ab. Why PIC18FxxJxx microcontrollers are superior to PIC18Fxxxx microcontrollers?
QUESTION:
Are PIC18Fxxxx microcontroller equaly capable than newer PIC18FxxJxx microcontrollers? Are there any benefits, if I use a K8055N-2 board with a PIC18F2xJ50 microcontroller with the latest PC USB Projects firmware?
ANSWER:
Let me put my answer this way...
A big problem with using PIC18F2xxx microcontrollers (with K8055-1 board) is their highly limited ability to rearrange inputs and outputs. PIC18FxxJxx (on K8055N-2 boards) are the latest generation of PIC18 microcontrollers and they have an inbuilt PPS (peripheral pin select) unit that gives them almost limitless number of possible relocations of the inputs and outputs of different functional units, including ECCP (enhanced capture, compare and PWM unit). PIC18F2xJ50 firmware from PC USB Projects website allows you to directly access PPS with data memory read and write instructions in PIC18F2xJ50 firmware. You can relocate a functional unit input or output to an arbitrary pin with a single data memory write instruction (e.g.: DataMemWrite(RPINR7, 5) or DataMemWrite(&hEED, 5))… PPS unlocking is already done in PC USB Projects PIC18F2xJ50 firmware, so you don’t have to bother with complex operations. You can also lock PSS again at any time with another DataMemWrite instruction, if you deem necessary to prevent further configuration changes.
A practical example: With a PIC18F2xxx microcontroller on a K8055-1 board you can quickly run into troubles which force you to use software solutions to problems that could be easily solved by using PIC18 functional units (hardware). Let us discuss wireless data transfer. HopeRF RFC wireless communication modules cost just a few euros and they are very easy to use with PIC microcontrollers, if they can be directly connected to a microcontroller input or output. One would prefer to relocate ECCP input to a RA5 (Input 2 in K8055-1 or K8055N-2), but he or she can only do it with a PIC18FxxJxx microcontroller. Trying to use RC1 or RC2 input on PIC18Fxxxx one would have to solder out quite a few resistors on K8055-1 board to lessen the load on the receiver module (RFC83C) output…Alternatively, he or she may try to measure phase length in PIC18Fxxxx firmware (software), but this would be highly inaccurate. PIC18F2xxx CCP also lacks functionality to directly drive certain types of stepper motors (PWM)….
Let me conclude. One can do much more with a PIC18FxxJxx on a K8055N-2 board (or K8055-1 board with an appropriate adapter) than with a PIC18Fxxxx on a modified K8055-1 board… Not to mention that PIC32MX250F128B microcontrollers are far superior to any PIC18 microcontrollers and that PIC18Fxxxx microcontrollers cost almost twice as much as PIC18FxxJxx microcontrollers and approximately the same as PIC32MX250F128B microcontrollers…
ALSO READ:
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- PROGRAMMING GUIDE: PIC32 microcontroller programing in VB.NET