P87C51FB-4A NXP Semiconductors, P87C51FB-4A Datasheet - Page 32

• Manufacturer Part Number: P87C51FB-4A
• Description: Microcontrollers (MCU) 80C51 16K/256 OTP
• Manufacturer: NXP Semiconductors

Specifications of P87C51FB-4A

• Data Bus Width: 8 bit
• Program Memory Type: OTP
• Program Memory Size: 16 KB
• Data Ram Size: 256 B
• Interface Type: UART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 4
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Package / Case: PLCC-44
• Minimum Operating Temperature: 0 C
• Lead Free Status / Rohs Status: Details
• Other names: P87C51FB-4A,512

Philips Semiconductors
(8XC51FX and 8XC51RX+ ONLY)
2000 Aug 07
80C51 8-bit microcontroller family
8K–64K/256–1K OTP/ROM/ROMless, low voltage (2.7V–5.5V),
low power, high speed (33MHz)
INIT_WATCHDOG:
;
;********************************************************************
;
; Main program goes here, but CALL WATCHDOG periodically.
;
;********************************************************************
;
WATCHDOG:
MOV CCAPM4, #4CH
MOV CCAP4L, #0FFH
MOV CCAP4H, #0FFH
ORL CMOD, #40H
CLR EA
MOV CCAP4L, #00
MOV CCAP4H, CH
SETB EA
RET
; Module 4 in compare mode
; Write to low byte first
; Before PCA timer counts up to
; FFFF Hex, these compare values
; must be changed
; Set the WDTE bit to enable the
; Hold off interrupts
; Next compare value is within
; 255 counts of the current PCA
; timer value
; watchdog timer without changing
; the other bits in CMOD
Figure 26. PCA Watchdog Timer Initialization Code
32
8XC51RA+/RB+/RC+/RD+/80C51RA+
8XC51FA/FB/FC/80C51FA
Product specification
8XC54/58