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3.3V Microcontroller 5V Device

Started by Razal December 12, 2008
Hello...

I am using the Cortex M3 ARM Controller STM 32, And my device to be
interfaced is a 5V logic which is having an SPI and needs a signal which is
  1Mhz

I can make a 1Mhz signal in controller using PWM and it is having an SPI
Hardware but both out put is 3.3V but the PINs of STM32 is 5V tollerable.
so the output from the device can be directly connected or with a resistor
in it.

But my problem in i want to connect the following pins

STM32                                        DEVICE

PORT   3.3V ------------------------------>    NSS1 ( 5 V )
PORT   3.3V ------------------------------>    NSS2 ( 5 V )
MISO   3.3V ------------------------------>    MOSI ( 5 V )
M0SI   3.3V <------------------------------    MISO ( 5 V )
CLOCK  3.3V ------------------------------>    CLCOK( 5 V )
PORT   3.3V ------------------------------>    CONTROL PIN 1 ( 5 V )
PORT   3.3V ------------------------------>    CONTROL PIN 1 ( 5 V )
PORT   3.3V <------------------------------    SIGNAL ( 5 V )
PORT   3.3V <------------------------------    SIGNAL ( 5 V )

Please Help me out to Solve this.
Thanks






On 12/12/2008 Razal wrote:

> Hello... > > I am using the Cortex M3 ARM Controller STM 32, And my device to be > interfaced is a 5V logic which is having an SPI and needs a signal > which is 1Mhz > > I can make a 1Mhz signal in controller using PWM and it is having an > SPI Hardware but both out put is 3.3V but the PINs of STM32 is 5V > tollerable. so the output from the device can be directly connected > or with a resistor in it. > > But my problem in i want to connect the following pins > > STM32 DEVICE > > PORT 3.3V ------------------------------> NSS1 ( 5 V ) > PORT 3.3V ------------------------------> NSS2 ( 5 V ) > MISO 3.3V ------------------------------> MOSI ( 5 V ) > M0SI 3.3V <------------------------------ MISO ( 5 V ) > CLOCK 3.3V ------------------------------> CLCOK( 5 V ) > PORT 3.3V ------------------------------> CONTROL PIN 1 ( 5 V ) > PORT 3.3V ------------------------------> CONTROL PIN 1 ( 5 V ) > PORT 3.3V <------------------------------ SIGNAL ( 5 V ) > PORT 3.3V <------------------------------ SIGNAL ( 5 V ) > > Please Help me out to Solve this. > Thanks
http://www.maxim-ic.com/appnotes.cfm/an_pk/1159 -- The Force is dark on one side, light on the other and holds the world together. Hmmm, just like Gaffer Tape then.
On Dec 12, 8:55 am, "Hot Jock" <HotJ...@gmail.com> wrote:
> On 12/12/2008 Razal wrote: > > Hello... > > > I am using the Cortex M3 ARM Controller STM 32, And my device to be > > interfaced is a 5V logic which is having an SPI and needs a signal > > which is 1Mhz > > > I can make a 1Mhz signal in controller using PWM and it is having an > > SPI Hardware but both out put is 3.3V but the PINs of STM32 is 5V > > tollerable. so the output from the device can be directly connected > > or with a resistor in it. > > > But my problem in i want to connect the following pins > > > STM32 DEVICE > > > PORT 3.3V ------------------------------> NSS1 ( 5 V ) > > PORT 3.3V ------------------------------> NSS2 ( 5 V ) > > MISO 3.3V ------------------------------> MOSI ( 5 V ) > > M0SI 3.3V <------------------------------ MISO ( 5 V ) > > CLOCK 3.3V ------------------------------> CLCOK( 5 V ) > > PORT 3.3V ------------------------------> CONTROL PIN 1 ( 5 V ) > > PORT 3.3V ------------------------------> CONTROL PIN 1 ( 5 V ) > > PORT 3.3V <------------------------------ SIGNAL ( 5 V ) > > PORT 3.3V <------------------------------ SIGNAL ( 5 V ) > > > Please Help me out to Solve this. > > Thanks > > http://www.maxim-ic.com/appnotes.cfm/an_pk/1159 >
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=497-1113-2-ND is cheaper at $0.17 vs. http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=MAX3390EEUD%2BT-ND at $1.38
Razal wrote:
> Hello... > > I am using the Cortex M3 ARM Controller STM 32, And my device to be > interfaced is a 5V logic which is having an SPI and needs a signal which is > 1Mhz > > I can make a 1Mhz signal in controller using PWM and it is having an SPI > Hardware but both out put is 3.3V but the PINs of STM32 is 5V tollerable. > so the output from the device can be directly connected or with a resistor > in it. > > But my problem in i want to connect the following pins > > STM32 DEVICE > > PORT 3.3V ------------------------------> NSS1 ( 5 V ) > PORT 3.3V ------------------------------> NSS2 ( 5 V ) > MISO 3.3V ------------------------------> MOSI ( 5 V ) > M0SI 3.3V <------------------------------ MISO ( 5 V ) > CLOCK 3.3V ------------------------------> CLCOK( 5 V ) > PORT 3.3V ------------------------------> CONTROL PIN 1 ( 5 V ) > PORT 3.3V ------------------------------> CONTROL PIN 1 ( 5 V ) > PORT 3.3V <------------------------------ SIGNAL ( 5 V ) > PORT 3.3V <------------------------------ SIGNAL ( 5 V ) >
If the pins on the device are TTL-compatible, you should be able to drive them directly from the 3.3 V output. 3.3 V was chosen precisely so that it could drive a 5 V TTL input (TTL has a weaker HIGH drive than LOW drive.) However, if your device *isn't* TTL-compatible (usually called something like "CMOS only") then you do need a level shifter. -hpa