I can't find any tutorials specific to PIC18F4550 using MPASM.
; PIC18F4550 Configuration Bit Settings
; Assembly source line config statements
#include "p18f4550.inc"
; CONFIG1L
CONFIG PLLDIV = 1 ; PLL Prescaler Selection bits (No prescale (4 MHz oscillator input drives PLL directly))
CONFIG CPUDIV = OSC1_PLL2 ; System Clock Postscaler Selection bits ([Primary Oscillator Src: /1][96 MHz PLL Src: /2])
CONFIG USBDIV = 1 ; USB Clock Selection bit (used in Full-Speed USB mode only; UCFG:FSEN = 1) (USB clock source comes directly from the primary oscillator block with no postscale)
; CONFIG1H
CONFIG FOSC = INTOSC_XT ; Oscillator Selection bits (Internal oscillator, XT used by USB (INTXT))
CONFIG FCMEN = OFF ; Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor disabled)
CONFIG IESO = OFF ; Internal/External Oscillator Switchover bit (Oscillator Switchover mode disabled)
; CONFIG2L
CONFIG PWRT = OFF ; Power-up Timer Enable bit (PWRT disabled)
CONFIG BOR = ON ; Brown-out Reset Enable bits (Brown-out Reset enabled in hardware only (SBOREN is disabled))
CONFIG BORV = 3 ; Brown-out Reset Voltage bits (Minimum setting 2.05V)
CONFIG VREGEN = OFF ; USB Voltage Regulator Enable bit (USB voltage regulator disabled)
; CONFIG2H
CONFIG WDT = ON ; Watchdog Timer Enable bit (WDT enabled)
CONFIG WDTPS = 32768 ; Watchdog Timer Postscale Select bits (1:32768)
; CONFIG3H
CONFIG CCP2MX = ON ; CCP2 MUX bit (CCP2 input/output is multiplexed with RC1)
CONFIG PBADEN = ON ; PORTB A/D Enable bit (PORTB<4:0> pins are configured as analog input channels on Reset)
CONFIG LPT1OSC = OFF ; Low-Power Timer 1 Oscillator Enable bit (Timer1 configured for higher power operation)
CONFIG MCLRE = ON ; MCLR Pin Enable bit (MCLR pin enabled; RE3 input pin disabled)
; CONFIG4L
CONFIG STVREN = ON ; Stack Full/Underflow Reset Enable bit (Stack full/underflow will cause Reset)
CONFIG LVP = ON ; Single-Supply ICSP Enable bit (Single-Supply ICSP enabled)
CONFIG ICPRT = OFF ; Dedicated In-Circuit Debug/Programming Port (ICPORT) Enable bit (ICPORT disabled)
CONFIG XINST = OFF ; Extended Instruction Set Enable bit (Instruction set extension and Indexed Addressing mode disabled (Legacy mode))
; CONFIG5L
CONFIG CP0 = OFF ; Code Protection bit (Block 0 (000800-001FFFh) is not code-protected)
CONFIG CP1 = OFF ; Code Protection bit (Block 1 (002000-003FFFh) is not code-protected)
CONFIG CP2 = OFF ; Code Protection bit (Block 2 (004000-005FFFh) is not code-protected)
CONFIG CP3 = OFF ; Code Protection bit (Block 3 (006000-007FFFh) is not code-protected)
; CONFIG5H
CONFIG CPB = OFF ; Boot Block Code Protection bit (Boot block (000000-0007FFh) is not code-protected)
CONFIG CPD = OFF ; Data EEPROM Code Protection bit (Data EEPROM is not code-protected)
; CONFIG6L
CONFIG WRT0 = OFF ; Write Protection bit (Block 0 (000800-001FFFh) is not write-protected)
CONFIG WRT1 = OFF ; Write Protection bit (Block 1 (002000-003FFFh) is not write-protected)
CONFIG WRT2 = OFF ; Write Protection bit (Block 2 (004000-005FFFh) is not write-protected)
CONFIG WRT3 = OFF ; Write Protection bit (Block 3 (006000-007FFFh) is not write-protected)
; CONFIG6H
CONFIG WRTC = OFF ; Configuration Register Write Protection bit (Configuration registers (300000-3000FFh) are not write-protected)
CONFIG WRTB = OFF ; Boot Block Write Protection bit (Boot block (000000-0007FFh) is not write-protected)
CONFIG WRTD = OFF ; Data EEPROM Write Protection bit (Data EEPROM is not write-protected)
; CONFIG7L
CONFIG EBTR0 = OFF ; Table Read Protection bit (Block 0 (000800-001FFFh) is not protected from table reads executed in other blocks)
CONFIG EBTR1 = OFF ; Table Read Protection bit (Block 1 (002000-003FFFh) is not protected from table reads executed in other blocks)
CONFIG EBTR2 = OFF ; Table Read Protection bit (Block 2 (004000-005FFFh) is not protected from table reads executed in other blocks)
CONFIG EBTR3 = OFF ; Table Read Protection bit (Block 3 (006000-007FFFh) is not protected from table reads executed in other blocks)
; CONFIG7H
CONFIG EBTRB = OFF ; Boot Block Table Read Protection bit (Boot block (000000-0007FFh) is not protected from table reads executed in other blocks)
; __CONFIG _WDT_OFF & _CP_OFF & _MCLRE_OFF
ORG 0x0000
INIT ; We are initializing the microcontroller over the next three lines.
MOVLW ~(1 << TRISA0) ;these two lines set GP1 as an output
MOVWF TRISA
BSF TRISA, TRISA0 ;this line is where we set GP1 output high to light the LED
LOOP
GOTO LOOP ; loop forever
END ; Needed to end the program.
I've copied the main code from this tutorial, https://www.circuitbread.com/tutorials/the-first-assembly-program-part-5-simple-microcontroller-pic10f200. It builds fine but I get The following:
memory area(s) will be programmed:
program memory: start address = 0x0, end address = 0x7f
configuration memory
program memory
Address: 0 Expected Value: fe Received Value: 0
Failed to program device
I suspect my syntax is wrong somehow, or am I doing something wrong completely. The data sheet is too technical for me to understand. Logic should be, move literal into working register, move working register to file register trisa, set bit to high so it outputs?
After looking at code I know works and rereading the data sheet I think I understand now. I believe I've been using BSF wrong, it's BSF TRISA, 1 I think rather than BSF TRISA, TRISA1. And I should be using Data Latch Register
BSF Bit Set f
Syntax: BSF f, b {,a}
Operands: 0 ≤ f ≤ 255
0 ≤ b ≤ 7
a ∈ [0,1]
Operation: 1 → f<b>
Status Affected: None
Encoding: 1000 bbba ffff ffff
Description: Bit ‘b’ in register ‘f’ is set.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 26.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write
register ‘f’
Example: BSF FLAG_REG, 7, 1
Before Instruction
FLAG_REG = 0Ah
After Instruction
FLAG_REG = 8Ah`
`CLRF PORTD ; Initialize PORTD by
; clearing output
; data latches
CLRF LATD ; Alternate method
; to clear output
; data latches
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISD ; Set RD<3:0> as inputs
; RD<5:4> as outputs
; RD<7:6> as inputs`
`CLRF PORTA ; Initialize PORTA by
; clearing output
; data latches
CLRF LATA ; Alternate method
; to clear output
; data latches
MOVLW 0Fh ; Configure A/D
MOVWF ADCON1 ; for digital inputs
MOVLW 07h ; Configure comparators
MOVWF CMCON ; for digital input
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISA ; Set RA<3:0> as inputs
; RA<5:4> as outputs`