Z86C34 datasheet(26/70 Pages) ZILOG

26 / 70 page

Z86C34/C35/C36/C44/C45/C46

CMOS Z8® MCUs with ASCI UART

ZiLOG

P R E L I M I N A R Y

DS007601-Z8X0499

PIN FUNCTIONS (Continued)

Port 3 (P37–P30).

Port 3 is an 8-bit, CMOS-compatible

port, with four fixed inputs (P33–P30) and four fixed out-

puts (P34–P37). It is configured under software control for

Input/Output, Counter/Timers, interrupt, port handshake,

and Data Memory functions. Port 3, bit 0 input is Schmitt-

triggered, and pins P31, P32, and P33 are standard CMOS

inputs (no Auto Latches). Pins P34, P35, P36, P37 are push-

pull output lines. Low-EMI output buffers can be globally

programmed by the software.

Two onboard comparators can process analog signals on

P31

and P32 with reference to the voltage on P33. The an-

alog function is enabled by programming Port 3 Mode Reg-

ister (P3M bit 1). For Interrupt functions, Port 3, bit 0 and

pin 3 are falling edge interrupt inputs. P31 and P32 are pro-

grammable as rising, falling, or both edge triggered inter-

rupts (IRQ register Bits 6 and 7). P33 is the comparator ref-

erence voltage input when in Analog mode. Access to

Counter/Timers 1 is made through P31 (TIN) and P36

(TOUT). Handshake lines for Ports 0, 1, and 2 are available

on P31 through P36.

Port 3 also provides the following control functions: hand-

shake for Ports 0, 1, and 2 (DAV and RDY); four external

interrupt request signals (IRQ3–IRQ0); timer input and out-

put signals (TIN and TOUT); Data Memory Select (DM, see

Table 10 and Figure 15).

P34

output can be software-programmed to function as a

Data Memory Select (DM). The Port 3 mode register (P3M)

Bit D3,D4 selects this function. When accessing external

Data Memory, the P34 goes active Low; when accessing

external Program Memory, the P34 goes High.

An onboard UART (ASCI) can be enabled by software by

setting the RE and TE bits of the ASCI Control Register A

(CNTLA). When enabled, P30 is the receive input and P37

is the transmit output.

Comparator Inputs and Outputs.

Port 3, pins P31 and

P32

each feature a comparator front end. The comparator

reference voltage, pin P33, is common to both comparators.

In analog mode, the P31 and P32 are the positive inputs to

the comparators and P33 is the reference voltage supplied

to both comparators. In digital mode, pin P33 can be used

as a P33 register input or IRQ1 source. P34 and P37 outputs

the comparator outputs by software-programming the

PCON

Note: The user must add a two-NOP delay after selecting the

P3M

bit D1 to 1 before the comparator output is valid.

IRQ0

, IRQ1, and IRQ2 should be cleared in the IRQ reg-

ister when the comparator is enabled or disabled.

Table 10. Port 3 Pin Assignments

I/O

CTC1

Analog

Int.

P0 HS

P1 HS

P2 HS

Ext

UART

P30

IRQ3

P31

TIN

AN1

IRQ2

D/R

P32

AN2

IRQ0

D/R

P33

REF

IRQ1

D/R

P34

OUT

AN1–OUT

R/D

P35

OUT

R/D

P36

OUT

TOUT

R/D

P37

OUT

AN2–OUT

Notes:

HS = Handshake Signals

D = DAV

R = RDY

Z86C34 Datasheet(PDF) 26 Page - Zilog, Inc.

Z86C34 Datasheet(HTML) 26 Page - Zilog, Inc.

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70

Datasheet Download

Link URL