Error at serial transfer start | Fujitsu F202RA, MB89202 guide

CHAPTER 14 8-BIT SERIAL I/O

14.9Notes on Using 8-Bit Serial I/O

This section provides notes on using the 8-bit serial I/O.

■Notes on Using 8-bit Serial I/O

●Error at serial transfer start

The time at which serial I/O transfer is started with a serial transfer program (SMR: SST = 1) is asynchronous with the time when the falling edge (output) or rising (input) edge of a shift clock occurs. For this reason, the time that lasts until the first serial data is input or output is delayed by a maximum of one cycle of the set shift clock.

●Malfunction due to noise

If external noise causes an extra pulse (pulse exceeding the hysteresis width) to be placed on a shift clock during serial data transfer, the 8-bit serial I/O may malfunction.

●Notes on setting via program

•Write data to the serial mode register (SMR) and serial data register (SDR) only when the 8-bit serial I/ O is stopped (SMR: SST = 0).

•When starting or allowing serial I/O transfer (SMR: SST=1), do not change other bits of the SMR.

•If MSB first is set when a shift clock is used in external shift clock input, the highest bit level is output as the SO pin output level. If LSB first is set, the lowest bit level is output as the SO pin output level. MSB first and LSB first are set when the external shift clock is input. In this case, however, serial data output must be allowed (SMR: SOE = 1) even if serial I/O transfer is stopped (SMR: SST = 0).

•If serial I/O transfer stop (SMR: SST = 0) and serial data transfer termination take place at the same

time during serial I/O operation, the interrupt request flag bit (SMR: SIOF) is not set to "1".

•If the SIOF bit is set to "1" and the interrupt request output allowance bit is enabled (SMR: SIOE = 1), control cannot return from interrupt processing. Be sure to clear the SIOF bit.

●Shift clock idle state

The external shift clock must maintain the "H" level during the wait time between one 8-bit data transfer and another (idle state). When the internal shift clock is selected (SMR: CKS1, CKS0 = not 11B) and the P30/UCK/SCK pin is used as the shift clock output pin (SMR: SCKE = 1), data is output at the "H" level in the idle state.

Figure 14.9-1shows the shift clock idle state.

Figure 14.9-1 Shift Clock Idle State

External	Idle state	8-bit data transfer	Idle state	8-bit data transfer	Idle state
shift
clock

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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.

Fujitsu F202RA This section provides notes on using the 8-bit serial I/O, Shift clock idle state

Models: F202RA MB89202