysc/SiFive/gpio.h b/riscv.sc/incl/sysc/SiFive/gpio.h
index 5dd1de3..a4cc267 100644
--- a/riscv.sc/incl/sysc/SiFive/gpio.h
+++ b/riscv.sc/incl/sysc/SiFive/gpio.h
@@ -38,8 +38,10 @@
 #define _GPIO_H_
 
 #include "scc/tlm_target.h"
+#include "scc/signal_target_mixin.h"
+#include "scc/signal_initiator_mixin.h"
+#include <tlm/tlm_signal.h>
 #include "cci_configuration"
-#include <sysc/communication/sc_signal_rv_ports.h>
 
 namespace sysc {
 
@@ -51,7 +53,15 @@ public:
     SC_HAS_PROCESS(gpio);
     sc_core::sc_in<sc_core::sc_time> clk_i;
     sc_core::sc_in<bool> rst_i;
-    sc_core::sc_inout_rv<32> pins_io;
+    // sc_core::sc_inout_rv<32> pins_io;
+
+    sc_core::sc_vector<scc::tlm_signal_logic_out> pins_o;
+    sc_core::sc_vector<scc::tlm_signal_logic_in>  pins_i;
+
+    sc_core::sc_vector<scc::tlm_signal_bool_opt_out> iof0_o;
+    sc_core::sc_vector<scc::tlm_signal_bool_opt_out> iof1_o;
+    sc_core::sc_vector<scc::tlm_signal_bool_opt_in>  iof0_i;
+    sc_core::sc_vector<scc::tlm_signal_bool_opt_in>  iof1_i;
 
     gpio(sc_core::sc_module_name nm);
     virtual ~gpio() override; // need to keep it in source file because of fwd declaration of gpio_regs
@@ -62,14 +72,13 @@ protected:
     void clock_cb();
     void reset_cb();
     void update_pins();
-    void pins_cb();
     void before_end_of_elaboration();
+    void pin_input(unsigned int tag, tlm::tlm_signal_gp<sc_logic>& gp, sc_core::sc_time& delay);
+    void forward_pin_input(unsigned int tag, tlm::tlm_signal_gp<sc_logic>& gp);
+    void iof_input(unsigned int tag, unsigned iof_idx, tlm::tlm_signal_gp<>& gp, sc_core::sc_time& delay);
     sc_core::sc_time clk;
     std::unique_ptr<gpio_regs> regs;
     std::shared_ptr<sysc::WsHandler> handler;
-
-private:
-	void update_value_reg();
 };
 
 } /* namespace sysc */
diff --git a/riscv.sc/incl/sysc/SiFive/platform.h b/riscv.sc/incl/sysc/SiFive/platform.h
index 9055c43..cd493c4 100644
--- a/riscv.sc/incl/sysc/SiFive/platform.h
+++ b/riscv.sc/incl/sysc/SiFive/platform.h
@@ -34,8 +34,8 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
-#ifndef SIMPLESYSTEM_H_
-#define SIMPLESYSTEM_H_
+#ifndef _PLATFORM_H_
+#define _PLATFORM_H_
 
 #include "aon.h"
 #include "clint.h"
@@ -44,14 +44,15 @@
 #include "prci.h"
 #include "spi.h"
 #include "uart.h"
-
-#include <array>
-#include <sysc/kernel/sc_module.h>
+#include "core_complex.h"
 
 #include "scc/memory.h"
 #include "scc/router.h"
 #include "scc/utilities.h"
-#include "core_complex.h"
+#include "tlm/tlm_signal_sockets.h"
+#include <sysc/kernel/sc_module.h>
+#include <array>
+
 
 namespace sysc {
 
@@ -59,6 +60,12 @@ class platform : public sc_core::sc_module {
 public:
     SC_HAS_PROCESS(platform);
 
+    sc_core::sc_vector<tlm::tlm_signal_initiator_socket<sc_dt::sc_logic>> pins_o;
+    sc_core::sc_vector<tlm::tlm_signal_target_socket<sc_dt::sc_logic>>    pins_i;
+
+    platform(sc_core::sc_module_name nm);
+
+private:
     SiFive::core_complex i_core_complex;
     scc::router<> i_router;
     uart i_uart0, i_uart1;
@@ -71,13 +78,15 @@ public:
 
     scc::memory<512_MB, 32> i_mem_qspi;
     scc::memory<128_kB, 32> i_mem_ram;
-    sc_core::sc_signal<sc_core::sc_time> s_clk;
+    sc_core::sc_signal<sc_core::sc_time> s_tlclk;
+    sc_core::sc_signal<sc_core::sc_time> s_lfclk;
     sc_core::sc_signal<bool> s_rst, s_mtime_int, s_msie_int;
-    sc_core::sc_vector<sc_core::sc_signal<bool>> s_global_int, s_local_int;
+    sc_core::sc_vector<sc_core::sc_signal<bool, SC_MANY_WRITERS>> s_global_int, s_local_int;
     sc_core::sc_signal<bool> s_core_int;
-    sc_core::sc_signal_rv<32> s_gpio_pins;
+    sc_core::sc_vector<sc_core::sc_signal<bool>> s_dummy;
+    sc_core::sc_vector<scc::tlm_signal_bool_opt_in>  s_dummy_sck_i;
+    sc_core::sc_vector<scc::tlm_signal_bool_opt_out> s_dummy_sck_o;
 
-    platform(sc_core::sc_module_name nm);
 
 protected:
     void gen_reset();
@@ -87,4 +96,4 @@ protected:
 
 } /* namespace sysc */
 
-#endif /* SIMPLESYSTEM_H_ */
+#endif /* _PLATFORM_H_ */
diff --git a/riscv.sc/incl/sysc/SiFive/uart.h b/riscv.sc/incl/sysc/SiFive/uart.h
index 68e6e3e..43fe99e 100644
--- a/riscv.sc/incl/sysc/SiFive/uart.h
+++ b/riscv.sc/incl/sysc/SiFive/uart.h
@@ -37,11 +37,14 @@
 #ifndef _UART_H_
 #define _UART_H_
 
-#include "cci_configuration"
 #include "scc/tlm_target.h"
+#include "scc/signal_target_mixin.h"
+#include "scc/signal_initiator_mixin.h"
+#include <tlm/tlm_signal.h>
+#include "cci_configuration"
 
 namespace sysc {
-
+class tlm_signal_uart_extension;
 class uart_regs;
 class WsHandler;
 
@@ -50,18 +53,28 @@ public:
     SC_HAS_PROCESS(uart);
     sc_core::sc_in<sc_core::sc_time> clk_i;
     sc_core::sc_in<bool> rst_i;
+    scc::tlm_signal_bool_out tx_o;
+    scc::tlm_signal_bool_in  rx_i;
+
+    sc_core::sc_out<bool> irq_o;
+
+    cci::cci_param<bool> write_to_ws;
+
     uart(sc_core::sc_module_name nm);
     virtual ~uart() override;
 
-    cci::cci_param<bool> write_to_ws;
 protected:
     void clock_cb();
     void reset_cb();
     void transmit_data();
+    void receive_data(tlm::tlm_signal_gp<>& gp, sc_core::sc_time& delay);
+    void update_irq();
     void before_end_of_elaboration();
     sc_core::sc_time clk;
     std::unique_ptr<uart_regs> regs;
+    sc_core::sc_fifo<uint8_t> rx_fifo, tx_fifo;
     std::vector<uint8_t> queue;
+    sysc::tlm_signal_uart_extension *rx_ext, *tx_ext;
     std::shared_ptr<sysc::WsHandler> handler;
 };
 
diff --git a/riscv.sc/incl/sysc/tlm_extensions.h b/riscv.sc/incl/sysc/tlm_extensions.h
new file mode 100644
index 0000000..b2f5663
--- /dev/null
+++ b/riscv.sc/incl/sysc/tlm_extensions.h
@@ -0,0 +1,31 @@
+/*
+ * tlm_extensions.h
+ *
+ *  Created on: 12.07.2018
+ *      Author: eyck
+ */
+
+#ifndef RISCV_SC_INCL_SYSC_TLM_EXTENSIONS_H_
+#define RISCV_SC_INCL_SYSC_TLM_EXTENSIONS_H_
+
+#include "tlm/tlm_extensions.h"
+
+namespace sysc {
+struct tlm_signal_uart_extension : public tlm::tlm_unmanaged_extension<tlm_signal_uart_extension> {
+
+    struct uart_tx {
+        unsigned data_bits:4;
+        unsigned stop_bits:2;
+        bool parity:1;
+        unsigned baud_rate:24;
+        unsigned data;
+    } tx;
+    sc_core::sc_time start_time;
+
+};
+
+}
+
+
+
+#endif /* RISCV_SC_INCL_SYSC_TLM_EXTENSIONS_H_ */
diff --git a/riscv.sc/src/CMakeLists.txt b/riscv.sc/src/CMakeLists.txt
index 4e11fc5..89decc0 100644
--- a/riscv.sc/src/CMakeLists.txt
+++ b/riscv.sc/src/CMakeLists.txt
@@ -1,5 +1,5 @@
 # library files
-FILE(GLOB RiscVSCHeaders *.h)
+FILE(GLOB RiscVSCHeaders *.h */*.h)
 FILE(GLOB RiscvSCSources sysc/*.cpp)
 
 set(LIB_HEADERS ${RiscVSCHeaders} )
diff --git a/riscv.sc/src/sc_main.cpp b/riscv.sc/src/sc_main.cpp
index 6ea94cb..3b2a4ce 100644
--- a/riscv.sc/src/sc_main.cpp
+++ b/riscv.sc/src/sc_main.cpp
@@ -37,7 +37,7 @@
 #include <boost/program_options.hpp>
 #include <iss/log_categories.h>
 #include <sstream>
-#include <sysc/SiFive/platform.h>
+#include <sysc/General/system.h>
 #include "scc/configurer.h"
 #include "scc/report.h"
 #include "scc/scv_tr_db.h"
@@ -123,7 +123,7 @@ int sc_main(int argc, char *argv[]) {
     ///////////////////////////////////////////////////////////////////////////
     // instantiate top level
     ///////////////////////////////////////////////////////////////////////////
-    platform i_simple_system("i_simple_system");
+    sysc::system i_system("i_system");
     // sr_report_handler::add_sc_object_to_filter(&i_simple_system.i_master,
     // sc_core::SC_WARNING, sc_core::SC_MEDIUM);
     if(vm["dump-config"].as<std::string>().size()>0){
@@ -134,20 +134,20 @@ int sc_main(int argc, char *argv[]) {
 	cfg.configure();
     // overwrite with command line settings
     if (vm["gdb-port"].as<unsigned short>())
-    	cfg.set_value("i_simple_system.i_core_complex.gdb_server_port", vm["gdb-port"].as<unsigned short>());
+    	cfg.set_value("i_system.i_platform.i_core_complex.gdb_server_port", vm["gdb-port"].as<unsigned short>());
     if (vm.count("dump-ir"))
-    	cfg.set_value("i_simple_system.i_core_complex.dump_ir", vm.count("dump-ir") != 0);
+    	cfg.set_value("i_system.i_platform.i_core_complex.dump_ir", vm.count("dump-ir") != 0);
     if (vm.count("elf"))
-    	cfg.set_value("i_simple_system.i_core_complex.elf_file", vm["elf"].as<std::string>());
+    	cfg.set_value("i_system.i_platform.i_core_complex.elf_file", vm["elf"].as<std::string>());
     if (vm.count("quantum"))
         tlm::tlm_global_quantum::instance().set(sc_core::sc_time(vm["quantum"].as<unsigned>(), sc_core::SC_NS));
     if (vm.count("reset")) {
         auto str = vm["reset"].as<std::string>();
         uint64_t start_address = str.find("0x") == 0 ? std::stoull(str.substr(2), 0, 16) : std::stoull(str, 0, 10);
-        cfg.set_value("i_simple_system.i_core_complex.reset_address", start_address);
+        cfg.set_value("i_system.i_platform.i_core_complex.reset_address", start_address);
     }
     if (vm.count("disass")) {
-        cfg.set_value("i_simple_system.i_core_complex.enable_disass", true);
+        cfg.set_value("i_system.i_platform.i_core_complex.enable_disass", true);
         LOGGER(disass)::reporting_level() = logging::INFO;
         auto file_name = vm["disass"].as<std::string>();
         if (file_name.length() > 0) {
diff --git a/riscv.sc/src/sysc/clint.cpp b/riscv.sc/src/sysc/clint.cpp
index fffcf20..90ec09b 100644
--- a/riscv.sc/src/sysc/clint.cpp
+++ b/riscv.sc/src/sysc/clint.cpp
@@ -47,7 +47,8 @@ const int lfclk_mutiplier = 1 << 12;
 clint::clint(sc_core::sc_module_name nm)
 : sc_core::sc_module(nm)
 , tlm_target<>(clk)
-, NAMED(clk_i)
+, NAMED(tlclk_i)
+, NAMED(lfclk_i)
 , NAMED(rst_i)
 , NAMED(mtime_int_o)
 , NAMED(msip_int_o)
@@ -55,7 +56,7 @@ clint::clint(sc_core::sc_module_name nm)
 , cnt_fraction(0) {
     regs->registerResources(*this);
     SC_METHOD(clock_cb);
-    sensitive << clk_i;
+    sensitive << tlclk_i<<lfclk_i;
     SC_METHOD(reset_cb);
     sensitive << rst_i;
     dont_initialize();
@@ -84,7 +85,7 @@ clint::clint(sc_core::sc_module_name nm)
 
 void clint::clock_cb() {
     update_mtime();
-    this->clk = clk_i.read();
+    clk = lfclk_i.read();
     update_mtime();
 }
 
@@ -101,20 +102,23 @@ void clint::reset_cb() {
 }
 
 void clint::update_mtime() {
-    auto diff = (sc_core::sc_time_stamp() - last_updt) / clk;
-    auto diffi = (int)diff;
-    regs->r_mtime += (diffi + cnt_fraction) / lfclk_mutiplier;
-    cnt_fraction = (cnt_fraction + diffi) % lfclk_mutiplier;
-    mtime_evt.cancel();
-    if (regs->r_mtimecmp > 0)
-    	if(regs->r_mtimecmp > regs->r_mtime && clk > sc_core::SC_ZERO_TIME) {
-    		sc_core::sc_time next_trigger = (clk * lfclk_mutiplier) * (regs->r_mtimecmp - regs->mtime) - cnt_fraction * clk;
-    		LOG(DEBUG)<<"Timer fires at "<< sc_time_stamp()+next_trigger;
-    		mtime_evt.notify(next_trigger);
-    		mtime_int_o.write(false);
-    	} else
-    		mtime_int_o.write(true);
-    last_updt = sc_core::sc_time_stamp();
+    if(clk>SC_ZERO_TIME){
+        uint64_t elapsed_clks = (sc_time_stamp()-last_updt)/clk; // get the number of clock periods since last invocation
+        last_updt += elapsed_clks*clk; // increment the last_updt timestamp by the number of clocks
+        if(elapsed_clks){ // update mtime reg if we have more than 0 elapsed clk periods
+            regs->r_mtime+=elapsed_clks;
+            mtime_evt.cancel();
+            if (regs->r_mtimecmp > 0)
+                if(regs->r_mtimecmp > regs->r_mtime && clk > sc_core::SC_ZERO_TIME) {
+                    sc_core::sc_time next_trigger = (clk * lfclk_mutiplier) * (regs->r_mtimecmp - regs->mtime) - cnt_fraction * clk;
+                    LOG(DEBUG)<<"Timer fires at "<< sc_time_stamp()+next_trigger;
+                    mtime_evt.notify(next_trigger);
+                    mtime_int_o.write(false);
+                } else
+                    mtime_int_o.write(true);
+        }
+    } else
+        last_updt = sc_time_stamp();
 }
 
 } /* namespace sysc */
diff --git a/riscv.sc/src/sysc/gpio.cpp b/riscv.sc/src/sysc/gpio.cpp
index 28eaffa..ecd7d94 100644
--- a/riscv.sc/src/sysc/gpio.cpp
+++ b/riscv.sc/src/sysc/gpio.cpp
@@ -35,7 +35,6 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 #include "sysc/SiFive/gpio.h"
-
 #include "sysc/sc_comm_singleton.h"
 #include "scc/report.h"
 #include "scc/utilities.h"
@@ -48,7 +47,12 @@ gpio::gpio(sc_core::sc_module_name nm)
 , tlm_target<>(clk)
 , NAMED(clk_i)
 , NAMED(rst_i)
-, NAMED(pins_io)
+, NAMED(pins_o, 32)
+, NAMED(pins_i, 32)
+, NAMED(iof0_o, 32)
+, NAMED(iof1_o, 32)
+, NAMED(iof0_i, 32)
+, NAMED(iof1_i, 32)
 , NAMEDD(gpio_regs, regs)
 , NAMED(write_to_ws, false){
     regs->registerResources(*this);
@@ -57,9 +61,36 @@ gpio::gpio(sc_core::sc_module_name nm)
     SC_METHOD(reset_cb);
     sensitive << rst_i;
     dont_initialize();
-    SC_METHOD(pins_cb);
-    sensitive << pins_io;
-
+    auto pins_i_cb =[this](unsigned int tag, tlm::tlm_signal_gp<sc_logic>& gp,
+            tlm::tlm_phase& phase, sc_core::sc_time& delay)->tlm::tlm_sync_enum{
+        this->pin_input(tag, gp, delay);
+        return tlm::TLM_COMPLETED;
+    };
+    auto i=0U;
+    for(auto& s:pins_i){
+        s.register_nb_transport(pins_i_cb, i);
+        ++i;
+    }
+    auto iof0_i_cb =[this](unsigned int tag, tlm::tlm_signal_gp<bool>& gp,
+            tlm::tlm_phase& phase, sc_core::sc_time& delay)->tlm::tlm_sync_enum{
+        this->iof_input(tag, 0, gp, delay);
+        return tlm::TLM_COMPLETED;
+    };
+    i=0;
+    for(auto& s:iof0_i){
+        s.register_nb_transport(iof0_i_cb, i);
+        ++i;
+    }
+    auto iof1_i_cb =[this](unsigned int tag, tlm::tlm_signal_gp<bool>& gp,
+            tlm::tlm_phase& phase, sc_core::sc_time& delay)->tlm::tlm_sync_enum{
+        this->iof_input(tag, 1, gp, delay);
+        return tlm::TLM_COMPLETED;
+    };
+    i=0;
+    for(auto& s:iof1_i){
+        s.register_nb_transport(iof1_i_cb, i);
+        ++i;
+    }
     regs->port.set_write_cb([this](scc::sc_register<uint32_t> &reg, uint32_t data) -> bool {
         if (!this->regs->in_reset()) {
             reg.put(data);
@@ -69,14 +100,6 @@ gpio::gpio(sc_core::sc_module_name nm)
         return true;
     });
 
-    regs->value.set_read_cb([this](const scc::sc_register<uint32_t> &reg, uint32_t& data) -> bool {
-        if (!this->regs->in_reset()) {
-        	// read pins_io and update r_value
-        	update_value_reg();
-            data=reg.get();
-        }
-        return true;
-    });
 }
 
 gpio::~gpio() {}
@@ -100,40 +123,76 @@ void gpio::clock_cb() {
 	this->clk = clk_i.read();
 }
 
-void gpio::pins_cb(){
-	auto inval=pins_io.read();
-	std::string msg(inval.to_string());
-    sc_core::sc_time now = sc_core::sc_time_stamp();
-    if(handler) sc_comm_singleton::inst().execute([this, msg, now](){
-		std::stringstream os;
-		os << "{\"time\":\"" << now << "\",\"data\":\""<<msg<<"\"}";
-		this->handler->send(os.str());
-	});
-}
-
-void gpio::update_value_reg() {
-	// read pins_io and update r_value reg
-	auto inval = pins_io.read();
-	uint32_t res = 0;
-	for (size_t i = 0, msk = 1; i < 32; ++i, msk = msk << 1) {
-		bool bit_set = false;
-		if ((regs->r_input_en & msk) != 0) {
-			if (inval.get_bit(1) == sc_dt::Log_1)
-				bit_set = true;
-			else if (inval.get_bit(1) == sc_dt::Log_Z
-					&& (regs->r_pue & msk) != 0)
-				bit_set = true;
-		}
-		if (bit_set) res |= msk;
-	}
-	regs->r_value = res;
-}
-
 void gpio::update_pins() {
 	sc_core::sc_inout_rv<32>::data_type out_val;
-	for(size_t i=0, msk = 1; i<32; ++i, msk=msk<<1)
-		out_val.set_bit(i, regs->r_output_en&msk?regs->r_port&msk?sc_dt::Log_1:sc_dt::Log_0:sc_dt::Log_Z);
-	pins_io.write(out_val);
+	tlm::tlm_signal_gp<sc_dt::sc_logic> gp;
+	for(size_t i=0, mask = 1; i<32; ++i, mask<<=1){
+	    if((regs->iof_en&mask == 0) || (iof0_i[i].size()==0 && iof1_i[i].size()==0)){
+	        sc_core::sc_time delay{SC_ZERO_TIME};
+            tlm::tlm_phase phase{tlm::BEGIN_REQ};
+            gp.set_command(tlm::TLM_WRITE_COMMAND);
+            gp.set_response_status(tlm::TLM_OK_RESPONSE);
+            gp.set_value(regs->r_output_en&mask?regs->r_port&mask?sc_dt::Log_1:sc_dt::Log_0:sc_dt::Log_Z);
+            pins_o.at(i)->nb_transport_fw(gp, phase, delay);
+	    }
+	}
+}
+
+void gpio::pin_input(unsigned int tag, tlm::tlm_signal_gp<sc_logic>& gp, sc_core::sc_time& delay) {
+    if(delay>SC_ZERO_TIME){
+         wait(delay);
+         delay=SC_ZERO_TIME;
+     }
+     switch(gp.get_value().value()){
+     case sc_dt::Log_1:
+         regs->r_value|=1<<tag;
+         forward_pin_input(tag, gp);
+         break;
+     case sc_dt::Log_0:
+         regs->r_value&=~(1<<tag);
+         forward_pin_input(tag, gp);
+         break;
+     }
+}
+
+void gpio::forward_pin_input(unsigned int tag, tlm::tlm_signal_gp<sc_logic>& gp) {
+    const auto mask = 1U<<tag;
+    if(regs->iof_en&mask){
+        auto& socket = regs->iof_sel&mask?iof1_o[tag]:iof0_o[tag];
+        tlm::tlm_signal_gp<> new_gp;
+        for(size_t i=0; i<socket.size(); ++i){
+            sc_core::sc_time delay{SC_ZERO_TIME};
+            tlm::tlm_phase phase{tlm::BEGIN_REQ};
+            new_gp.set_command(tlm::TLM_WRITE_COMMAND);
+            new_gp.set_response_status(tlm::TLM_OK_RESPONSE);
+            new_gp.set_value(gp.get_value().value()==sc_dt::Log_1);
+            new_gp.update_extensions_from(gp);
+            socket->nb_transport_fw(new_gp, phase, delay); // we don't care about phase and sync enum
+        }
+    }
+}
+
+void gpio::iof_input(unsigned int tag, unsigned iof_idx, tlm::tlm_signal_gp<>& gp, sc_core::sc_time& delay) {
+    if(delay>SC_ZERO_TIME){
+         wait(delay);
+         delay=SC_ZERO_TIME;
+    }
+    const auto mask = 1U<<tag;
+    if(regs->r_iof_en&mask){
+        const auto idx = regs->r_iof_sel&mask?1:0;
+        if(iof_idx == idx){
+            auto& socket = pins_o[tag];
+            for(size_t i=0; i<socket.size(); ++i){
+                sc_core::sc_time delay{SC_ZERO_TIME};
+                tlm::tlm_phase phase{tlm::BEGIN_REQ};
+                tlm::tlm_signal_gp<sc_logic> new_gp;
+                new_gp.set_command(tlm::TLM_WRITE_COMMAND);
+                new_gp.set_value(gp.get_value()?sc_dt::Log_1:sc_dt::Log_0);
+                new_gp.copy_extensions_from(gp);
+                socket->nb_transport_fw(new_gp, phase, delay); // we don't care about phase and sync enum
+            }
+        }
+    }
 }
 
 } /* namespace sysc */
diff --git a/riscv.sc/src/sysc/platform.cpp b/riscv.sc/src/sysc/platform.cpp
index 40d1e9d..5d5241f 100644
--- a/riscv.sc/src/sysc/platform.cpp
+++ b/riscv.sc/src/sysc/platform.cpp
@@ -40,6 +40,8 @@ namespace sysc {
 
 platform::platform(sc_core::sc_module_name nm)
 : sc_core::sc_module(nm)
+, NAMED(pins_o, 32)
+, NAMED(pins_i, 32)
 , NAMED(i_core_complex)
 , NAMED(i_router, 12, 1)
 , NAMED(i_uart0)
@@ -54,12 +56,15 @@ platform::platform(sc_core::sc_module_name nm)
 , NAMED(i_clint)
 , NAMED(i_mem_qspi)
 , NAMED(i_mem_ram)
-, NAMED(s_clk)
+, NAMED(s_tlclk)
 , NAMED(s_rst)
 , NAMED(s_global_int, 256)
 , NAMED(s_local_int, 16)
 , NAMED(s_core_int)
-, NAMED(s_gpio_pins) {
+, NAMED(s_dummy, 16)
+, NAMED(s_dummy_sck_i, 16)
+, NAMED(s_dummy_sck_o, 16)
+{
     i_core_complex.initiator(i_router.target[0]);
     size_t i = 0;
     for (const auto &e : e300_plat_map) {
@@ -72,17 +77,18 @@ platform::platform(sc_core::sc_module_name nm)
     i_router.initiator.at(++i)(i_mem_ram.target);
     i_router.add_target_range(i, 0x80000000, 128_kB);
 
-    i_uart0.clk_i(s_clk);
-    i_uart1.clk_i(s_clk);
-    i_qspi0.clk_i(s_clk);
-    i_qspi1.clk_i(s_clk);
-    i_qspi2.clk_i(s_clk);
-    i_gpio0.clk_i(s_clk);
-    i_plic.clk_i(s_clk);
-    i_aon.clk_i(s_clk);
-    i_prci.clk_i(s_clk);
-    i_clint.clk_i(s_clk);
-    i_core_complex.clk_i(s_clk);
+    i_uart0.clk_i(s_tlclk);
+    i_uart1.clk_i(s_tlclk);
+    i_qspi0.clk_i(s_tlclk);
+    i_qspi1.clk_i(s_tlclk);
+    i_qspi2.clk_i(s_tlclk);
+    i_gpio0.clk_i(s_tlclk);
+    i_plic.clk_i(s_tlclk);
+    i_aon.clk_i(s_tlclk);
+    i_prci.clk_i(s_tlclk);
+    i_clint.tlclk_i(s_tlclk);
+    i_clint.lfclk_i(s_lfclk);
+    i_core_complex.clk_i(s_tlclk);
 
     i_uart0.rst_i(s_rst);
     i_uart1.rst_i(s_rst);
@@ -107,13 +113,25 @@ platform::platform(sc_core::sc_module_name nm)
     i_core_complex.global_irq_i(s_core_int);
     i_core_complex.local_irq_i(s_local_int);
 
-    i_gpio0.pins_io(s_gpio_pins);
+    pins_i(i_gpio0.pins_i);
+    i_gpio0.pins_o(pins_o);
+
+    i_gpio0.iof0_i[17](i_uart0.tx_o);
+    i_uart0.rx_i(i_gpio0.iof0_o[16]);
+    i_uart0.irq_o(s_global_int[3]);
+
+    s_dummy_sck_i[0](i_uart1.tx_o);
+    i_uart1.rx_i(s_dummy_sck_o[0]);
+    i_uart1.irq_o(s_dummy[0]);
 
     SC_THREAD(gen_reset);
+
+    for(auto& sock:s_dummy_sck_i) sock.error_if_no_callback=false;
 }
 
 void platform::gen_reset() {
-    s_clk = 10_ns;
+    s_tlclk = 10_ns;
+    s_lfclk = 30517_ns;
     s_rst = true;
     wait(10_ns);
     s_rst = false;
diff --git a/riscv.sc/src/sysc/system.cpp b/riscv.sc/src/sysc/system.cpp
new file mode 100644
index 0000000..e8212dc
--- /dev/null
+++ b/riscv.sc/src/sysc/system.cpp
@@ -0,0 +1,30 @@
+/*
+ * system.cpp
+ *
+ *  Created on: 11.07.2018
+ *      Author: eyck
+ */
+
+#include "sysc/General/system.h"
+
+using namespace sysc;
+
+system::system(sc_core::sc_module_name nm)
+: sc_module(nm)
+, NAMED(s_gpio, 32)
+, NAMED(i_platform)
+, NAMED(i_terminal)
+{
+  for(auto i=0U; i<s_gpio.size(); ++i){
+      s_gpio[i].in(i_platform.pins_o[i]);
+      i_platform.pins_i[i](s_gpio[i].out);
+  }
+//  i_platform.pins_i(i_platform.pins_o);
+
+  s_gpio[17].out(i_terminal.rx_i);
+  i_terminal.tx_o(s_gpio[16].in);
+}
+
+system::~system() {
+}
+
diff --git a/riscv.sc/src/sysc/terminal.cpp b/riscv.sc/src/sysc/terminal.cpp
new file mode 100644
index 0000000..f4b7115
--- /dev/null
+++ b/riscv.sc/src/sysc/terminal.cpp
@@ -0,0 +1,57 @@
+/*
+ * terminal.cpp
+ *
+ *  Created on: 07.07.2018
+ *      Author: eyck
+ */
+
+#include "sysc/General/terminal.h"
+#include "sysc/sc_comm_singleton.h"
+#include "sysc/tlm_extensions.h"
+#include "scc/report.h"
+
+using namespace sysc;
+
+terminal::terminal() :terminal(sc_core::sc_gen_unique_name("terminal")){
+}
+
+terminal::terminal(const sc_core::sc_module_name& nm)
+: sc_core::sc_module(nm)
+, NAMED(tx_o)
+, NAMED(rx_i)
+, NAMED(write_to_ws, false)
+{
+    rx_i.register_nb_transport([this](
+            tlm::tlm_signal_gp<sc_dt::sc_logic>& gp,
+            tlm::tlm_phase& phase,
+            sc_core::sc_time& delay)->tlm::tlm_sync_enum{
+        this->receive(gp, delay);
+        return tlm::TLM_COMPLETED;
+    });
+}
+
+terminal::~terminal() {
+}
+
+void terminal::receive(tlm::tlm_signal_gp<sc_dt::sc_logic>& gp, sc_core::sc_time& delay) {
+    sysc::tlm_signal_uart_extension* ext;
+    gp.get_extension(ext);
+    if(ext && ext->start_time!=last_tx_start){
+        uint8_t txdata = static_cast<uint8_t>(ext->tx.data);
+        last_tx_start = ext->start_time;
+        if(txdata != '\r') queue.push_back(txdata);
+        if (queue.size() >> 0 && (txdata == '\n' || txdata == 0)) {
+            std::string msg(queue.begin(), queue.end()-1);
+            sc_core::sc_time now = sc_core::sc_time_stamp();
+            if(handler)
+                sysc::sc_comm_singleton::inst().execute([this, msg, now](){
+                    std::stringstream os;
+                    os << "{\"time\":\"" << now << "\",\"message\":\""<<msg<<"\"}";
+                    this->handler->send(os.str());
+                });
+            else
+                LOG(INFO) << this->name() << " receive: '" << msg << "'";
+            queue.clear();
+        }
+    }
+}
diff --git a/riscv.sc/src/sysc/uart.cpp b/riscv.sc/src/sysc/uart.cpp
index f90bd7c..2565f27 100644
--- a/riscv.sc/src/sysc/uart.cpp
+++ b/riscv.sc/src/sysc/uart.cpp
@@ -37,6 +37,7 @@
 #include "sysc/SiFive/uart.h"
 
 #include "sysc/sc_comm_singleton.h"
+#include "sysc/tlm_extensions.h"
 #include "scc/report.h"
 #include "scc/utilities.h"
 #include "sysc/SiFive/gen/uart_regs.h"
@@ -56,25 +57,62 @@ uart::uart(sc_core::sc_module_name nm)
 , tlm_target<>(clk)
 , NAMED(clk_i)
 , NAMED(rst_i)
+, NAMED(tx_o)
+, NAMED(rx_i)
+, NAMED(irq_o)
+, NAMED(write_to_ws, false)
 , NAMEDD(uart_regs, regs)
-, NAMED(write_to_ws, false) {
+{
     regs->registerResources(*this);
     SC_METHOD(clock_cb);
     sensitive << clk_i;
     SC_METHOD(reset_cb);
     sensitive << rst_i;
     dont_initialize();
+    SC_THREAD(transmit_data);
+    rx_i.register_nb_transport([this](tlm::tlm_signal_gp<bool>& gp,
+            tlm::tlm_phase& phase, sc_core::sc_time& delay)->tlm::tlm_sync_enum{
+       this->receive_data(gp, delay);
+       return tlm::TLM_COMPLETED;
+    });
     regs->txdata.set_write_cb([this](scc::sc_register<uint32_t> &reg, uint32_t data) -> bool {
         if (!this->regs->in_reset()) {
             reg.put(data);
-            this->transmit_data();
+            tx_fifo.nb_write(static_cast<uint8_t>(regs->r_txdata.data));
+            regs->r_txdata.full=tx_fifo.num_free()==0;
+            regs->r_ip.txwm=regs->r_txctrl.txcnt<=(7-tx_fifo.num_free())?1:0;
+            update_irq();
         }
         return true;
     });
+    regs->rxdata.set_read_cb([this](const scc::sc_register<uint32_t> &reg, uint32_t& data) -> bool {
+        if (!this->regs->in_reset()) {
+            uint8_t val;
+            if(rx_fifo.nb_read(val)){
+                regs->r_rxdata.data=val;
+                if(regs->r_rxctrl.rxcnt<=rx_fifo.num_available()){
+                    regs->r_ip.rxwm=1;
+                    update_irq();
+                }
+            }
+            data = reg.get()&reg.rdmask;
+        }
+        return true;
+    });
+    regs->ie.set_write_cb([this](scc::sc_register<uint32_t> &reg, uint32_t data) -> bool {
+        update_irq();
+    });
+    regs->ip.set_write_cb([this](scc::sc_register<uint32_t> &reg, uint32_t data) -> bool {
+        update_irq();
+    });
 }
 
 uart::~uart() {}
 
+void uart::update_irq() {
+    irq_o=(regs->r_ip.rxwm==1 && regs->r_ie.rxwm==1) || (regs->r_ip.txwm==1 && regs->r_ie.txwm==1);
+}
+
 void uart::before_end_of_elaboration() {
 	if(write_to_ws.get_value()) {
 	    LOG(TRACE)<<"Adding WS handler for "<<(std::string{"/ws/"}+name());
@@ -95,19 +133,74 @@ void uart::reset_cb() {
 }
 
 void uart::transmit_data() {
-    if(regs->r_txdata.data != '\r') queue.push_back(regs->r_txdata.data);
-    if (queue.size() >> 0 && (regs->r_txdata.data == '\n' || regs->r_txdata.data == 0)) {
-    	std::string msg(queue.begin(), queue.end()-1);
-        LOG(INFO) << this->name() << " transmit: '" << msg << "'";
-        sc_core::sc_time now = sc_core::sc_time_stamp();
-		if(handler)
-			sc_comm_singleton::inst().execute([this, msg, now](){
-				std::stringstream os;
-				os << "{\"time\":\"" << now << "\",\"message\":\""<<msg<<"\"}";
-				this->handler->send(os.str());
-			});
-        queue.clear();
+    uint8_t txdata;
+    sc_core::sc_time delay(SC_ZERO_TIME);
+    tlm::tlm_phase phase(tlm::BEGIN_REQ);
+    tlm::tlm_signal_gp<> gp;
+    gp.set_command(tlm::TLM_WRITE_COMMAND);
+    gp.set_value(true);
+    tx_o->nb_transport_fw(gp, phase, delay);
+    while(true){
+        wait(tx_fifo.data_written_event());
+        while(tx_fifo.nb_read(txdata)){
+            regs->r_txdata.full=tx_fifo.num_free()==0;
+            regs->r_ip.txwm=regs->r_txctrl.txcnt<=(7-tx_fifo.num_free())?1:0;
+            auto bit_duration = (regs->r_div.div+1)*clk;
+            sysc::tlm_signal_uart_extension ext;
+            ext.start_time = sc_core::sc_time_stamp();
+            ext.tx.data_bits=8;
+            ext.tx.parity=false;
+            ext.tx.stop_bits=1+regs->r_txctrl.nstop;
+            ext.tx.baud_rate=static_cast<unsigned>(1/bit_duration.to_seconds());
+            ext.tx.data=txdata;
+            delay=SC_ZERO_TIME;
+            auto start = sc_time_stamp();
+            gp.set_command(tlm::TLM_WRITE_COMMAND);
+            gp.set_value(false);
+            gp.set_extension(&ext);
+            phase=tlm::BEGIN_REQ;
+            tx_o->nb_transport_fw(gp, phase, delay);
+            auto duration = bit_duration*(1+8+1+ext.tx.stop_bits);//start+data+parity+stop
+            auto diff=start+duration-sc_time_stamp();
+            if(diff>SC_ZERO_TIME) wait(diff);
+            delay=SC_ZERO_TIME;
+            gp.set_command(tlm::TLM_WRITE_COMMAND);
+            gp.set_value(true);
+            phase=tlm::BEGIN_REQ;
+            tx_o->nb_transport_fw(gp, phase, delay);
+
+//            if(txdata != '\r') queue.push_back(txdata);
+//            if (queue.size() >> 0 && (txdata == '\n' || txdata == 0)) {
+//                std::string msg(queue.begin(), queue.end()-1);
+//                LOG(INFO) << this->name() << " transmit: '" << msg << "'";
+//                sc_core::sc_time now = sc_core::sc_time_stamp();
+//                if(handler)
+//                    sc_comm_singleton::inst().execute([this, msg, now](){
+//                        std::stringstream os;
+//                        os << "{\"time\":\"" << now << "\",\"message\":\""<<msg<<"\"}";
+//                        this->handler->send(os.str());
+//                    });
+//                queue.clear();
+//            }
+        }
     }
 }
 
+void uart::receive_data(tlm::tlm_signal_gp<>& gp, sc_core::sc_time& delay) {
+    sysc::tlm_signal_uart_extension* ext{nullptr};
+    gp.get_extension(ext);
+    if(ext && ext != rx_ext){
+        auto data = static_cast<uint8_t>(ext->tx.data);
+        if(ext->tx.parity || ext->tx.data_bits!=8) data = rand(); // random value if wrong config
+        rx_fifo.write(data);
+        if(regs->r_rxctrl.rxcnt<=rx_fifo.num_available()){
+            regs->r_ip.rxwm=1;
+            update_irq();
+        }
+        rx_ext=ext; // omit repeated handling of signale changes
+    }
+    gp.set_response_status(tlm::TLM_OK_RESPONSE);
+}
+
 } /* namespace sysc */
+
diff --git a/riscv/incl/iss/arch/riscv_hart_msu_vp.h b/riscv/incl/iss/arch/riscv_hart_msu_vp.h
index 4bcdd52..8b6c509 100644
--- a/riscv/incl/iss/arch/riscv_hart_msu_vp.h
+++ b/riscv/incl/iss/arch/riscv_hart_msu_vp.h
@@ -697,7 +697,7 @@ iss::status riscv_hart_msu_vp<BASE>::read(const iss::addr_t &addr, unsigned leng
         } break;
         case traits<BASE>::RES: {
             auto it = atomic_reservation.find(addr.val);
-            if (it != atomic_reservation.end() && (*it).second != 0) {
+            if (it != atomic_reservation.end() && it->second != 0) {
                 memset(data, 0xff, length);
                 atomic_reservation.erase(addr.val);
             } else
diff --git a/sc-components b/sc-components
index b50df83..019a041 160000
--- a/sc-components
+++ b/sc-components
@@ -1 +1 @@
-Subproject commit b50df83ebfbf06299613a973552856954ed383c1
+Subproject commit 019a04132a8beb7fcab24d504e3347ca0771ea5f
diff --git a/simple-system.json b/simple-system.json
index 250a235..129ef12 100644
--- a/simple-system.json
+++ b/simple-system.json
@@ -1,11 +1,13 @@
 {
 	"i_simple_system":{
-		"i_uart0":{
-			"write_to_ws": true
-		},
-		"i_uart1":{
-			"write_to_ws": false
-		},
-		"i_gpio0.write_to_ws": true
+		"i_platform": {
+			"i_uart0":{
+				"write_to_ws": false
+			},
+			"i_uart1":{
+				"write_to_ws": false
+			},
+			"i_gpio0.write_to_ws": false
+		}
 	}
 }