Datasheet

Philips Semiconductors Product data

P80C3xX2; P80C5xX2;

P87C5xX2

80C51 8-bit microcontroller family

4K/8K/16K/32K ROM/OTP, low voltage (2.7 to 5.5 V),

low power, high speed (30/33 MHz)

2003 Jan 24

TR2

Control

TL2

(8 bits)

TH2

(8 bits)

TF2

RCAP2L RCAP2H

EXEN2

Control

EXF2

Timer 2

Interrupt

T2EX Pin

Transition

Detector

Capture

SU01622

C/T2 = 0

C/T

2 = 1

*n = 6 in 6-clock mode; n = 12 in 12-clock mode.

OSC

÷ n*

T2 Pin

Figure 7. Timer 2 in Capture Mode

Not Bit Addressable

Symbol Position Function

— Not implemented, reserved for future use.*

T2OE T2MOD.1 Timer 2 Output Enable bit.

DCEN T2MOD.0 Down Count Enable bit. When set, this allows Timer 2 to be configured as an up/down

counter.

— — — — — — T2OE DCEN

SU01519

76543210

* User software should not write 1s to reserved bits. These bits may be used in future 8051 family products to invoke new features.

In that case, the reset or inactive value of the new bit will be 0, and its active value will be 1. The value read from a reserved bit is

indeterminate.

T2MOD Address = 0C9H Reset Value = XXXX XX00B

Figure 8. Timer 2 Mode (T2MOD) Control Register