upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 426

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

(2)
(3)
(4)
(5)
Cautions: 1. Keep the baud rate error on the transmission side to within the permissible error
426
UARTAn control register 1 (UAnCTL1)
The UAnCTL1 register is used to select the clock for UARTAn.
For details, refer to 12.3 (2) UARTAn control register 1 (UAnCTL1).
UARTAn control register 2 (UAnCTL2)
The UAnCTL2 register is used to select the baud rate (serial transfer rate) clock for UARTAn.
For details, refer to 12.3 (3) UARTAn control register 2 (UAnCTL2).
Baud rate
The baud rate can be calculated by the following expression.
f
k = Value set by UAnBRS7 to UAnBRS0 bits of UAnCTL2 register (k = 4, 5, 6, …, 255)
Error of baud rate
The baud rate error is calculated by the following expression.
Example:
Frequency of base clock = 32 MHz
Selection of f
Set value of UAnBRS7 to UAnBRS0 bits of UAnCTL2 register = 01101000B (k = 52)
Target baud rate = 153600 bps
Baud rate
Error
XCLK
= Frequency of base clock selected by UAnCKS3 to UAnCKS0 bits of UAnCTL1 register
2. Keep the baud rate error on the reception side to within the range described in (7)
on the reception side.
Permissible baud rate range for reception.
XX
Error (%) =
= (32000000 / 2) / (2 ¥ 52)
= 153846 [bps]
= (153846/153600 – 1) ¥ 100
= 0.160 [%]
/2 as base clock
Chapter 12 Asynchronous Serial Interface A (UARTA)
(
Actual baud rate (baud rate with error)
Desired baud rate (normal baud rate)
User’s Manual U16702EE3V2UD00
Baud rate =
f
XCLK
2 × k
[bps]
- 1 × 100
)