L8708H datasheet(21/66 Pages) ZILOG

21 / 66 page

Z86L88/81/86/87/89/73

IR/Low-Voltage Microcontroller

DS96LV00800

P R E L I M I N A R Y

Port 2 (P27-P20). Port 2 is an 8-bit, bidirectional, CMOS

compatible I/O port. These eight I/O lines can be indepen-

dently configured under software control as inputs or out-

puts. Port 2 is always available for I/O operation. A mask

option is available to connect eight 200 kOhms (

±50%)

pull-up resistors on this port. Bits programmed as outputs

are globally programmed as either push-pull or open-

drain. Port 2 may be placed under handshake control. In

this configuration, Port 3 lines, P31 and P36 are used as

the handshake controls lines /DAV2 and RDY2. The hand-

shake signal assignment for Port 3, lines P31 and P36 is

dictated by the direction (input or output) assigned to Bit 7,

Port 2 (Figure 15). The CCP POR resets with the eight bits

of Port 2 configured as inputs with open-drain outputs.

Port 2 also has an 8-bit input OR and an AND gate which

can be used to wake up the part (Figure 41). P20 can be

programmed to access the edge selection circuitry (Figure

24).

Figure 15. Port 2 Conﬁguration

Open-Drain

OEN

Out

PAD

Port 2 (I/O)

Optional

Handshake Controls

/DAV2 and RDY2

(P31 and P36)

Z86LXX

MCU

VCC

200 k

Ω

Mask

Option

L8708H Datasheet(PDF) 21 Page - Zilog, Inc.