P87CL888

` Full static asynchronous handshake 80C51 CPU;enhanced 8-bit architecture with:
Standard 80C51 instruction set
CPU speed independent of clock frequency, average speed: 4.8 Mips at 3.0 V
Non-page oriented instructions
Direct addressing
Four 8-byte RAM register banks
Stack depth limited only by available internal RAM (maximum 256 bytes)
Multiply, divide, subtract and compare instructions.
` Twenty source, twenty vector interrupt structure with two
priority levels, polarity and sensitivity choice
` Key pad interrupt:
Edge or level sensitive triggering selectable via software
Enabling low-power and low-EMI keyboard control.
` 32 general purpose I/O pins
` Timer 0 and Timer 1: two standard 16-bit timer/event counters
` Timer 2: 16-bit timer/event counter with capture, compare and auto-reload function
` Watchdog Timer
` Wake-up counter
` Idle and Power-down mode
` 8-kbyte blank One Time Programmable (OTP) memory or factory programmed OTP memory
` In-system programming of OTP memory
` Supply voltage: 1.8 to 3.6 V
` 256 bytes RAM
` Internal crystal oscillator
` Power-on reset circuitry with disable pin
` Reset I/O pin for external reset from master or to slave
` MSK modem including Manchester encoder/decoder with 2 digital outputs (by SW) for analog cordless telephones (standards CT0/CT1/CT1+)
` I²C-bus master/slave (transmitter/receiver, maximum frequency 400 kHz)
` 8 bit digital-to-analog converter with two different outputs
` 6 inputs Comparator with input multiplexer (for successive approximation analog-to-digital conversion).

Besides the special telephony applications as DTMF and MSK, the controller can also be used to perform the following functions:
` Ring level detect; 10 up to 90 V (RMS) superimposed on 48 up to 72 V (DC voltage); level reject range adjustable between 10 to 50 V (RMS)
` Ring frequency detect: 17 to 66 Hz; reject frequencies <14 and >70 Hz; adjustable between 14 to 70 Hz
` Line in use, set 1 (on-hook) indicates that set 2 is off-hook; this means:
V<sub>A/B</sub> < 16 V: line is in use
V<sub>A/B</sub> > 20 V: line is idle
this works only in mains supplied systems, or set 1 (off-hook) indicates its own off-hook mode; this last function works also in line powered sets
` Hold release: set 1 is off-hook. Hold button: set 2 goes off-hook; set 1 disconnects
` Parallel set detect; set 1 (for instance an answering machine) is off-hook; set 2 goes off-hook too; set 1 detects this, stops and goes on-hook
` Busy tone detection
` Battery check.
    The values of these functions are adjustable by external resistors, so it is easy to adjust to the local requirements.

The P87CL888 is manufactured in an advanced CMOS technology. The P87CL888 is a member of the VTELX microcontroller family which is a low-power family of low-voltage 80CL51 microcontrollers with advanced features for telecom applications. The Philips exclusive, asynchronous handshaking technology has been used for the CPU implementation which makes the CPU to run at its maximum speed independent of the used crystal frequency.

The P87CL888 is especially suited for low cost analog cordless telephone applications (CT0, CT1 and CT1+standards) and wired feature phones. For this purpose,functions like ADC/DAC, MSK modem, I2C-bus and key interrupts are integrated on-chip.

The P87CL888 is optimized for low power consumption. It has two software selectable modes for power reduction: Idle and Power-down. In addition, the clock to all unused peripheral blocks can be switched off.

The instruction set is based on that of the 80C51. The P87CL888 also functions as an arithmetic processor having facilities for both binary and BCD arithmetic plus bit-handling capabilities. The instruction set P87CL888 consists of over 100 instructions: 49 one-byte, 46 two-byte, and 16 three-byte. Due to the missing Port P2, there is no external data or memory access and the MOVX operations cannot be used.