fix #56, performance sketch

README.md

@@ -39,7 +39,7 @@ supports 10^5 write cycles (https://docs.arduino.cc/learn/built-in-libraries/eep
 That is a factor of 10 million more write cycles.
 
 
-#### Fujitsu
+### Fujitsu
 
 Types of FRAM tested with this library:
 
@@ -60,7 +60,7 @@ one calls **setSizeBytes(16 \* 1024)** or **setSizeBytes(8 \* 1024)** to set the
 For the FRAM9 and FRAM11 the size problem is solved (hard coded) in their class.
 
 
-#### Ramtron / Cypress / Infineon
+### Ramtron / Cypress / Infineon
 
 Types of FRAM tested with this library:
 
@@ -71,7 +71,20 @@ Types of FRAM tested with this library:
 |  FM24V10     |  128 KB  |    Y     |                        |  FRAM32  |  #49  |  
 
 
-#### Notes
+### Codes on the chip - Fujitsu
+
+The datasheet - MB85RC04_DS501_00057_1v0_E-2329111.pdf - page 20 - provides meaning 
+to the markings on the FRAM devices. 
+The meaning of Environment code is unclear.
+
+```
+RC04:   Product name
+E11900: E1 (Environment code) + 1900 (Year and Week code)
+300:    3 (Factory code) + 00(Trace code)
+```
+
+
+### Notes
 
 - Not all types of FRAM are tested. Please let me know if you have verified one that is not in the list.
 - If there is no deviceID **getSize()** will not work correctly.
@@ -84,7 +97,7 @@ Not tested: expect the **MB85RC1MT** can be addressed with 2 instances of **FRAM
 too with adjacent addresses.
 
 
-#### Related
+### Related
 
 - https://github.com/RobTillaart/I2C_EEPROM  (eeprom)
 - https://github.com/RobTillaart/I2C_24LC1025  (eeprom)

examples/testFRAMPerformance/testFRAMPerformance.ino

@@ -56,27 +56,28 @@ void loop()
 
 void testReadWriteLarge()
 {
+  int size = 600 * sizeof(int);
   for (int i = 0; i < 600; i++) ar[i] = i;
 
   start = micros();
-  fram.write(1000, (uint8_t*)ar, 1200);
+  fram.write(1000, (uint8_t*)ar, size);
   stop = micros();
   Serial.print("WRITE 1200 bytes TIME: \t");
   Serial.print(stop - start);
   Serial.print(" us ==> \t");
-  Serial.print((stop - start) / 1200.0, 2);
+  Serial.print((stop - start) / (1.0 * size), 2);
   Serial.println(" us/byte.");
   delay(100);
 
   for (int i = 0; i < 600; i++) ar[i] = 0;
 
   start = micros();
-  fram.read(1000, (uint8_t*)ar, 1200);
+  fram.read(1000, (uint8_t*)ar, size);
   stop = micros();
   Serial.print("READ 1200 bytes TIME: \t");
   Serial.print(stop - start);
   Serial.print(" us ==> \t");
-  Serial.print((stop - start) / 1200.0, 2);
+  Serial.print((stop - start) / (1.0 * size), 2);
   Serial.println(" us/byte.");
   delay(100);