The MC9S08PA4 ，when powering on, IO is not a high-impedance in PTB4，PTB5

[zbeehu]

i have another problem...

when i power to the PA4,the led will flash,while? Because I program the PA4 find this problem,so i take the PA4 was no program..it also has this problem

[pavel_sadek]

Hi all,

I have added a yellow LED with 470ohm resistor between pin PTB4 and 5V supply.

watchdog is disabled

pin was configured as output (PTBOE4=1) with initial state 0 and PORT_HDRVE_PTB4 = 1;   LED is shining;

when initial state is 1  LED is off

so it behaves correctly

I have placed   PORT_PTBD_PTBD4 = LED_State;  into main loop and by changing of LED_State I am controlling the state of Led on that pin - supply voltage is 5V - I do not see anything incorrect here.

I have tested the behavior across the voltage and did not found the phenomenon you described... device works from 2.5V in my case.

Pavel

[zbeehu]

HI Pavel

i mean the VCC is from 0V-5V

[pavel_sadek]

Hi

you can not use Vcc under 2.7V, oherwise the device does not operate (as it is not properly powered)

Pavel

[zbeehu]

Hi PaveI

when power, the vcc is from 0v-5v, it will  have a little little under 2.7v.

So please look at the issue from the microscopic point of view.

PA32  also have this problem.

But MC9S08QD4，MC9S08SC4 do not have this problem.

[bigmac]

Hello,

This may depend on the POR threshold for the specific type.  When Vdd starts from zero, but remains below the POR threshold voltage, the I/O state is likely indeterminate, since the MCU hardware has not yet commenced to initialise.

Once the POR threshold is exceeded, the MCU hardware will be internally initialised, with I/O defaulting to inputs.  It would then require that Vdd exceed the the default LVD threshold before the clock would start, and code would commence to run.

To minimize this type of issue, the initial application of the Vdd supply should ramp up within a few milliseconds.

To protect against "brown-out", the LVD shold not be disabled.

Regards,

Mac

[zbeehu]

Hi  Mac

When you design the chip hardware why not solve this problem？

[luisburgos]

Hi, can you explain more of your problem please?

How are you programming the PA4?

What do you want to do?

Burgos.

[zbeehu]

I am using this port driver PNP transistors, but when I power up every time, because the port has a sink current pulses, causing the circuit to a PNP transistor opened.

No matter how I programmed PA4, power on, when the transistor is turned on, then off, and time is very short.

So I did not do this experiment PA4 programming, the phenomenon is the same.

[luisburgos]

The image of your schematic is correct? i don't see any transistor there.

If you don´t program PA4 the led turn on? and if you program PA4 with ports in default the led turn on too?

Regards, Burgos.

[zbeehu]

http://v.youku.com/v_show/id_XNjA3ODY5NDUy.html

This is a video I shot.

When the voltage at 1.6V or 1.7V, the red lights,Then the chip not working

while red lights？

[luisburgos]

Hu, what happens if you ups the voltage to 5V?

In 1.7 V you are in Power On Reset (POR) range.

The circuit you are testing is the same of your schematic? I need to know that to help you, i can do tests with a board i have.

Regards, Burgos.

[bbtech]

we confirmed, do have this problem.

[zbeehu]

hi Burgos

Yes,i use this schematic test.

if i ups the voltage to 5V,PTB4，PTB5 will have Sink current pulse!

[pavel_sadek]

Hi Hu

Operating voltage range is 2.7 to 5.5V, so you are out of range here

Pavel

[bbtech]

PTB4, PTB5 support ultra high current output.