first commit

1 files changed, 128 insertions, 0 deletions

diff --git a/m0EEPROM.cpp b/m0EEPROM.cpp
new file mode 100644
index 0000000..10761a7
--- /dev/null
+++ b/m0EEPROM.cpp
@@ -0,0 +1,128 @@
+// m0EEPROM.cpp - implementation of eeprom memory library
+//
+
+#include "Arduino.h"
+#include "Wire.h"
+#include "RingBuffer.h" // for SERIAL_BUFFER_SIZE
+
+#include "m0EEPROM.h
+
+#define PAGE_SIZE 64 // page size of the 24LC256 in bytes
+
+// get the uint log based 2 of the number.
+uint8_t log2uint(uint32_t v) {
+  uint32_t z = 0;
+  while (v >>=1) z++;
+  return z;
+}
+
+// read a byte from the specified address in eeprom memory
+uint8_t eeprom::read_byte(uint16_t address) {
+  uint8_t rdata = 0xFF;
+   
+  Wire.beginTransmission(_device_address);
+  Wire.write((int)(address >> 8));   // MSB
+  Wire.write((int)(address & 0xFF)); // LSB
+         
+  Wire.requestFrom(_device_address,1);
+           
+  if (Wire.available()) rdata = Wire.read();
+             
+  return rdata;
+
+}
+
+// write a single byte of data to the given address in eeprom memory
+void eeprom::write_byte(uint16_t address, uint8_t value) {
+  Wire.beginTransmission(_device_address);
+    
+  Wire.write((int)(address >> 8));   // MSB
+  Wire.write((int)(address & 0xFF)); // LSB
+        
+  Wire.write(data);
+
+  Wire.endTransmission();
+           
+  delay(6); // at least 5ms for quiescence
+}
+
+// read a structure of arbitrary size from address.
+// the size of the structure must be less than 64K-address.
+// returns a byte array of memory specified.  The byte array data
+// must be preallocated to the expected size.
+uint8_t* eeprom::read_bytes(uint16_t start_address, uint8_t* data, uint16_t size) {
+  unsigned char i=0;
+  Wire.beginTransmission(deviceaddress);
+  Wire.write((int)(eeaddress >> 8));   // MSB
+  Wire.write((int)(eeaddress & 0xFF)); // LSB
+  Wire.endTransmission();
+
+  Wire.requestFrom(deviceaddress,num_chars);
+
+  while(Wire.available()) data[i++] = Wire.read();
+
+}
+
+//  write a structure of arbitrary size to memory at address.
+//  the size of the structure must be less than 64K-address.
+//  The structure is passed as a byte array.
+void eeprom::write_bytes(uint16_t address, uint8_t* data, uint16_t size) {
+  // Uses Page Write for 24LC256
+  // Allows for EEPROM_PAGE_SIZE byte page boundary
+  // Splits string into max BUFFER_SIZE byte writes
+//  uint8_t counter=0;
+  unsigned int  address;
+  uint32_t  first_page_len;
+  unsigned int  num_writes;
+//  unsigned int  data_len=0;
+  unsigned char first_write_size;
+  unsigned char last_write_size;  
+  unsigned char write_size;  
+                      
+  // get the amount of memory to write in the first page of eeprom
+  uint8_t page_bits = log2uint(EEPROM_PAGE_SIZE);
+  first_page = ((start_address >> page_bits) +1) * EEPROM_PAGE_SIZE -startaddress;
+  
+  // get the size of the first write based on the I2C buffer size
+  uint8_t buffer_bits = log2uint(SERIAL_BUFFER_SIZE);
+  if (first_page > SERIAL_BUFFER_SIZE){
+      first_write_size = first_page - (first_page >> buffer_bits) * SERIAL_BUFFER_SIZE;
+      if (first_write_size == 0) first_write_size = SERIAL_BUFFER_SIZE;
+  }
+  else
+      first_write_size = first_page;
+
+  // now get the size of the last write in the final page 
+  // and the total number of pages to write.
+  if (size > first_write_size){
+      last_write_size = (size - first_write_size) % SERIAL_BUFFER_SIZE;
+      num_writes = ((data_len - first_write_size) >> (buffer_bits)) + 2;
+  }
+  else
+      num_writes = 1;
+
+  //  Write loop
+  uint8_t i = 0;
+  for (uint32_t page = 0; page < num_writes; ++page){
+      if(page==0) 
+          write_size = first_write_size;
+      else if (page == (num_writes-1)) 
+          write_size = last_write_size;
+      else write_size = SERIAL_BUFFER_SIZE;
+
+      // I2C handshake and comms happens here 
+      Wire.beginTransmission(_device_address);
+      Wire.write((int)((address) >> 8));   // MSB
+      Wire.write((int)((address) & 0xFF)); // LSB
+      for (uint8_t counter=0; counter<write_size; ++counter,++i){
+          Wire.write(data[i]);
+     }
+     Wire.endTransmission();
+     address += write_size;
+
+     delay(6);  // needs 5ms for page write
+}
+
+
+
+