Microchip Devices

Detailed Device compaisons and selection aids.

When selecting a device to use for development, keep in mind that code for the smaller devices can often be written more easily and faster using the larger devices, since you can take advantage of the extra space and ability for debug routines, self test hardware and, with the 16f877 and higher chips, the low cost and more accurate debugging abilities of the ICD

jamesp at intertex.net says:

Just as an FYI, you can use the ICD to develop software for ANY downward level PIC by just using those peripheral modules that your target PIC is equipped with. For instance, I have used the ICD to develop code for the 16F877, 16F84, 16C84, 16C71, 12C672, and the 12C508. In all but one instance, the code developed for these parts worked first time out in the target. The one time it didn't is because I screwed up and put some code where there wasn't any memory in the target. But once I changed that, all went well. So, bottom line is the ICD can be used to develop code for anything from the F877 on down.

Device specific notes:

• PIC10Fxxx: are the smallest microcontrollers available from anyone: tiny 6 pin packages. (They all use the "12 bit core", right?)
  • Make you own adapter for the 10Fxxx PICs

  PIC12xxx: the PIC12 Family of Microcontrollers are very small 8 pin packages. This family includes some of the lowest-cost microcontrollers available (under $2 in ones). (The Atmel ATtiny and Freescale S08 series also include 8 pin microcontrollers for under $2 -- are there any others?) A few PIC12 use the "12 bit core", the rest use the "14 bit core".

  • FSR pointer: Handeling shared and paged register references
  • Inc and Dec W without changing other registers
  • 12C5xx OSCAL
  • "Use a PIC16C84 to develop a $5 emulator for a PIC12C508 Isn't worth $5. Is there is a code library that fills in the gaps?
  • see also:
    • http://quozl.us.netrek.org/porting-16f84-12c509/ Checklist for Porting (12-bit core) 16f84 code to the (12-bit core) 12c509
    • http://www.findarticles.com/m3161/16_48/64493919/p1/article.jhtml How to emulate the MM53200 with a PIC12C508
• 16xxx 16C5X Instruction set. The PIC16 Family of Microcontrollers. With the exception of the (probably mis-named, but too late to change now) PIC16C5X and PIC16F5X which have a "12 bit core", the PIC16 series of chips all have a "14 bit core".
  • It is difficult, but not impossible, to get a multitasking system running on a 14-bit core.
  • A PC-Based Development Programmer for the PIC16C84 Two chips, three transistors, some RC components and the 84 is programmable!
  • Using SRAM With A PIC16CXXX two glue and two static ram chips yeilds about 64k at a cost of 19i/o pins and is functional with any 40 pin member of the 16Cxx family. Subroutines used to read and write
  • Onboard UARTS, Thomas C. Sefranek's 16C73 USART Serial Port Gotcha List and Source
  • Memory Paging
  • The difference between 16C63 - 16C63A is that they made a new, smaller die and if you look carefully in the datasheet, there are two bugs in the silicon that are fixed -- one with GIE, and the other with the high speed asynchronous mode of the USART.
• 16f87x
  • http://www.wsu.edu/~jackdoll/jmon/ A useful little monitor program for the '877 from Jack Dollhausen
  • Can't re-program chip after code protecting the data eeprom
  • Can't program 16f8xx in traditional high voltage programmer?
  • Programming modes
  • Reading program memory, interrupt jitter, simulator error
  • Fashing LED program for 16f877
  • A/D sample programs for 16f877 and 16f873
  • Minimal setup program for 16F877
  • Setting up a 16F87x for PWM output
  • USART, I2C, EERAM read/write, port setup, ISR, and full initialization sample from Tony Kübek of Flintab AB [tony.kubek at flintab.com]
  • Internal EEPROM access on the 16F874/16F877
  • The EBB/CUMP/serial ICD idea
  • PIC 16F876A based Temperature (DS1620) / Humidity (HS15p) Display (Hitachi LCD) by Jody Wisman
• 17xxx Instruction set PIC17 MCU Family Product Overview are now obsolete -- they have been replaced by the PIC18 family.
  • Using External RAM with PIC17CXX Devices Two glue, two static ram chips yelds about 64k with 14i/o pins remaining. Single instructions read and write. (Microchip TB005).
  • In Circuit Serial Programming the 17C766 by Dave Roberts
  • Seperating the Vcc and Gnd for the A/D converter
• PIC18xxx: Microchip PIC18 Microcontrollers all have a "16 bit core". (But they are 8 bit CPUs just like the previous).
  • PIC18xxx instruction set
  • Instruction differences between the 16 bit core and the 14 bit core
  • Exception handling
  • Function pointers (like in "C")
  • Multilevel returns
  • Unlimited computed goto (or table lookup)
  • Tables on the 18C
  • Also: Multitasking / Context Switching@
• dsPIC
  • dsPIC30F2010 proto board by Leon F Heller of LFH Associates

Microcontroller "Conversion Guidelines" and "Migration Documents" (such as "PIC18F to PIC24F Migration: An Overview" ) are helpful when you have source code designed for one chip, but you want it to run on a different chip. There are many reasons for people to do this:

• you want to go to mass production, and the new chip is less expensive
• You want to continue production, but the old chip is no longer available at any price
• You want to add features that the old chip can't handle -- you need it to run faster, or you need a USB interface, or you want to add other features that require more RAM or more FLASH than the old chip could handle.

In addition to microcontrollers, Microchip also sells many other ICs:

• external analog to digital converters (can sample faster and at higher resolution than any built-in ADC in any microcontroller)
• 24AA256 - 32kx8 Serial I2C EEPROM
• 24C64
• 24C16

Questions:

• Mohd Iskandar Bin Mohd Saleh of Personal asks:

  i'm looking for the example of source code to using USART asynchronous to communicate with GSM module/GSM modem by AT command...i'm already start the development of this project since 2 month ago according to PIC 877 data sheet...but i'm still cannot send my first sms...please email me at iskandarsaleh@gmail.com if anybody can help me...

• schmitz at akula.com asks: " What is the difference between the 16C73A and 16C73B? What makes the A version more expensive?"

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