Soon Kyu Lee's Blog (3)

I faced several problems while working on the PIC to PC communication portion of the programming. Here are some of the major issues with my solutions:

1. Hyperterminal not found.

It seems like Windows 7 does not come with Hyperterminal software. Pretty simple fix: go to the Dropbox link I attached below and download hypertrm.dll and hypertrm.exe. Double clicking hypertrm.exe should start Hyperterminal. If not, try moving these files into C:\Program Files\Windows NT and…

Few things that took me a while to figure out:

1. When using high and low priority interrupts, GIEH must ALSO be enabled along with GIEL (bits 7 and 6) for low priority interrupts to occur.

2. Even when interrupts are not enabled (such as external interrupts on INT0), these are still being flagged. Thus, if there are multiple sources of interrupts and if the interrupt source checking is not handled carefully, disabled interrupt routines may still occur. For example, in my…

Code given in textbook is something like this:

WR_INS

bcf RS ;clear Register Status bit

movwf temp_lcd ;store instruction

andlw 0xF0 ;mask 4 MSB

movwf LATD ;send 4 MSB

bsf E ;pulse enable high

call delay5ms

swapf temp_lcd, 0 ;swap nibbles (result into WREG)

andlw 0xF0 ;mask 4 LSB

bcf E

movwf LATD ;send 4 LSB

bsf E ;pulse enable high

nop

bcf E

call delay5ms ;allow time for change

return

But this does not…