JAL manual - library : jpic

The following special function registers are declared:

   var volatile byte indf   at  0
   var volatile byte tmr0   at  1
   var volatile byte pcl    at  2
   var volatile byte status at  3
   var volatile byte fsr    at  4
   var volatile byte porta  at  5
   var volatile byte portb  at  6
   var volatile byte portc  at  6
   var volatile byte eedata at  8
   var volatile byte eeadr  at  9
   var volatile byte pclath at 10
   var volatile byte intcon at 11
   var volatile byte option
   var volatile byte trisa
   var volatile byte trisb
   var volatile byte trisc

The option variable is a pseudo-variable maintained by small routines. The porta .. portc and trisa ... trisc variables are explained in the next section.

The following bits are declared within the special function registers:

   var volatile bit  status_c    at status : 0
   var volatile bit  status_dc   at status : 1
   var volatile bit  status_z    at status : 2
   var volatile bit  status_pd   at status : 3
   var volatile bit  status_to   at status : 4
   var volatile bit  status_rp0  at status : 5
   var volatile bit  status_rp1  at status : 6
   var volatile bit  status_irp  at status : 7

   var volatile bit  intcon_rbif at intcon : 0
   var volatile bit  intcon_intf at intcon : 1
   var volatile bit  intcon_t0if at intcon : 2
   var volatile bit  intcon_rbie at intcon : 3
   var volatile bit  intcon_inte at intcon : 4
   var volatile bit  intcon_t0ie at intcon : 5
   var volatile bit  intcon_eeie at intcon : 6
   var volatile bit  intcon_gie  at intcon : 7

• port_a_direction, port_b_direction, port_c_direction (bytes)
• port_a_low_direction, port_a_high_direction, port_b_low_direction, port_b_high_direction, port_c_low_direction, port_c_high_direction (nibbles)
• pin_a0_direction .. pin_a4_direction, pin_b0_direction .. pin_b7_direction, pin_c0_direction .. pin_c7_direction (bits)

At startup all pins are inputs.

The following constants should be used to change directions:

• input, output (for bits)
• all_input, all_output (for nibbles and bytes)

For the half-port (nibble) variables the direction is according to the lower 4 bits. The higher 4 bits are ignored and read as 0.

The following pseudo-variables are provided which can be used either to the right or to the left of an assignment statement:

• port_a, port_b, port_c (bytes)
• port_a_low, port_a_high, port_b_low, port_b_high, port_c_low, port_c_high (nibbles)
• pin_a0 .. pin_a4 pin_b0 .. pin_b7, pin_c0 .. pin_c7 (bits)

For the half-port (nibble) variables the value is according to the lower 4 bits. The higher 4 bits are ignored and read as 0.

The following routines are provided to get and put data at a specified file register:

   procedure file_get( byte in a, byte out d )
   procedure file_put( byte in a, byte in d )

The address passed to the file_get and file_put routines must be a linear address. The linear file register addresses are consequtive and non-overlapping.

The following routines are provided to get and put data at a specified data eeprom address:

   procedure eeprom_get( byte in a, byte out d )
   procedure eeprom_put( byte in a, byte in d )

The eeprom_put routine waits (busy looping) for the write to complete.

   procedure sleep

   procedure clear_watchdog

   procedure swap_nibbles( byte in out x ) 

   procedure page_0
   procedure page_1