P89LPC913 PHILIPS [NXP Semiconductors], P89LPC913 Datasheet - Page 37

• Manufacturer Part Number: P89LPC913
• Description: 8-bit microcontrollers with two-clock 80C51 core 1 kB 3 V Flash with 128-byte RAM
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
9397 750 14468
Product data
9.15.4 Mode 3
9.15.5 Mode 6 (P89LPC912, P89LPC914)
9.15.6 Timer overflow toggle output (P89LPC912, P89LPC914)
9.17.1 Mode 0
9.16 Real-Time clock/system timer
9.17 UART (P89LPC913, P89LPC914)
When Timer 1 is in Mode 3 it is stopped. Timer 0 in Mode 3 forms two separate 8-bit
counters and is provided for applications that require an extra 8-bit timer. When
Timer 1 is in Mode 3 it can still be used by the serial port as a baud rate generator.
In this mode, the corresponding timer can be changed to a PWM with a full period of
256 timer clocks.
Timers 0 can be configured to automatically toggle the T0 output whenever a timer
overflow occurs. The same device pins that are used for the T0 count input is also
used for the timer toggle outputs. The port outputs will be a logic 1 prior to the first
timer overflow when this mode is turned on.
The P89LPC912/913/914 devices have a simple Real-Time clock that allows a user
to continue running an accurate timer while the rest of the device is powered-down.
The Real-Time clock can be a wake-up or an interrupt source. The Real-Time clock is
a 23-bit down counter comprised of a 7-bit prescaler and a 16-bit loadable down
counter. When it reaches all ‘0’s, the counter will be reloaded again and the RTCF
flag will be set.
On the P89LPC914 the clock source for this counter is the CPU clock (CCLK). On the
P89LPC912 and P89LPC913 devices, the clock source for this counter can either be
the CPU clock (CCLK) or the XTAL oscillator, provided that the XTAL oscillator is not
being used as the CPU clock. If the XTAL oscillator is used as the CPU clock, then
the RTC will use CCLK as its clock source.
Only power-on reset will reset the Real-Time clock and its associated SFRs to the
default state.
The P89LPC913 and P89LPC914 devices have an enhanced UART that is
compatible with the conventional 80C51 UART except that Timer 2 overflow cannot
be used as a baud rate source. The P89LPC913 does include an independent Baud
Rate Generator. The baud rate can be selected from the oscillator (divided by a
constant), Timer 1 overflow, or the independent Baud Rate Generator. In addition to
the baud rate generation, enhancements over the standard 80C51 UART include
Framing Error detection, automatic address recognition, selectable double buffering
and several interrupt options. The UART can be operated in 4 modes: shift register,
8-bit UART, 9-bit UART, and CCLK/32 or CCLK/16.
Serial data enters and exits through RxD. TxD outputs the shift clock. 8 bits are
transmitted or received, LSB first. The baud rate is fixed at
frequency.
Rev. 03 — 17 December 2004
8-bit microcontrollers with two-clock 80C51 core
P89LPC912/913/914
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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