Philips Semiconductors

User’s Manual - Preliminary -

 

 

 

 

 

 

KEYPAD INTERRUPT (KBI)

P89LPC901/902/903

 

 

11. KEYPAD INTERRUPT (KBI)

 

 

The Keypad Interrupt function is intended primarily to allow a single interrupt to be generated when the Port 0 bits are equal to or not equal to a certain pattern. This function can be used for keypad recognition. The user can configure the port via SFRs for different tasks.

There are three SFRs used for this function. The Keypad Interrupt Mask Register (KBMASK) is used to define which input pins connected to Port 0 are enabled to trigger the interrupt. The Keypad Pattern Register (KBPATN) is used to define a pattern that is compared to the value of Port 0. The Keypad Interrupt Flag (KBIF) in the Keypad Interrupt Control Register (KBCON) is set when the condition is matched while the Keypad Interrupt function is active. An interrupt will be generated if it has been enabled by setting the EKBI bit in IEN1 register and EA = 1. The PATN_SEL bit in the Keypad Interrupt Control Register (KBCON) is used to define equal or not-equal for the comparison.

In order to use the Keypad Interrupt as an original KBI function like in the 87LPC76x series, the user needs to set KBPATN = 0FFH and PATN_SEL = 0 (not equal), then any key connected to Port0 which is enabled by KBMASK register will cause the hardware to set KBIF = 1 and generate an interrupt if it has been enabled. The interrupt may be used to wake up the CPU from Idle or Power down modes. This feature is particularly useful in handheld, battery powered systems that need to carefully manage power consumption yet also need to be convenient to use.

In order to set the flag and and cause an interrupt, the pattern on Port 0 must be held longer than 6 CCLKs.

KBPATN

 

7

6

5

4

3

 

2

1

0

 

Address: 93h

 

 

-

-

KBPATN.5

KBPATN.4

-

 

-

-

-

 

Not bit addressable

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset Source(s): Any reset

 

 

 

 

 

 

 

 

 

 

 

Reset Value: 11111111B

 

 

 

 

 

 

 

 

 

 

 

BIT

SYMBOL

FUNCTION

 

 

 

 

 

 

 

 

 

KBPATN.5,4

-

Pattern bit 5, bit 4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 11-1: Keypad Pattern Register- P89LPC901

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

KBPATN

 

7

6

5

4

3

 

2

1

0

 

Address: 93h

 

 

-

KBPATN.6

KBPATN.5

KBPATN.4

-

 

KBPATN.2

-

KBPATN.0

 

Not bit addressable

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset Source(s): Any reset

 

 

 

 

 

 

 

 

 

 

 

Reset Value: 11111111B

 

 

 

 

 

 

 

 

 

 

 

BIT

SYMBOL

FUNCTION

 

 

 

 

 

 

 

 

 

KBPATN.6-4,2,0

-

Pattern bit 6 - bit 4, bit 2, bit 0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 11-2: Keypad Pattern Register - P89LPC902

2003 Dec 8

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Philips P89LPC903, P89LPC901, P89LPC902 user manual Kbpatn, KBPATN.5,4
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P89LPC903, P89LPC902, P89LPC901 specifications

The Philips P89LPC901, P89LPC902, and P89LPC903 are a series of 8-bit microcontrollers designed for embedded system applications. These models, which belong to the LPC900 series, are notable for their affordability and versatility, making them an attractive choice for both hobbyists and professional developers.

One of the core features of the P89LPC901, P89LPC902, and P89LPC903 microcontrollers is their powerful 8-bit architecture. Operating at clock speeds up to 20 MHz, they deliver efficient performance suited for a range of tasks. Each model includes a comprehensive instruction set that supports various data manipulation and arithmetic functions, enabling extensive programming capabilities.

These microcontrollers come with built-in memory, with configurations that vary among the three models. The P89LPC901 typically features 4 KB of Flash memory and 256 bytes of RAM, while the P89LPC902 and P89LPC903 offer enhanced memory options. This Flash memory allows for reprogrammability, making it easier to update and modify applications as needed.

Another significant characteristic of the LPC900 series is their integrated peripherals. These models are equipped with a variety of I/O ports, allowing for easy interfacing with other devices and components. The P89LPC901 supports up to 32 I/O pins, while the P89LPC902 and P89LPC903 provide additional features such as analog-to-digital converters (ADCs), timers, and serial communication interfaces. This broad range of peripherals empowers developers to design complex applications without needing extra hardware.

Power consumption is also a key consideration for microcontroller applications. The P89LPC901, P89LPC902, and P89LPC903 are designed with low power consumption in mind, making them ideal for battery-operated devices and energy-efficient projects. They can operate in various power modes, allowing for greater flexibility in deployment.

In terms of technology, these microcontrollers utilize advanced CMOS technology, ensuring high reliability and durability. Their design offers a robust solution for numerous applications, including consumer electronics, industrial controls, and automation systems.

In summary, the Philips P89LPC901, P89LPC902, and P89LPC903 microcontrollers present an attractive combination of performance, integrated peripherals, low power consumption, and versatility. Their features cater to a wide array of applications, keeping them relevant in a rapidly evolving technology landscape. For hobbyists and professionals alike, these microcontrollers represent a reliable foundation for embedded system development.
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