Myke Predko says:
When I was doing the second edition of my PICmicro microcontroller book, I did some hacking of the ICD Interface and I found that in "ICD mode", all the hardware registers could be written to, but any changes to them didn't take effect until *after* a "return" instruction was executed.
While the PICmicro MCU was in ICD mode the only hardware resources that could be accessed correctly were:
- RB6/RB7 via 0x0106. Only the Programming "Data" pin's TRIS bit could be changed. The Clock bit stayed in input mode.
- Program memory flash read/write controls.
- ICKBUG and BIGBUG (according to DS51242A - I didn't have this document when I was playing around with it so I called the registers "Reserve_E" and "Reserve_F") could be read and written before executing a "return" to return to the executing application.
- STATUS, PCLATH, FSR
- All File Registers
If you are interested in seeing what I found, Take a look at pages 650 to 652 of the book. On the CD-ROM, in the EMU-II directory, you will find the source code that I created from the 256 instructions inserted into the ICD by the controller.
|file: /Techref/microchip/icdhow.htm, 2KB, , updated: 2008/4/10 15:56, local time: 2022/12/1 16:35,
|©2022 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?|
<A HREF="http://techref.massmind.org/Techref/microchip/icdhow.htm"> How the Microchip ICD Works</A>
|Did you find what you needed?|
Welcome to massmind.org!
Welcome to techref.massmind.org!