Hi,

New here.... and would appreciate some insight on the PSOC devices offered by Cypress.

Is there any way to configure a PSOC device to be an RS232 module and then switch it on the fly to be an RS485 I/O module? There are advantages in both but with limited space on my development module I only have space for one connector?

Regards Ian

 232 and 485 has differnet voltage level. Could you be more specific? you need external circuit in both cases.

From what I can gather from your question...

You have room for only one connector on your board. You'd like this to either be RS232 or RS485 and switch it 'on the fly'.

For RS232 you need 3 pins on your connector (TX, RX, and GND) as a minimum and for RS485 you need 2 pins, A and B.

In terms of the connector, you could use some kind of buffer to isolate the two sets of signals, and switch the required ones in and out of the connector, then you'd also need some more hardware (possibly in the PSOC) to multiplex the RX signals (one from the RS232 chip and and from the RS485 chip) as needed.

All of this hardware would take more room than just adding a 2 pin header for RS485.

On eBay you'll find dozens of different USB-to-serial boards which provide RS232 and RS485 options, and they normally do it by means of a bunch of jumpers.

^{Despite to the mentioned voltage levels, you have full control over the pin's states, so you may connect two output pins and enable one of them to perform your needed functionality.}

^Bob

Sometimes something VERY weired goes on in this forum software, what put my last post's lines higher than usual?

Did you accidentially press this 'x2' button in the editor? Your text is enclosed in 'sup' tags, which places them higher...

 You also consider how the other side switch the interface on the fly as well.  Is there any particular reason why you have to have both and switch on fly? A low power 485 linkcan have more then 32 device connected.

This chip may be what you need

LTC1387

RS232 and 485 have quite different physical interfaces, and if you wish to

be complient you need to handle the entire interface, not just 2 or 3 pins.

Additionally the  need to handle the electricals associated with these interfaces.

Even the 9 pin connectors are wired differently.

So from a reliability and PHY aspect external parts seem to be in order to

do this.

Regards, Dana.

I do like this:
 tune UART as RS-232. He uses a TTL signal, and connect the external elements - those that I need. I use this:
http://mylab.wmsite.ru/moi-razrab/ustrojstva-na-usb/usb-rs232_ttl/moduli

To change the baudrate using external clock:

can I change UART baud rate in run time?
http://www.cypress.com/?app=forum&id=2232&rID=60456

Arbitrary BAUD Rate of UART in PSoC 3/5
http://www.cypress.com/?id=4&rID=40116
 

The answer is yes, if using external clock clearly you control the source and /N ratio

using external clock APIs.

If using internal, no APIs shown in data sheet, investigate TRM amnaul for register control

of clock for internal clock.

Regards, Dana.

Looking at the Arch and Register TRM, UART is implemented in UDB blocks,

and there are registers controlling UDB configuration.

That being said no obvious, "pick this", "write this" references to UART configuration.

There are references to clock configuration, so you could experiment.

You could file a tech case at www.cypress.com with the questions on how to config a

UART with internal clock choosen.

Regards, Dana.

If I need an RS-232 and RS-485 I do so as the attached picture:

The original goal was, I believe, two PHYs thru a common connector.

Also your approach can be achieved with more integration today with

parts support both PHYs, seperate connectors. Still does not meet

the goal.

Regards, Dana.

 Have a look of the chip I found. It is 2 PHY in 1 chip.

Yes, this is a good solution  (LTC1387   ) 
http://www.mitracon.ru/pdf/LTC/1387FS.pdf
page 11  figure 14