How to get a 5V output with STR750 EVAL

[xaviooo]

Posted on May 08, 2007 at 08:34

How to get a 5V output with STR750 EVAL

[xaviooo]

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]

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]

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]

Posted on April 28, 2007 at 12:55

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

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

[xaviooo]

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]

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]

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