app_ds1631_msg.c¶
ESOS application program to demonstrate I2C mastering in ESOS.
Application recreates code in ds1631_i2c.c in Figure 10.52.
(See Figure 10.49 in the text for circuit.)
Application also has a flashing LED on RB15. Flashing LED is generated by an <em>software timer</em> calling a user-provided callback function.
Note
Demonstrates child tasks, ESOS software timers, and I2C service
- INCLUDEs go here (First include the main esos.h file)
- After that, the user can include what they need
#include "esos.h"
#ifdef __linux
#include "esos_pc.h"
#include "esos_pc_stdio.h"
INCLUDE these so that printf() and our PC hacks work
#include <stdio.h>
#include <sys/select.h>
#include <termios.h>
#include <unistd.h>
#else
#include "esos_pic24.h"
#include "esos_pic24_rs232.h"
#include "esos_pic24_i2c.h"
#include <stdio.h>
#endif
DEFINEs go here
#define DS1631ADDR 0x90 //DS1631 address with all pins tied low
#define ACCESS_CONFIG 0xAC
#define CONFIG_COMMAND 0x0C //continuous conversion, 12-bit mode
#define START_CONVERT 0x51
#define READ_TEMP 0xAA
#ifndef __linux
#if (HARDWARE_PLATFORM == EMBEDDED_F14)
#define CONFIG_LED1() CONFIG_RB15_AS_DIG_OUTPUT()
#define LED1 _LATB15
#else
#define CONFIG_LED1() do{CONFIG_RB15_AS_DIG_OUTPUT();ENABLE_RB15_OPENDRAIN();}while(0)
#define LED1 _LATB15
#endif
#else
#define CONFIG_LED1() printf("called CONFIG_LED1()\n");
uint8_t LED1 = TRUE; // LED1 is initially "on"
#endif
PROTOTYPEs go here
ESOS_USER_TASK( start_ds1631 );
ESOS_USER_TASK( read_ds1631 );
ESOS_USER_TASK( update);
- GLOBALs go here
- Generally, the user-created semaphores will be defined/allocated here
char psz_CRNL[3]= {0x0D, 0x0A, 0};
char psz_prompt[] = "Temp is ";
char psz_done[9]= {' ','D','O','N','E','!',0x0D, 0x0A, 0};
#ifdef __linux
- Simulate the timer ISR found on a MCU
- The PC doesn’t have a timer ISR, so this task will periodically call the timer services callback instead. USED ONLY FOR DEVELOPMENT AND TESTING ON PC. Real MCU hardware doesn’t need this task
ESOS_USER_TASK( __simulated_isr ) {
ESOS_TASK_BEGIN();
while (TRUE) {
call the ESOS timer services callback just like a real H/W ISR would
__esos_tmrSvcsExecute();
ESOS_TASK_WAIT_TICKS( 1 );
} // endof while(TRUE)
ESOS_TASK_END();
} // end child_task
#endif
/************************************************************************
* User supplied functions
************************************************************************
*/
An ESOS software timer callback function strobe the heartbeat LED.
Toggles LED1 everytime the callback is called. Exact period is determined by application when this timer callback function is registered with ESOS. See ref esos_RegisterTimer Application can change timer period on-the-fly with ref esos_ChangeTimerPeriod
note Since this heartbeat is performed in an ESOS software timer callabck, a flashing LED indicates that the ESOS system tick ISR is being called properly. If the LED quits flashing, then the ESOS system tick has ceased working. This probably indicates some catastrophic failure of the system. However, the cause could be poorly-behaved user code that is manipulating the hardware registers with the timer or interrupt enables directly. ESOS provides functions to change state of interrupts and user code should never modify the hardware used by ESOS to implement the system tick. hideinitializer
user-created timer callback
ESOS_USER_TIMER( swTimerLED ) {
LED1 = !LED1;
#ifdef __linux
if (LED1) {
printf("\a");
fflush(stdout);
}
#endif
} //endof swTimerLED
user task to setup DS1631 for continuous temperature conversion. Will signal when DS1631 is ready to be used.
ESOS_USER_TASK(start_ds1631) {
static ESOS_TASK_HANDLE hTask;
static MAILMESSAGE st_Message;
ESOS_TASK_BEGIN();
ESOS_TASK_WAIT_TICKS(500);
ESOS_TASK_WAIT_ON_AVAILABLE_I2C();
ESOS_TASK_WAIT_ON_WRITE2I2C1(DS1631ADDR, ACCESS_CONFIG, CONFIG_COMMAND);
ESOS_TASK_WAIT_ON_WRITE1I2C1(DS1631ADDR, START_CONVERT);
ESOS_TASK_SIGNAL_AVAILABLE_I2C();
ESOS_TASK_WAIT_TICKS(500);
send a mail message to read_ds1631. receipt of this message will “signal” that the DS1631 is configured and ready to be used.
hTask = esos_GetTaskHandle( read_ds1631 );
ESOS_TASK_MAKE_MSG_EMPTY(st_Message); // create message locally
ESOS_TASK_WAIT_ON_TASKS_MAILBOX_HAS_AT_LEAST(hTask, 0); // wait until recipient has mailbox space
ESOS_TASK_SEND_MESSAGE(hTask, &st_Message);
ESOS_TASK_END();
} //end task start_ds1631
user task to read DS1631 every 3/4 second will signal when data has been successfully read
ESOS_USER_TASK(read_ds1631) {
static uint8_t u8_lo, u8_hi;
static MAILMESSAGE st_Msg;
static ESOS_TASK_HANDLE h_TaskUpdate;
ESOS_TASK_BEGIN();
wait for mail. The first message will be from task start_ds1631 and will notify us that the DS1631 is configured and ready to go
ESOS_TASK_WAIT_FOR_MAIL();
We got (at least) one message, so DS1631 is ready to go. Contents of message are not important
ESOS_TASK_GET_LAST_MESSAGE( &st_Msg);
h_TaskUpdate = esos_GetTaskHandle( update );
while (TRUE) {
ESOS_TASK_WAIT_ON_AVAILABLE_I2C();
ESOS_TASK_WAIT_ON_WRITE1I2C1(DS1631ADDR, READ_TEMP);
ESOS_TASK_WAIT_ON_READ2I2C1(DS1631ADDR, u8_hi, u8_lo);
ESOS_TASK_SIGNAL_AVAILABLE_I2C();
send a mail message to update. When update receives the message, we know that the display is updating the display
ESOS_TASK_MAKE_MSG_UINT8_X2(st_Msg, u8_hi, u8_lo); // create message locally
ESOS_TASK_WAIT_ON_TASKS_MAILBOX_HAS_AT_LEAST(h_TaskUpdate, 2*sizeof(uint8_t)); // wait until recipient has mailbox space
ESOS_TASK_WAIT_ON_DELIVERY(h_TaskUpdate, &st_Msg);
wait 3/4 second after screen updates before sending another temperature reading
ESOS_TASK_WAIT_TICKS(750);
} //end while()
ESOS_TASK_END();
} //end task read_ds1631
User task to display temperature results from DS1631. Used printf and floating point for convenience. A production application would likely create custom functions to avoid including these huge libraries.
ESOS_USER_TASK(update) {
float f_tempC, f_tempF;
static MAILMESSAGE st_Msg;
int16_t i16_temp;
ESOS_TASK_BEGIN();
while (TRUE) {
wait for mail. We only get mail from read_ds1631 so we will NOT decipher which task sent the message. In practice, a task should verify that mail comes from the expected task.
ESOS_TASK_WAIT_FOR_MAIL();
- get the “newest” mail message, flushing the rest.
- this is the most recent DS1631 reading
ESOS_TASK_GET_LAST_MESSAGE( &st_Msg);
i16_temp = st_Msg.au8_Contents[0]; // u8_hi
i16_temp = ((i16_temp<<8)|st_Msg.au8_Contents[1]); // u8_lo
f_tempC = (float) i16_temp; //convert to floating point
f_tempC = f_tempC/256; //divide by precision
f_tempF = f_tempC*9/5 + 32;
printf("MSG Temp is: 0x%0X, %4.4f (C), %4.4f (F)\n", i16_temp, (double) f_tempC, (double) f_tempF);
} // end while(TRUE)
ESOS_TASK_END();
} // end update()
/****************************************************
* user_init()
****************************************************
*/
void user_init(void) {
#ifdef __linux
register our little ESOS task to mimic MCU’s TIMER T1 IRQ which kicks off the ESOS S/W timers when they expire
esos_RegisterTask( __simulated_isr );
#endif
configure our hardware to support to support our application
CONFIG_LED1();
esos_pic24_configI2C1(400); //configure I2C for 400 Kbps
user_init() should register at least one user task
esos_RegisterTask(start_ds1631);
esos_RegisterTask(read_ds1631);
esos_RegisterTask(update);
register our callback function with ESOS to create a software timer
esos_RegisterTimer( swTimerLED, 250);
Call the hardware-provided routines to print the HELLO_MSG to the screen. Must use this call because the ESOS communications subsystems is not yet fully initialized, since this call is in user_init()
In general, users should call hardware-specific function like this.
__esos_unsafe_PutString( HELLO_MSG );
} // end user_init()