P89LPC980 NXP [NXP Semiconductors], P89LPC980 Datasheet - Page 45

• Manufacturer Part Number: P89LPC980
• Description: 8-bit microcontroller with accelerated two-clock 80C51 core, 4 kB/8 kB wide-voltage byte-erasable flash with 10-bit ADC
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
P89LPC980_982_983_985_2
Preliminary data sheet
7.20.1 Mode 0: 16-bit Timer/Counter with Auto-reload
7.20.2 Mode 1: 16-bit Timer/Counter with Input Capture
7.20.3 Mode 2: 16-bit PWM mode
7.20.4 Timer overflow toggle output
7.22.1 Mode 0
7.21 RTC/system timer
7.22 UART
Mode 0 configures the timer register as an 16-bit Timer/counter with automatic reload. An
overflow upon the timer or a 1-to-0 transition at TxEX pin can cause the reload event.
Mode 1 configures the timer register as an 16-bit Timer/counter with input capture. A
1-to-0 transition at TxEX pin can cause the capture event.
In this mode, the corresponding timer can be changed to a 16-bit PWM generator with
adjustable duty cycle. In this mode, the corresponding timer can be changed to a 16-bit
PWM generator with adjustable duty cycle and adjustable full period (from 0, theoretically,
to 131072).
Timers 2, 3 and 4 can be configured to automatically toggle a port output whenever a
timer overflow occurs. The same device pins that are used for the T2, T3 and T4 count
inputs are 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 P89LPC980/982/983/985 has a simple RTC that allows a user to continue running an
accurate timer while the rest of the device is powered down. The RTC can be a wake-up
or an interrupt source. The RTC is a 23-bit down counter comprised of a 7-bit prescaler
and a 16-bit loadable down counter. When it reaches all logic 0s, the counter will be
reloaded again and the RTCF flag will be set. The clock source for this counter can be
either the CPU clock (CCLK) or the XTAL oscillator. Only power-on reset and watchdog
reset will reset the RTC and its associated SFRs to the default state.
The 16-bit loadable counter portion of the RTC is readable by reading the RTCDATL and
RTCDATH registers.
The P89LPC980/982/983/985 has 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 P89LPC980/982/983/985 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 four modes: shift register, 8-bit UART, 9-bit UART, and CPU
clock/32 or CPU clock/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. 02 — 8 February 2010
8-bit microcontroller with accelerated two-clock 80C51 core
P89LPC980/982/983/985
1
⁄
16
of the CPU clock
© NXP B.V. 2010. All rights reserved.
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