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How to get a 5V output with STR750 EVAL

xaviooo
Associate II
Posted on May 08, 2007 at 08:34

How to get a 5V output with STR750 EVAL

7 REPLIES 7
xaviooo
Associate II
Posted on April 27, 2007 at 10:07

I'm using STR750 Eval board and the example : STR75xStdLib/example/GPIO.

Of course I changed this (instead of 3V3) :

/* GPIO pins optimized for 5V operation */

MRCC_IOVoltageRangeConfig(MRCC_IOVoltageRange_5V);

Then :

/* P2.19 and P2.18 in Push Pull mode */

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_18 | GPIO_Pin_19;

GPIO_Init(GPIO2, &GPIO_InitStructure);

GPIO_Write(GPIO2, 0x00);

-----------------------------------------

I get a 3.3V output on 2.19 (CN7).

-----------------------------------------

What's wrong ? Is there a mask to change ?

I'm using a power supply jack (5V).

JP1 : PSU and DTB fitted.

JP3 : CPU_3V3 fitted.

JP4, JP5, JP6 : not fitted.

Thank you in advance.

mohamed23
Associate II
Posted on April 27, 2007 at 13:14

Hello Xavio,

I think that you have made a misunderstanding about 5Volts subject.

STR75x from ST is 5 Volts tolerant this does not mean that It will output

5volts but it Handles 5 Volts inputs and the output is always 3.3Volts.

If you are interesting to have 5 Volts output, you can use the STR73x series from ST which I found the only ones within the ARM7 micros in market able to drive directly 5volts outputs.

I hope this may help you and make things more clear :-]

bR,

Rave

javidaboo
Associate II
Posted on April 28, 2007 at 05:21

STR750 can operation as either a 5 volt or 3.3 volt device, the I/O output will be at the supply voltage level minus a diode drop.

The only difference on the schematic between 3.3 (Scheme 1) and 5.0 (Scheme 3) is providing 5 instead of 3.3 volts.

I choice to use the 735 device when I started (before the 750 was available) so I can't help you without looking into the library.

Could you please post the answer when you discover the problem.

Barry

xaviooo
Associate II
Posted on April 28, 2007 at 12:55

Well, i'm still confused... especially when I look at this scheme 3 :

0690X00000602eWQAQ.jpg

Xavio

[ This message was edited by: Xavio on 28-04-2007 16:44 ]

xaviooo
Associate II
Posted on May 02, 2007 at 05:23

Well, I can't find a solution.

Barry, are you sure that it's possible to get a 5V output with the STR750 Eval ?

Rave said that it's not possible...

I'm still trying, I don't want to design another board :p

-Xavier

javida14
Associate II
Posted on May 07, 2007 at 20:37

I went to a semimar when they were presenting the device and that what they indicated. The USB could not be used at 5 volts. That was the only difference. Can I say with 100%, NO, but everything that I read indicates, YES.

I choose to go with the 735 part, because KEIL at that time has simulation for all the on-chip peripherals for the 73x and not the 75x family, and I needed the additional I/O at 5 volts.

Have you tried contacting ST Tech Support. They are suppose to be moniting this site, but its looks like there not.

Barry

mohamed23
Associate II
Posted on May 08, 2007 at 08:34

Hi all,

Well, I haven't seen that the STR75x can operate in Dual Supply with (scheme3).

Here attached the confirmation that you can have a minimum I/O output at (VDDIO- 0.8) from STR75x Datasheet : So , Yes it is possible.

However, if you have the STR750-EVAL from STMicroelectronics, It seems that the scheme3 is not implemented and you have to rework the board or to design your own board with Scheme3 model to have 5 Volts Outputs.

BR,

Rave

________________

Attachments :

my.JPG : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006HtG5&d=%2Fa%2F0X0000000aKn%2FuLX54vvr4cvPSRiMvS0NHKFnuqW3CT39319cUfIiQak&asPdf=false