ST10F269Z1Q6 datasheet(73/184 Pages) STMICROELECTRONICS

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ST10F269

12 - PARALLEL PORTS

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12.6.1 - Alternate Functions of Port 3

The pins of Port 3 serve for various functions which include external timer control lines, the two serial

interfaces and the control lines BHE/WRH and CLKOUT.

The structure of the Port 3 pins depends on their

alternate function (see figures Figure 28 and

Figure 29).

When

the

on-chip

peripheral

associated with a Port 3 pin is configured to use

the alternate input function, it reads the input

latch, which represents the state of the pin, via the

line labeled “Alternate Data Input”. Port 3 pins with

alternate input functions are: T0IN, T2IN, T3IN,

T4IN, T3EUD and CAPIN.

When the on-chip peripheral associated with a

Port 3 pin is configured to use the alternate output

function, its “Alternate Data Output” line is ANDed

with the port output latch line. When using these

alternate functions, the user must set the direction

of the port line to output (DP3.y=1) and must set

the port output latch (P3.y=1). Otherwise the pin is

in its high-impedance state (when configured as

input) or the pin is stuck at '0' (when the port

output latch is cleared). When the alternate output

functions are not used, the “Alternate Data

Output” line is in its inactive state, which is a high

level ('1').

Port 3 pins with alternate output functions are:

T6OUT, T3OUT, TxD0, BHE and CLKOUT.

Table 20 : Port 3 Alternative Functions

Port 3 Pin

Alternate Function

P3.0

P3.1

P3.2

P3.3

P3.4

P3.5

P3.6

P3.7

P3.8

P3.9

P3.10

P3.11

P3.12

P3.13

P3.14

P3.15

T0IN

CAPCOM1 Timer 0 Count Input

T6OUT

Timer 6 Toggle Output

CAPIN

GPT2 Capture Input

T3OUT

Timer 3 Toggle Output

T3EUD

Timer 3 External Up/Down Input

T4IN

Timer 4 Count Input

T3IN

Timer 3 Count Input

T2IN

Timer 2 Count Input

MRST

SSC Master Receive / Slave Transmit

MTSR

SSC Master Transmit / Slave Receive

TxD0

ASC0 Transmit Data Output

RxD0

ASC0 Receive Data Input (Output in synchronous mode)

BHE/WRH

Byte High Enable / Write High Output

SCLK

SSC Shift Clock Input/Output

---

No pin assigned

CLKOUT

System Clock Output

Figure 27 : Port 3 I/O and Alternate Functions

Port 3

No Pin