p2125vps20 Renesas Electronics Corporation., p2125vps20 Datasheet - Page 570

• Manufacturer Part Number: p2125vps20
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 19 Flash Memory (0.18-µm F-ZTAT Version)
• ERROR (1 byte): Error code
(5)
The methods for checking received data are listed below.
1. Input frequency
2. Division ratio
3. Operating frequency
4. Bit rate
Rev. 1.00 Sep. 21, 2006 Page 532 of 658
REJ09B0310-0100
The received value of the input frequency is checked to ensure that it is within the range of the
minimum to maximum frequencies which are available with the clock modes of the specified
device. When the value is out of this range, an input frequency error is generated.
The received value of the division ratio is checked to ensure that it matches the division for the
clock modes of the specified device. When the value is out of this range, a division ratio error
is generated.
Operating frequency is calculated from the received value of the input frequency and the
division ratio. The input frequency is the frequency input to the LSI, and the operating
frequency is the frequency at which the LSI is actually operated. The formula is given below.
The calculated operating frequency should be checked to ensure that it is within the range of
the 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.
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 4%. If the error is more than 4%, a bit rate selection error is generated. The error
is calculated using the following formula:
Receive Data Check
H'11: Checksum error
H'24: Bit rate selection error
H'25: Input frequency error
H'26: Division ratio error
H'27: Operating frequency error
Operating frequency = Input frequency ÷ Division ratio
The rate is not available.
The input frequency is not within the specified range.
The division ratio does not match an available ratio.
The operating frequency is not within the specified range.