mackrackit's ConnectOne example code

[dhouston]

I'm the other Dave but I'll give you my responses to your questions, anyway.

1. Cross-connect them.

2. The Mini Socket iWiFi datasheet explicitly says to connect CTS/RTS if they are not used but says nothing about DTR/DSR so I don't think you need to connect them but you probably should ask this of Connect One Support.

3. I dropped my intent to make the shield work with 5V and 3.3V because it was just to complicated with all the SPI lines on the other modules. However, with the Mini Socket iWiFi, we are only dealing with two inputs and one output. The way I prefer to handle this is with a transistor and two resistors for each line. You can see example circuits in FIG 15 of AN213.

[mackrackit]

What Dave said...
I will add..
When ConnectOne says TXD to TX they are meaning cross over.

If I were you I would make a point to start designing things for 3.3... But in the mean time
here are more possible solutions, or the same ?
http://ww1.microchip.com/downloads/e...hapter%208.pdf

[dhouston]

I should have mentioned that the Mini Socket iWiFi datasheet says for RXD...

Input - Host Data Receive – Asynchronous serial data received from host.

anf for TXD...

Output - Host Data Send – Asynchronous serial data sent to host.

[jellis00]

I should have mentioned that the Mini Socket iWiFi datasheet says for RXD...anf for TXD...

Thanks, Dave. I also got a Tech Support input from OneConnect saying to connect TXD to MCU's RX and RXD to MCU's Tx, -DTR to ground, -DSR unconnected, and -CTS connected to -RTS. So this clarifies the serial interface requirements for their MiniSocket WiFi module with a PIC MCU.

[jellis00]

What Dave said...
If I were you I would make a point to start designing things for 3.3...

Thanks for the URL to the Tips file. The only reason I am still using 5.0 volts for the MCU is I am using one of the GPIO pins to power on and off a SRF02 Ultrasonic Ranger, which only operates on 5.0v. I am using two LDO regulators, one for 9v to 5.0 v to power the MCU (and the SRF02), and one further downstream for 5.0v to 3.3v to power the ConnectOne WiFi module.

[jellis00]

3. I dropped my intent to make the shield work with 5V and 3.3V because it was just to complicated with all the SPI lines on the other modules. However, with the Mini Socket iWiFi, we are only dealing with two inputs and one output. The way I prefer to handle this is with a transistor and two resistors for each line. You can see example circuits in FIG 15 of AN213.

Other Dave,
I appreciate your referral to this app note...it has a lot of good ideas in it. However, for the level shifting I have to do between the 5V logic on the PIC MCU and the 3.3v logic on the MiniSocket iWiFi module, I am going to give the Sparkfun device a try (see http://www.sparkfun.com/products/8745 ). It is low cost and gives me enough channels to handle the problem. Have you or anyone had any experience with it?

[dhouston]

Have you or anyone had any experience with it?

Yes, I've used it when breadboarding. In fact, I meant to include it in my post but could not find it with a quick search at Spark Fun. (I lost a network drive a few months back which had a lot of my notes, etc. and most of my toys are still in storage after a lengthy hospitalization last year.) It should work fine here.

Also, either the Tips file referenced by mackrackit or a similar one from Microchip (I think.) has tips on getting 5V from 3.3V. For example, if you're using a MAX232 or similar line driver, you can steal 10-12V from it. Of course, it depends on the current needs of your 5V device.