I'm trying to control a ring of addressable LEDs (see datasheet below) by bit banging data using assembly language on a PIC 12f683 as it only accepts data at sub uS speeds, plus it feels like a good learning exercise for my fist time writing assembly!
So far using MikroC I have a function to control one colour on one LED by passing the function a char value.
However now I plan to progress with this code and intend to use the working register to store the data, but when I do so I can see on my oscilloscope the chip always sends the same value 0100 0001 no matter what I send, or even if I set a constant to W reg!
Any reason why this could be? perhaps this value (33/0x22) is an error value?
or perhaps this compare command BTFSS cannot be used with working reg?
any thoughts appreciated
Thanks for your time!
Working code:
Code: Select all
void ringasm(char a){
GPIO.B2 = 0; //set output pin to zero
Delay_us(51); // wait for LED chip to clear
asm {
BSF GPIO+0, 2 //set output to 1
BTFSS FARG_ringasm_a+0, 7 //if bit 7 of char is 1...
BCF GPIO+0, 2 //..skip this clearing of output
BCF GPIO+0, 2 //clear output
NOP //do nothing
BSF GPIO+0, 2 //repeat for bit 6
BTFSS FARG_ringasm_a+0, 6
BCF GPIO+0, 2
BCF GPIO+0, 2
NOP
BSF GPIO+0, 2 //repeat for bit 5
etc...
etc...
etc for all bits to 0th bit...Code: Select all
void ringasm(char a){
GPIO.B2 = 0; //set output pin to zero
Delay_us(51); // wait for LED chip to clear
asm {
CLRW //clear working reg
MOVF FARG_ringasm_a+0, 0 //move char to working reg
BSF GPIO+0, 2 //set output to 1
BTFSS W+0, 7 //if bit 7 of working reg is 1...
BCF GPIO+0, 2 //..skip this clearing of output
BCF GPIO+0, 2 //clear output
NOP //do nothing
BSF GPIO+0, 2 //repeat for bit 6
BTFSS W+0, 6
BCF GPIO+0, 2
BCF GPIO+0, 2
NOP
BSF GPIO+0, 2 //repeat for bit 5 and rest of bits
BTFSS W+0, 5
etc...
etc...https://www.adafruit.com/images/product ... eet%20.pdf
http://akizukidenshi.com/download/ds/mi ... 12f683.pdf
