I'm using an 18F4550. I have a SPI IC and a UART IC. Most of you who have used a 4550 know that the RX USART pin is shared with the SDO pin (Pin 1). I'm using the MSSP for the SPI communication.
The best solution that I've found on here is to reconfigure the pin for the function that you need. I'd like to try it to see how much it will slow down the transfer of data but I have some questions.
1. If I'm running the SPI and want to switch to the UART, would I do something like:
3. Are there any other options available? I know switching PIC's seems like an easy solution, and in the end I may switch to a 18F46J50, but if I can make this work I'd prefer to stick with it.
4. The external UART IC runs at 3.3V. I have the 4550 running at 5V. If I want to interface the UART pins, do I put a current limiting resistor in series?
The best solution that I've found on here is to reconfigure the pin for the function that you need. I'd like to try it to see how much it will slow down the transfer of data but I have some questions.
1. If I'm running the SPI and want to switch to the UART, would I do something like:
SSPEN=0
SPEN=1
And then do the reverse when I want to use the SPI again?
2. Can I use other pins for the UART communication? It's not critical data and I only need to check the UART once every 3-4 seconds. SPEN=1
And then do the reverse when I want to use the SPI again?
3. Are there any other options available? I know switching PIC's seems like an easy solution, and in the end I may switch to a 18F46J50, but if I can make this work I'd prefer to stick with it.
4. The external UART IC runs at 3.3V. I have the 4550 running at 5V. If I want to interface the UART pins, do I put a current limiting resistor in series?