diff --git a/api/api.cpp b/api/api.cpp
new file mode 100644
index 0000000..27df598
--- /dev/null
+++ b/api/api.cpp
@@ -0,0 +1,63 @@
+#include "api.h"
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <time.h>
+
+#include <sys/poll.h>
+
+#include <pthread.h>
+/*************************************************************************************************/
+UltraSoundDevice::UltraSoundDevice()
+{
+    files[0] = open("/proc/usd_reg_0", O_RDWR, 0);
+    bars[0]= mmap(NULL, 64 * 1024, PROT_READ | PROT_WRITE, MAP_SHARED, files[0], 0);
+
+    files[1] = open("/proc/usd_reg_1", O_RDWR, 0);
+    bars[1]= mmap(NULL, 128 * 1024 * 1024, PROT_READ | PROT_WRITE, MAP_SHARED, files[1], 0);
+}
+
+/*************************************************************************************************/
+UltraSoundDevice::~UltraSoundDevice()
+{
+	munmap(bars[0], 64 * 1024);
+  munmap(bars[1], 128 * 1024 * 1024);
+
+  for(int i = 0; i < BAR_NUM; i++)
+  {
+    close(files[i]);
+  }
+}
+
+/*************************************************************************************************/
+uint8_t UltraSoundDevice::readByte(uint32_t address, uint32_t bar)
+{
+  uint8_t* ptr = (uint8_t*)bars[bar];
+
+  return ptr[address];
+}
+
+/*************************************************************************************************/
+uint32_t UltraSoundDevice::readWord(uint32_t address, uint32_t bar)
+{
+  uint32_t* ptr = (uint32_t*)bars[bar];
+
+  return ptr[address / 4];
+}
+
+/*************************************************************************************************/
+void UltraSoundDevice::writeByte(uint32_t address, uint32_t bar, uint8_t data)
+{
+    uint8_t* ptr = (uint8_t*)bars[bar];
+    ptr[address] = data;
+}
+
+/*************************************************************************************************/
+void UltraSoundDevice::writeWord(uint32_t address, uint32_t bar, uint32_t data)
+{
+    uint32_t* ptr = (uint32_t*)bars[bar];
+    ptr[address / 4] = data;
+}
diff --git a/api/api.h b/api/api.h
new file mode 100644
index 0000000..6bdadb2
--- /dev/null
+++ b/api/api.h
@@ -0,0 +1,21 @@
+#include "stdint.h"
+
+#define BAR_NUM 2
+#define DEV_NAME  "usd_reg"
+
+class UltraSoundDevice 
+{
+private:
+  void* bars[BAR_NUM];
+  int files[BAR_NUM];
+
+public:
+  UltraSoundDevice();
+  ~UltraSoundDevice();
+
+  uint8_t readByte(uint32_t address, uint32_t bar);
+  uint32_t readWord(uint32_t address, uint32_t bar);
+
+  void writeByte(uint32_t address, uint32_t bar, uint8_t data);
+  void writeWord(uint32_t address, uint32_t bar, uint32_t data);
+};
\ No newline at end of file
diff --git a/usdpci.c b/usdpci.c
index 5f71327..8a7e42a 100644
--- a/usdpci.c
+++ b/usdpci.c
@@ -109,7 +109,7 @@ static int __init pcie_init(void)
   bars[0].chrdev_fops.open = usd_open_0;
   bars[0].chrdev_fops.mmap = usd_mmap_0;
   bars[0].chrdev_fops.release = usd_close_0;
-  bars[0].bar_size = 4 * 1024;
+  bars[0].bar_size = 64 * 1024;
 
   bars[1].chrdev_fops.owner = THIS_MODULE;
   bars[1].chrdev_fops.open = usd_open_1;
@@ -200,11 +200,15 @@ static int usd_mmap_0(struct file *filp, struct vm_area_struct *vma)
   unsigned long physical = bars[0].bar_addr + off;
 
   unsigned int intvsize = bars[0].bar_size - off;
-  // these are required for io maps, but is it okay for the buffer as well?
   vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
   vma->vm_flags |= VM_IO;
+
   if ( vsize < intvsize ) 
     intvsize = vsize;
+
+  printk(KERN_ALERT "-----------------------------------\n");
+  printk(KERN_ALERT "BAR0 reg 0 = 0x%x\n", intvsize);
+
   remap_pfn_range(vma, vma->vm_start, physical>>PAGE_SHIFT, intvsize, vma->vm_page_prot);
 
   return 0;
@@ -317,8 +321,19 @@ static int __init pcie_probe (struct pci_dev *dev, const struct pci_device_id *i
 
   pci_set_master(dev);
 
+  void * temp = kmalloc(1024 * 1024 * 4, GFP_KERNEL);
+  u64 phs = virt_to_phys(temp);
+  memset(temp, 0, 1024 * 1024 * 4);
+  int i = 0;
+  u32* counter = (u32*)temp;
+  for ( ; i < 256 * 1024; i++)
+    counter[i] = i;
+  bar0_data[0x82] = phs >> 32;
+  bar0_data[0x83] = phs;
+  bar0_data[0x2002] = 0x8000;
+
   printk(KERN_ALERT "-----------------------------------\n");
-  printk(KERN_ALERT "BAR0 reg 0 = 0x%x\n", *bar0_data);
+  printk(KERN_ALERT "BAR0 reg 0 = 0x%x\n", ioread32(bar0_data));
   *bar1_data = 0x12345678;
   printk(KERN_ALERT "BAR1 reg 0 = 0x%x\n", ioread32(bar1_data));
   printk(KERN_ALERT "-----------------------------------\n");
@@ -362,9 +377,9 @@ static void __exit pcie_exit(void)
   
   char name[16];
   int i = 0;
-  for( ; i < TOTAL_BAR_NUM; i++)
+  for( ;i < TOTAL_BAR_NUM; i++)
   {
-    snprintf(name, 8, "%s%d", DEV_NAME, i);
+    sprintf(name, "%s_%d", DEV_NAME, i);
     remove_proc_entry(name, NULL);
   }