AT89C5131A-S3SUL Atmel, AT89C5131A-S3SUL Datasheet - Page 85

• Manufacturer Part Number: AT89C5131A-S3SUL
• Description: MCU 8051 32K FLASH USB 52-PLCC
• Manufacturer: Atmel
• Series: AT89C513xr

Specifications of AT89C5131A-S3SUL

• Core Processor: C52X2
• Core Size: 8-Bit
• Speed: 48MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: LED, POR, PWM, WDT
• Number Of I /o: 34
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 1.25K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 52-PLCC
• Processor Series: AT89x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 1.25 KB
• Interface Type: 2-Wire, EUART, SPI, USB
• Maximum Clock Frequency: 48 MHz
• Number Of Programmable I/os: 34
• Number Of Timers: 3 bit
• Operating Supply Voltage: 3 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: AT89STK-05
• Minimum Operating Temperature: - 40 C
• For Use With: AT89STK-10 - KIT EVAL APPL MASS STORAGEAT89STK-05 - KIT STARTER FOR AT89C5131
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Converters: -
• Lead Free Status / Rohs Status: Details

Keyboard Interface
Introduction
Description
Interrupt
4338F–USB–08/07
The AT89C5131A-L implements a keyboard interface allowing the connection of a 8 x n
matrix keyboard. It is based on 8 inputs with programmable interrupt capability on both
high or low level. These inputs are available as an alternate function of P1 and allow to
exit from idle and power down modes.
The keyboard interface communicates with the C51 core through 3 special function reg-
isters: KBLS, the Keyboard Level Selection register (Table 70), KBE, The Keyboard
interrupt Enable register (Table 69), and KBF, the Keyboard Flag register (Table 68).
The keyboard inputs are considered as 8 independent interrupt sources sharing the
same interrupt vector. An interrupt enable bit (KBD in IE1) allows global enable or dis-
able of the keyboard interrupt (see Figure 40). As detailed in Figure 41 each keyboard
input has the capability to detect a programmable level according to KBLS.x bit value.
Level detection is then reported in interrupt flags KBF.x that can be masked by software
using KBE.x bits.
This structure allow keyboard arrangement from 1 by n to 8 by n matrix and allow usage
of P1 inputs for other purpose.
Figure 40. Keyboard Interface Block Diagram
Figure 41. Keyboard Input Circuitry
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P1:x
Input Circuitry
Input Circuitry
Input Circuitry
Input Circuitry
Input Circuitry
Input Circuitry
Input Circuitry
Input Circuitry
Vcc
Internal Pull-up
KBLS.x
0
1
KBF.x
KBD
IE1.0
KBE.x
Keyboard Interface
Interrupt Request
KBDIT
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