Hello,

I'm new to MCU technology, but have a background in digital electronics since the year 1969. Yes, that's the year 1969 if you're wondering.

I've been studying on my own and have had a lot of success with simple things like turning an LED on and off from an SPI slave device, through an SPI master that's monitoring a switch. However, I'm finding that the settings in MPLAB Easy Setup are not being realized in the PIC16F18855. Changing the SPI clock to something other than 250KHz and clock polarity to "Idle high, active low" results in no change in the clock output of the chip after programming, as measured by O'scope. I've asked Microchip for help by creating a "ticket," but they have no solutions or suggestions and want to close it without resolution.

I don't know where to turn and I'm hoping you might be able to help.

Joe

Hi Joe looking into the specs for modes of operation again may help especially Power-saving-functinality and Flexible-oscillator-structure , also use the correct frequency thru your software.

Dear Joe,

Since you have mentioned that you changed the clock but not seeing its results, I have some suggestions for you:

1. SSPxCON1 reg SSPEN bit to be set, enables SSP. During Initialization, you have to clear, initialize all other settings and then set SSPEN.

2. There are 4 possible clock modes, depending on CKP and CKE bits. Since your system works for 250 kHz, do not change these two bits. However check whether they are right.

3. For programming SPI clock rate, you would have used one of the options, check thoroughly that option is correctly determined and programmed as well.

4. If you have used timer for SPI clock rate, check thoroughly the settings of that timer.

Best Regards,

BV Ramesh.

Is this still an issue? Could you post any relevant sections of the generated code?

I did solve this problem, which was caused entirely by me. . . My desktop computer sits behind the monitors and is somewhat difficult to reach. It’s been that way for some years now. In order to reach the USB ports, I installed an extension cord a long time ago which I ignored and considered as “the computer.” It caused just enough degredation to allow parts of my programs to work and other parts to fail. The funny thing is, I remember Microchip’s warning about the sensitivity of the PICkit4 cable. Nevertheless, since I got a program to work, I eliminated the cable as part of the problem. I have since disconnected the extension cord and all the weird symptoms disappeared.