MPASM Toolchain

__config

The directive __config is used for PIC10/12/16 MCUs. It may be used for PIC18 MCUs (excluding PIC18FXXJ devices) but the config directive is recommended. The syntax is as follows:

__config expr        ;For a single configuration word

__config addr, expr  ;For multiple configuration word

where:

`addr`	Address of the Configuration Word. May be literal but usually represented by a macro. Note: Macros must be listed in ascending register order.
`expr`	Expression representing the value to which the specified Configuration bits will be set. May be literal but usually represented by a macro or macros ANDed together.

Macros are specified in the device include file (*.inc) that is located in the Windows operating system (OS) default directory:

C:\Program Files\Microchip\MPLABX\mpasmx

Directive case does not matter; __CONFIG or __config is acceptable. Macro case should match what is in the header.

In the “MPASM Assembler, MPLINK Object Linker, MPLIB Object Librarian User’s Guide” (DS30003014), see “__config - Set Processor Configuration Bits.”

Example – PIC10/12/16 MCUs

#include p16f877a.inc
;Set oscillator to HS, watchdog time off, low-voltage prog. off
__CONFIG _HS_OSC & _WDT_OFF & _LVP_OFF

Example – PIC18 MCUs

#include p18f452.inc
;Oscillator switch enabled, RC oscillator with OSC2 as I/O pin.
__CONFIG    _CONFIG1, _OSCS_OFF_1 & _RCIO_OSC_1
;Watch Dog Timer enable, Watch Dog Timer PostScaler count - 1:128
__CONFIG    _CONFIG3, _WDT_ON_3 & _WDTPS_128_3

config

The directive config is used for PIC18 MCUs (including PIC18FXXJ devices). The syntax is as follows:

config setting=value [, setting=value]

where:

`setting`	Macro representing a Configuration bit or bits.
`value`	Macro representing the value to which the specified Configuration bit(s) will be set. Multiple settings may be defined on a single line, separated by commas. Settings for a single configuration byte may also be defined on separate lines.

Macros are specified in the device include file (*.inc) that is located in the Windows OS default directory:

C:\Program Files\Microchip\MPLABX\mpasmx

Directive case does not matter; __CONFIG or __config is acceptable. Macro case should match what is in the header.

In the “MPASM Assembler, MPLINK Object Linker, MPLIB Object Librarian User’s Guide” (DS30003014), see “config - Set Processor Configuration Bits (PIC18 MCUs).”

Example – PIC18 MCUs

#include p18f452.inc
;Oscillator switch enabled, RC oscillator with OSC2 as I/O pin.
CONFIG     OSCS=ON, OSC=LP
;Watch Dog Timer enable, Watch Dog Timer PostScaler count - 1:128
CONFIG     WDT=ON, WDTPS=128