Pic 18f2550

[Pepe]

Could someone inform me if there is a replacement for the Pic18f2550 that is pin compatible that does not have usb and ram memory greater than 3kb?

[top204]

That is a bit of a tricky question, because people have their favourite device. However, the PIC18F26K42 and PIC18F27K42 devices are excellent because they are inexpensive and have 4K (26K device) and 8K (27K device) of RAM, and a lot of good peripherals.

About the only thing that Microchip have kept compatability with, to a certain extent, is the pinouts of their device families. :-)

The PIC18F2550 and PIC18F4550 devices were acceptable in their day, but that was about 15 years ago, and if the USB was not used on them, they were actually not so good. :-)

[Pepe]

Thank you for your answer but I need to use the i2c oled library and the pic 18f26k42 does not have MSSP

[tumbleweed]

Of the newer devices, the 18F26Q10 (3615 bytes of ram) still has an MSSP module, and has a few of the newer peripherals too.


There's always the older 18F26K22 (3896 bytes of ram), but they're 2x the price of the Q10.

[Pepe]

thanks for your answers but it has to be pin compatible because I have already made the printed circuit.

[trastikata]

Why are you looking for replacement in this case?

P.s. Go to MICROCHIP ADVANCED PART SELECTOR, select 8-bit PIC MCU "CPU Type", put the min and max pin-count to 28, sort by ram bytes.  Choose a device and compare the pin-out and, voltages and required functionality in the corresponding datasheets.

[top204]

but I need to use the i2c oled library and the pic 18f26k42 does not have MSSP

That is why I do not use the hardware I2C commands in any libraries I create, because Microchip keep altering how the peripherals work. I originally wrote the commands when all the devices available at that time used the same method of controlling the MSSP peripheral, but that has changed so much over the years, I have given up on them. Also, with procedures, a hardware I2C library could be created for particular devices.

The simpler solution is to go into the library code and change the HBus commands with either Bus or I2C commands, then it will work on any PIC device, and at the same speed.

[Pepe]

Thanks again to everyone for your answers, I want to change it to lower costs and also it is increasingly difficult to achieve it. It is being used in a labeller that is already in production and sale a few years ago and in principle it was used because it allowed bootloader by USB but then It was not used, for that reason now I need to replace it without having to redesign the printed circuit since in the pic 18f2550 sda scl they are in RB0 and RB1.

[John Lawton]

Quite a few devices allow you to remap peripheral lines to a range of device pins using PPS, so that might help you when choosing a different device.

[tumbleweed]

Quite a few devices allow you to remap peripheral lines to a range of device pins using PPS

Like the 18F26Q10 that I mentioned. It allows remapping the MSSP to PORTB pins.

If you're looking for something 100% compatible with no firmware changes then I think you're out of luck.