/*
* Copyright (c) 2010, Loughborough University - Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*/
/**
* \file
* This file provides functions to control various chips on the
* Sensinode N740s:
*
* - The 74HC595D is an 8-bit serial in-parallel out shift register.
* LEDs are connected to this chip. It also serves other functions such as
* enabling/disabling the Accelerometer (see n740.h).
* - The 74HC4053D is a triple, 2-channel analog mux/de-mux.
* It switches I/O between the USB and the D-Connector.
* It also controls P0_0 input source (Light Sensor / External I/O)
*
* Mux/De-mux: Connected to P0_3 (set to output in models.c
* Changing the state of the mux/demux can have catastrophic (tm) results
* on our software. If we are not careful, we risk entering a state where
* UART1 RX interrupts are being generated non-stop. Only change its state
* via the function in this file.
*
* Shift Register:
* For the shift register we can:
* - write a new instruction
* - remember and retrieve the last instruction sent
*
* The chip is connected to CPU pins as follows:
* - P0_2: Serial Data Input
* - P1_3: Shift Register Clock Input
* - P1_1: Storage Register Clock
*
* This file can be placed in any bank.
*
* \author
* George Oikonomou - <oikonomou@users.sourceforge.net>
*/
#include "dev/n740.h"
#include "dev/uart1.h"
#include "8051def.h"
/*
* This variable stores the most recent instruction sent to the ser-par chip.
* We declare it as static and return its value through n740_ser_par_get().
*/
static CC_AT_DATA uint8_t ser_par_status;
/*---------------------------------------------------------------------------*/
/* Init the serial-parallel chip:
* - Set I/O direction for all 3 pins (P0_2, P1_1 and P1_3) to output
*/
void
n740_ser_par_init()
{
/* bus_init and uart1_init also touch the I/O direction for those pins */
P1DIR |= 0x0A;
P0DIR |= 0x04;
}
/*---------------------------------------------------------------------------*/
/*
* Send a command to the N740 serial-parallel chip. Each command is a single
* byte, each bit controls a different feature on the sensor.
*/
void
n740_ser_par_set(uint8_t data)
{
uint8_t i;
uint8_t mask = 1;
uint8_t temp = 0;
DISABLE_INTERRUPTS();
/* bit-by-bit */
for(i = 0; i < 8; i++) {
temp = (data & mask);
/* Is the bit set? */
if(i && temp) {
/* If it was set, we want to send 1 */
temp >>= i;
}
/* Send the bit */
P0_2 = temp;
/* Shift */
P1_3 = 1;
P1_3 = 0;
mask <<= 1;
}
/* Move to Par-Out */
P1_1 = 1;
P1_1 = 0;
ENABLE_INTERRUPTS();
/* Right, we're done. Save the new status in ser_par_status */
ser_par_status = data;
}
/*---------------------------------------------------------------------------*/
/* This function returns the last value sent to the ser-par chip on the N740.
*
* The caveat here is that we must always use n740_set_ser_par() to send
* commands to the ser-par chip, never write directly.
*
* If any other function sends a command directly, ser_par_status and the
* actual status will end up out of sync.
*/
uint8_t
n740_ser_par_get()
{
return ser_par_status;
}
/*---------------------------------------------------------------------------*/
void
n740_analog_switch(uint8_t state)
{
/* Turn off the UART RX interrupt before switching */
DISABLE_INTERRUPTS();
UART1_RX_INT(0);
/* Switch */
P0_3 = state;
/* If P0_3 now points to the USB and nothing is flowing down P1_7,
* enable the interrupt again */
if(P1_7 == 1 && P0_3 == N740_ANALOG_SWITCH_USB) {
UART1_RX_INT(1);
}
ENABLE_INTERRUPTS();
}
/*---------------------------------------------------------------------------*/
/*
* Activate the the 74HC4053D analog switch U5 on the N740 and at the same
* time set relevant pins to Peripheral I/O mode. This stops communications
* with the serial flash and enables UART1 I/O
*/
void
n740_analog_activate()
{
uint8_t ser_par = n740_ser_par_get();
ser_par &= ~N740_SER_PAR_U5_ENABLE; /* Turn on */
N740_PINS_PER_IO();
n740_ser_par_set(ser_par);
}
/*---------------------------------------------------------------------------*/
/*
* De-Activate the the 74HC4053D analog switch U5 on the N740 and at the same
* time set relevant pins to GP I/O mode. This effectively prepares us to
* start talking with the serial flash chip
*/
void
n740_analog_deactivate()
{
uint8_t ser_par = n740_ser_par_get();
ser_par |= N740_SER_PAR_U5_ENABLE; /* Turn off */
n740_ser_par_set(ser_par);
N740_PINS_GPIO();
}
/*---------------------------------------------------------------------------*/