CHAPTER 13 UART

■Serial Switch

UART and 8-bit serial I/O use the same pins, thus they cannot be simultaneously used. The serial switch circuit needs be used to select either of them.

When UART is selected using the serial switch, P30/UCK/SCK is used as the UART serial clock I/O pin (UCK), P31/UO/SO is used as the UART data output pin (UO), and P32/UI/SI is used as the UART data input pin (UI).

Note:

In this chapter, the pin function switch and register functions are explained on the presupposition that UART is selected using the serial switch circuit.

■Choice of the Transfer Clock Rate

Figure 13.1-1 Baud Rate Generator and Serial Clock Generator

 

 

PR2 to PR0

RC2 to RC0

 

 

 

UART prescaler

 

 

1/2

 

 

 

tINST/2

1/3

1/2

(1/2) n

1

1/4

1/4

1/13

 

 

 

1/5

 

When RC2 and RC1

 

 

 

 

 

 

= 1, the divider is 1

 

 

 

even in asynchronous

 

 

 

mode.

 

PWM output

UCK

tINST : Instruction cycle

CS1, CS0

SMDE

1

1/2

CR

1/8

1/16

1/64

Serial clock

●Example of the baud rates selectable when the dedicated baud rate generator is used

Table 13.1-2 lists the baud rates selectable when the dedicated baud rate generator is used.

Table 13.1-2 Transfer Cycles and Transfer Rates Available for the Dedicated Baud Rate Generator (when FCH = 12.5 MHz)

 

 

 

 

 

Transfer rate (∝s/baud)

 

 

 

 

 

 

 

 

 

 

 

 

Clock divider = 2.5

Clock divider = 1

 

 

 

 

(PR2=0, PR1=1, PR0=0)

(PR2=0, PR1=0, PR0=0)

 

 

 

 

 

 

 

 

RC2

RC1

RC0

Divider for baud rate

Asynchronous

Synchronous

Asynchronous

Synchronous

(multiplier = n)

transfer

transfer

transfer

transfer

 

 

 

 

 

 

 

 

 

 

 

0

0

0

1(0)

83/12019

0.8/1.25M

33/30048

0.32/3.1M

 

 

 

 

 

 

 

 

0

0

1

2(1)

166/6010

1.6/625k

67/15024

0.64/1.6M

 

 

 

 

 

 

 

 

0

1

0

4(2)

333/3005

3.2/313k

133/7512

1.28/781k

 

 

 

 

 

 

 

 

0

1

1

8(3)

666/1503

6.4/156k

266/3756

2.56/391k

 

 

 

 

 

 

 

 

1

0

0

16(4)

1331/751

12.8/78k

532/1878

5.12/195k

 

 

 

 

 

 

 

 

1

0

1

32(5)

2662/375

25.6/39k

1065/939

10.24/98k

 

 

 

 

 

 

 

 

1

1

0

2(1)

13/78125

1.6/625k

5.12/195k

0.64/1.6M

 

 

 

 

 

 

 

 

1

1

1

16(4)

102/9766

12.8/78k

41/24k

5.12/195k

 

 

 

 

 

 

 

 

281

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Image 297
Fujitsu F202RA, MB89202 manual Serial Switch, Choice of the Transfer Clock Rate, 281
Page 296 Page 298

F202RA, MB89202 specifications

The Fujitsu MB89202 and F202RA microcontrollers are part of the 16-bit microcontroller family, renowned for their robust performance and versatility in a variety of embedded system applications. These devices are tailored for high-efficiency operation across diverse industries, including automotive, consumer electronics, and industrial automation.

One of the main features of the MB89202 is its powerful CPU core, which operates at a clock speed of up to 20 MHz. This enables the microcontroller to perform complex calculations and consumer-grade applications seamlessly. The architecture is designed to handle multiple tasks effectively, making it suitable for real-time operations.

Memory capacity is a vital characteristic of the MB89202, featuring on-chip RAM and ROM configurations. The microcontroller can accommodate different memory variants, providing developers with flexibility in memory allocation based on their application requirements. This adaptability facilitates applications ranging from simple control systems to complex data processing tasks.

The F202RA variant extends the capabilities of the MB89202 by integrating advanced peripheral functions. It includes built-in timers, A/D converters, and serial communication interfaces, which are essential for interfacing with other hardware components or sensors. The availability of these peripherals reduces the need for additional external circuits, thus contributing to a more compact and cost-effective design.

In terms of power management, the MB89202 series employs advanced power-saving technologies. The microcontroller offers various low-power modes, enabling devices to conserve energy during idle times, making it highly suitable for battery-operated applications. This characteristic not only enhances the efficiency of devices but also extends their operational lifespan.

Moreover, the Fujitsu MB89202 series incorporates robust protection features, including watchdog timers and failure detection mechanisms. These safety features ensure reliable operation in critical systems, making them a preferred choice in applications where failure is not an option.

The MB89202 and F202RA microcontrollers also support a range of development tools and environments, including integrated development environments (IDEs) and software libraries, which facilitate rapid application development. With these tools, developers can efficiently prototype, debug, and optimize their applications.

In summary, the Fujitsu MB89202 and F202RA microcontrollers stand out with their efficient performance, extensive memory options, integrated peripherals, and power-saving capabilities, making them ideal for a wide array of embedded applications. Their reliability and robustness further enhance their attractiveness for designers seeking advanced microcontroller solutions.
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