HD64F2168 Datasheet, PDF (722/874 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

• ERROR: (1 byte): Error code
H'11:
H'24:
Sum checking error
Bit-rate selection error
The rate is not available.
H'25: Error in input frequency
This input frequency is not within the specified range.
H'26: Multiplication-ratio error
The ratio does not match an available ratio.
H'27: Operating frequency error
The frequency is not within the specified range.
(5) Received Data Check
The methods for checking of received data are listed below.
1. Input frequency
The received value of the input frequency is checked to ensure that it is within the range of
minimum to maximum frequencies which matches the clock modes of the specified device. When
the value is out of this range, an input-frequency error is generated.
2. Multiplication ratio
The received value of the multiplication ratio or division ratio is checked to ensure that it matches
the clock modes of the specified device. When the value is out of this range, an multiplication-
ratio error is generated.
3. Operating frequency
Operating frequency is calculated from the received value of the input frequency and the
multiplication or division ratio. The input frequency is input to the LSI and the LSI is operated at
the operating frequency. The expression is given below.
Operating frequency = Input frequency × Multiplication ratio, or
Operating frequency = Input frequency ÷ Division ratio
The calculated operating frequency should be checked to ensure that it is within the range of
minimum to maximum frequencies which are available with the clock modes of the specified
device. When it is out of this range, an operating frequency error is generated.
4. Bit rate
To facilitate error checking, the value (n) of clock select (CKS) in the serial mode register (SMR),
and the value (N) in the bit rate register (BRR), which are found from the peripheral operating
clock frequency (φ) and bit rate (B), are used to calculate the error rate to ensure that it is less than
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