ST6373 datasheet(31/64 Pages) STMICROELECTRONICS

31 / 64 page

ST6373

31/64

I/O PORTS (Cont’d)

4.1.1.2 Output Option Description

Output Option

Port A and B pins in output modes can be set to

Open Drain or Push-Pull modes (not for PA6 and

PA7). Port A bits set to output have a maximum

10mA current sink LED drive capability.

4.1.1.3 I

2C SPI Input/Output

If the user uses the I2C serial peripheral interface,

the I/O lines PA6 and PA7 should be set in output

mode with the open-drain configuration; the corre-

sponding data bit must set to one.

Note. Switching the I/O ports with interrupt (Ports

A and B) from one state to another should be done

in a way that no unwanted side effects can hap-

pen. The recommended safe transitions are

shown below. All other transitions are risky and

should be avoided during change of operation

mode as it is most likely that there will be an un-

wanted side-effect such as interrupt generation or

two pins shorted together by the analog input

lines.

Single bit instructions (SET, RES, JRR and JRS)

should be used very carefully with Port A and B

data registers because these instructions make an

implicit read and write back of the whole ad-

dressed register byte. In port input mode however

data register address reads from input pins, not

from data register latches and data register infor-

mation in input mode is used to set characteristics

of the input pin (interrupt, pull-up, analog input),

therefore these characteristics may be uninten-

tionally reprogrammed, depending on the state of

input pins. As general rule is better to use single bit

instructions on data register only when the whole

port is in output mode. If input or mixed configura-

tion is needed it is recommended to keep a copy of

the data register in RAM. On this copy it is possible

to use single bit instructions, then the copy register

could be written into the port data register.

SET

bit, data copy

a, dataco py

DRA, a

4.1.2 Details of I/O Port C

Port C. When programmed as an input an internal

pull-up can be switched active under program con-

trol. When programmed as an output the Port C

I/O pins will operate in the open-drain mode. PC0-

PC3 are available as open-drain capable of with-

standing a maximum VDD+0.3V. PC4-PC7 are

available as open-drain capable of withstanding

12V and have no resistive pull-up in input mode.

If the user uses the DDC serial peripheral inter-

face, the I/O lines PC0 and PC1 should be set in

output mode while the open-drain configuration is

hardware fixed; the corresponding data bit must

set to one.If the latched interrupt functions are

used (HSYNC,(HSYNC, HDRIVE, PWRIN) then

the corresponding pins should be set to input

mode.

Figure 21. State Transition Diagram for Safe Transitions (Ports A and B)

Note*.xxx = DDR, OR, DR bits respectively

Interrupt

pull-up

Output

Open Drain

Output

Push-pull

Input

pull-up (Reset

state)

Input

Analog

Output

Open Drain

Output

Push-pull

Input

010*

000

100

110

011

001

101

111

ST6373 Folha de dados(PDF) 31 Page - STMicroelectronics

ST6373 Folha de dados(HTML) 31 Page - STMicroelectronics

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

Folha de dados Download

Ligação URL