Cytron Technical Forum

Hi,
I have question regarding to connection between DB9 and max232, according to website in the link below
http://shahrulnizam.com/max232-driver/

There are two convertor of RS232 to UART,
(1) pin11,12,13,14
(2) pin 7,8,9,10

I would like to change a RS232 voltage to UART 5V using MAX232 to interface with SKXBEE
pin RS232>>>>> pin UART
14 (RX,DB9)>>>>> 11(TX SKXBEE,UART)
13 (TX,DB9)>>>>>12(RX SKXBEE,UART)
OR
7(RX,DB9)>>>>> 10(TX SKXBEE,UART)
8(TX,DB9)>>>>> 9 (RX SKXBEE, UART)

Am i right with the above configuration... Please correct me if i am wrong.... TQ

And i hear that for DB9, pin 7 and 8 (request to send and clear to send) need to solder together to allow the transfer of data to MAX232, do it need to solder??? Can someone point out for me???

Thank you sifu sifu in cytron forum....

winfai WROTE:
pin RS232>>>>> pin UART
14 (RX,DB9)>>>>> 11(TX SKXBEE,UART)
13 (TX,DB9)>>>>>12(RX SKXBEE,UART)
OR
7(RX,DB9)>>>>> 10(TX SKXBEE,UART)
8(TX,DB9)>>>>> 9 (RX SKXBEE, UART)

Am i right with the above configuration... Please correct me if i am wrong.... TQ

The MAX232 is just level shifters. The TX UART (TTL) goes in and will come out as TX 232 (+/- 12V). It is not like connecting the PIC UART to a PC serial port where the comunication takes place.

Allen

Hi Allen,
thanks for your reply... My project flow is as following

Electronic module>>>> output (Rs232, DB9)>>>> MAX232 >>>>output (TTL, 5v)>>>> SKXBEE to transfer the data via Zigbee

and the connection between the electronic module ,max232 and SKXBEE as following connection

pin 14 on MAx232 (RX,DB9,electronic module)>>>>> pin 11on MAX232(TX SKXBEE,UART)
pin 13 on MAx232 (TX,DB9,electronic module)>>>>> pin 12 on MAX232(RX SKXBEE,UART)
OR
pin 7 on MAX232(RX,DB9,electronic module)>>>>> pin 10 on MAX232(TX SKXBEE,UART)
pin 8 on MAX232(TX,DB9,electronic module)>>>>> pin 9 on MAX232 (RX SKXBEE, UART)

Is it correct for the configuration??? Please advice me... i am not connecting to any serial port of computer in this case and sorry for the confusion that i have cause....

thank you thank you for all the reply, it is really urgent for me project... can sifu sifu comment on this???

Addition of information,
Actually i only want to shift the voltage level from RS232 to TTL, 5V so that it can work with SKXBEE... TQTQ, can sifu sifu help comment on this...

thank you

refer to this diagram



As above, you can see P11 (T1 in) comes out as P14 (T1out).....T for Tx

But in your naming
P11 (TX UART) comes out as P14 (RX RS232) is where the confusion lies. How does the (TX in) comes out as (RX out)?

Allen

Hi Allen,

Thanks for your reply again... Let me double check with you, there are two RS232 to TTL convertor in MAX232 such as

1. Pin 11 dan 10 are input UART atau UART Transmit,
2. pin 14 dan 7 are output RS232 atau RS232 Receive.
3. Pin 12 dan 9 are output UART atau UART Receive.
3. pin 13 dan 8 are input RS232 atau RS232 Transmit.

If i want to convert from RS232 to TTL (in order to interface with SKXBEE), I must have (UART TX, RS232 RX, UART RX, RS232 TX)

I have RS232 signal to convert to TTL, following is the pin that related to MAX232 connection...

RS232 (DB9) = pin 2 and pin 3 (RX, TX) , pin 5 ground

TTL (SKXBEE) = TX, RX, 5V and ground

My idea now (to convert from RS232 to TTL, so pin 11,12,13,14 on MAX232 has to be chosen)

RS232 (DB9, pin 2, RX)>>>> pin 14 on MAX232 >>> pin 11 on MAX232>>> TTL, 5V, TX
Note: less important, as there are no receive data at RS232 as UART,TX will not output any signal, more appropritae to write in following way
RS232 (DB9, pin 2, RX)<<<< pin 14 on MAX232<<<<pin 11 on MAX232<<<TTL, 5V, TX



RS232 (DB9, pin3, TX)>>>> pin 13 on MAX232>>> pin 12 on MAX232>>> TTL, 5V, RX
Note: Most important , as the data will be transmitted from this pin and it will go to RX of SKXBEE...This is what i cater for as the received data will be transmit out via SKXBEE....

What i know is for connection of RS232 and UART must be "terbalik" that mean RX, UART to TX, RS232 and TX,UART to RX, RS232.... If i am wrong in the connection above, can someone help me to correct it??? I am really appreciate it.... I am confusing with the connection....

Another important question is, will the LED on the RX will be light on for SKXBEE if there are data been received??? I read the manual and it say that only USB data received will light the LED..... As i am interface using UART pin on SKXBEE...???

thanks in advance

winfai WROTE:RS232 (DB9, pin 2, RX)<<<< pin 14 on MAX232<<<<pin 11 on MAX232<<<TTL, 5V, TX

winfai WROTE:RS232 (DB9, pin3, TX)>>>> pin 13 on MAX232>>> pin 12 on MAX232>>> TTL, 5V, RX

The connection looks fine.

winfai WROTE:Another important question is, will the LED on the RX will be light on for SKXBEE if there are data been received??? I read the manual and it say that only USB data received will light the LED..... As i am interface using UART pin on SKXBEE...???

I think the LEDs are connected to the FT232 USB to UART converter chip. So if you are not using USB, it won't light up. However, I'm not sure about it, so I can't confirm...

Thanks for the reply, i still didn't get any signal , now troubleshooting, wonder why the LED light didn't light up.... can anyone confirm me that if i am using the pin interface rather the USB dongle, the light of SKXBee for TX,RX will not light up???

winfai WROTE:Thanks for the reply, i still didn't get any signal , now troubleshooting, wonder why the LED light didn't light up.... can anyone confirm me that if i am using the pin interface rather the USB dongle, the light of SKXBee for TX,RX will not light up???

As the User's Manual of SKXBee stated, the LEDs indicator is for USB communication indicator, not XBee UART.

Now it's clear...thanks Ober!