-- Title: Program to test an i2c bus (using i2c hardware slave)
-- Author: Sebastien Lelong, Copyright (c) 2008-2009, all rights reserved.
-- Adapted-by: 
-- Compiler: >=2.4m
-- Revision: $Revision$
--
-- This file is part of jallib  (http://jallib.googlecode.com)
-- Released under the BSD license (http://www.opensource.org/licenses/bsd-license.php)
--
-- Description: this is a one shot test program. It's used to check if
-- i2c bus is properly operational. It requires an SSP/i2c enabled PIC
-- --
-- The idea is enable Start/Stop interrupts. When master sends something, whatever
-- the address, it should produce an interrupt on this slave. As soon as interrupt
-- is dealt with, a LED is flashing indefinitely (it also slowly blink when PIC is up)
--
-- Sources:
--
--
-- This file has been generated by jallib.py from:
--    * board: board_16f88_js.jal
--    * test : test_i2c_hw_slave_check_bus.jal
--

;@jallib section chipdef
-- chip setup
include 16f88

;--
;-- This setup assumes a 20 MHz resonator or crystal
;-- is connected to pins OSC1 and OSC2.
pragma target OSC       HS             -- HS crystal or resonator
pragma target clock     20_000_000     -- oscillator frequency
pragma target WDT       disabled       -- no watchdog
pragma target LVP       disabled       -- no low-voltage programming
pragma target CCP1MUX   pin_B3         -- ccp1 pin on B3

--
-- This setup uses the internal oscillator
;pragma target OSC       INTOSC_NOCLKOUT   -- HS crystal or resonator
;pragma target clock     8_000_000         -- oscillator frequency
;pragma target WDT       disabled          -- no watchdog
;pragma target LVP       disabled          -- no low-voltage programming
;pragma target CCP1MUX   pin_B3            -- ccp1 pin on B3
;OSCCON_IRCF = 7                           -- set prescaler to 1 (8 MHz)

enable_digital_io()
;@jallib section led
-- LED IO definition
alias led             is pin_b3
alias led_direction   is pin_b3_direction
alias led2            is pin_b1
alias led2_direction  is pin_b1_direction

-- i2c setup
-- with Start/Stop interrupts
const bit i2c_enable_start_stop_interrupts = true
include i2c_hw_slave
const SLAVE_ADDRESS = 0x23 -- whatever, it's not important, and can be
						   -- different from the address the master wants
						   -- to talk to
-- this init automatically sets global/peripherals interrupts
i2c_hw_slave_init(SLAVE_ADDRESS)


-- Main ISR
procedure i2c_isr() is
   pragma interrupt
   if ! PIR1_SSPIF then
      return
   end if
   -- reset flag  
   PIR1_SSPIF = false
   -- tmp store SSPSTAT and mask out unimportant bit
   var byte tmpstat
   tmpstat = SSPSTAT
   -- check start signals
   if (tmpstat == 0b_1000) then
	  -- If we get there, this means this is an SSP/I2C interrupts
   	  -- and this means i2c bus is properly operational !!!
   	  while true loop
   	     led = on
   	     _usec_delay(100000)
   	     led = off
   	     _usec_delay(100000)
   	  end loop
   end if
end procedure

-- Blink a little when PIC is up
led_direction = output
for 4 loop
   led = on
   _usec_delay(250000)
   led = off
   _usec_delay(250000)
end loop

-- waiting for interrupts
forever loop
end loop