8XC251SA, SB, SP, SQ USER’S MANUAL

Table 9-1. PCA Special Function Registers (SFRs)

Mnemonic

Description

Address

 

 

 

CL

PCA Timer/Counter. These registers serve as a common 16-bit timer or

S:E9H

CH

event counter for the five compare/capture modules. Counts FOSC/12,

S:F9H

 

FOSC/4, timer 0 overflow, or the external signal on P1.2/ECI, as selected by

 

 

CMOD. In PWM mode CL operates as an 8-bit timer.

 

 

 

 

CCON

PCA Timer/Counter Control Register. Contains the run control bit and

S:D8H

 

the overflow flag for the PCA timer/counter, and interrupt flags for the five

 

 

compare/capture modules.

 

 

 

 

CMOD

PCA Timer/Counter Mode Register. Contains bits for disabling the PCA

S:D9H

 

timer/counter during idle mode, enabling the PCA watchdog timer (module

 

 

4), selecting the timer/counter input, and enabling the PCA timer/counter

 

 

overflow interrupt.

 

 

 

 

CCAP0H

PCA Module 0 Compare/Capture Registers. This register pair stores the

S:FAH

CCAP0L

comparison value or the captured value. In the PWM mode, the low-byte

S:EAH

 

register controls the duty cycle of the output waveform.

 

 

 

 

CCAP1H

PCA Module 1 Compare/Capture Registers. This register pair stores the

S:FBH

CCAP1L

comparison value or the captured value. In the PWM mode, the low-byte

S:EBH

 

register controls the duty cycle of the output waveform.

 

 

 

 

CCAP2H

PCA Module 2 Compare/Capture Registers. This register pair stores the

S:FCH

CCAP2L

comparison value or the captured value. In the PWM mode, the low-byte

S:ECH

 

register controls the duty cycle of the output waveform.

 

 

 

 

CCAP3H

PCA Module 3 Compare/Capture Registers. This register pair stores the

S:FDH

CCAP3L

comparison value or the captured value. In the PWM mode, the low-byte

S:EDH

 

register controls the duty cycle of the output waveform.

 

 

 

 

CCAP4H

PCA Module 4 Compare/Capture Registers. This register pair stores the

S:FEH

CCAP4L

comparison value or the captured value. In the PWM mode, the low-byte

S:EEH

 

register controls the duty cycle of the output waveform.

 

 

 

 

CCAPM0

PCA Compare/Capture Module Mode Registers. Contain bits for

S:DAH

CCAPM1

selecting the operating mode of the compare/capture modules and

S:DBH

CCAPM2

enabling the compare/capture flag. See Table 9-3 on page 9-14 for mode

S:DCH

CCAPM3

select bit combinations.

S:DDH

CCAPM4

 

S:DEH

 

 

 

Table 9-2. External Signals

Signal

Type

Description

Alternate

Name

Function

 

 

 

 

 

 

ECI

I

PCA Timer/counter External Input. This signal is the external

P1.2

 

 

clock input for the PCA timer/counter.

 

 

 

 

 

CEX0

I/O

Compare/Capture Module External I/O. Each compare/capture

P1.3

CEX1

 

module connects to a Port 1 pin for external I/O. When not used by

P1.4

CEX2

 

the PCA, these pins can handle standard I/O.

P1.5

CEX3

 

 

P1.6/WAIT#

CEX4

 

 

P1.7/A17/WCLK

 

 

 

 

9-4

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Intel 8XC251SB, 8XC251SA PCA Special Function Registers SFRs, PCA Compare/Capture Module Mode Registers. Contain bits for
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Embedded Microcontroller, 8XC251SP, 8XC251SA, 8XC251SQ, 8XC251SB specifications

The Intel 8XC251 series of embedded microcontrollers is a family of versatile and powerful devices, designed to meet the demands of a wide range of applications. With models such as the 8XC251SB, 8XC251SQ, 8XC251SA, and 8XC251SP, this series offers unique features while maintaining a high level of performance and reliability.

At the heart of the 8XC251 microcontrollers is the 8051 architecture, which provides a 16-bit processor capable of executing complex instructions efficiently. This architecture not only allows for a rich instruction set but also facilitates programming in assembly language and higher-level languages like C, which are essential for developing sophisticated embedded systems.

One of the significant features of the 8XC251 family is its integrated peripherals, including timer/counters, serial communication interfaces, and interrupt systems. These peripherals enable developers to implement timing functions, data communication, and real-time processing, all of which are crucial in modern embedded applications. The 8XC251SB and 8XC251SQ models, for instance, come equipped with multiple I/O ports that allow for interfacing with other devices and systems, enhancing their functionality in various environments.

The memory architecture of the 8XC251 devices is noteworthy, featuring on-chip ROM, RAM, and EEPROM. The on-chip memory allows for fast access times, which is essential for executing programs efficiently. Moreover, the EEPROM serves as non-volatile memory, enabling the storage of configuration settings and important data that must be retained even when power is lost.

In terms of operating voltage, the 8XC251 devices are designed to operate in a wide range, typically between 4.0V and 6.0V. This flexibility makes them suitable for battery-powered applications, where energy efficiency is critical. The power management features, including reduced power modes, further enhance their suitability for portable devices.

Lastly, the 8XC251 series is supported by a wide range of development tools and resources, allowing engineers and developers to streamline the development process. This support, combined with the microcontrollers' robust features, makes the Intel 8XC251 family a reliable choice for various embedded applications, such as industrial automation, automotive systems, and consumer electronics.

Overall, the Intel 8XC251SB, 8XC251SQ, 8XC251SA, and 8XC251SP deliver high performance, versatility, and ease of use, making them a preferred choice for embedded system designers looking to develop efficient and effective solutions.
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