ST10F280 datasheet(85/186 Pages) STMICROELECTRONICS

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ST10F280

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12.5.1 - 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 port structure of the Port 3 pins depends on

their alternate function (see Figure 36).

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 func-

tions 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 out-

put 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 and CLKOUT.

Table 16 : 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 35 : Port 3 I/O and Alternate Functions

Port 3

No Pin