HD64F38024DV Renesas Electronics America, HD64F38024DV Datasheet - Page 409

• Manufacturer Part Number: HD64F38024DV
• Description: IC H8/SLP MCU FLASH 80QFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8/300L SLPr

Specifications of HD64F38024DV

• Core Processor: H8/300L
• Core Size: 8-Bit
• Speed: 10MHz
• Connectivity: SCI
• Peripherals: LCD, PWM, WDT
• Number Of I /o: 51
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-QFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

(j) Floating-point numbers
(k) File access mode
Floating-point numbers are numbers represented by approximation of real-numbers. In a
C/C++ source program, floating-point numbers are represented by decimal numbers, but
inside the computer they are normally represented by binary numbers.
In the case of binary numbers, the floating-point representation is as follows:
2
Here, n is called the exponent of the floating-point number, and m is called the mantissa.
The number of bits to represent n and m is normally fixed so that a floating-point number
can be represented using a specific data size.
Some terms relating to floating-point numbers are explained below.
(i) Radix
(ii) Rounding
(iii) Normalization
(iv) Guard bit
This is a string that indicates the kind of processing to be carried out on a file when it is
opened. There are 12 different strings, as shown in table 10.31.
n
An integer value indicating the number of distinct digits in the number system used by
a floating-point number (10 for decimal, 2 for binary, etc.). The radix is normally 2.
Rounding is performed when an intermediate result of an operation of higher precision
than a floating-point number is stored as a floating-point number. There is rounding
up, rounding down, and half-adjust rounding (rounding up fractions over 1/2 and
rounding down fractions under 1/2; or, in binary representation, rounding down 0 and
rounding up 1).
When a floating-point number is represented in the form 2 n x m, the same number can
be represented in different ways.
Example: The following two expressions represent the same value.
2
2
Usually, a representation in which the leading digit is not 0 like the former expression
is used, in order to secure the number of valid digits. This is called a normalized
floating-point number, and the operation that converts a floating-point number to this
kind of representation is called normalization.
When saving an intermediate result of a floating-point operation, data one bit longer
than the actual floating-point number is normally provided in order to carry out
rounding. However, this alone does not permit an accurate result to be achieved in the
event of cancellation of significant digits, etc. For this reason, the intermediate result
is saved with an extra bit, called a guard bit.
m (n: integer, m: binary fraction)
5
6
1.0
0.1
(2)
(2)
(
(2)
indicates a binary number)
395