?? f31x_adc0_externalinput.lst
字號(hào):
220 1 Timer2_Init(); // Init Timer2 to generate
221 1 // overflows to trigger ADC
222 1 UART0_Init(); // Initialize UART0 for printf's
223 1 ADC0_Init(); // Initialize ADC0
224 1
225 1 EA = 1; // enable global interrupts
226 1 while (1) { // spin forever
227 2 ADC_Read_Ch(0x0C);
228 2 }
229 1 }
230
231 //-----------------------------------------------------------------------------
232 // Initialization Subroutines
233 //-----------------------------------------------------------------------------
234 //
235 //-----------------------------------------------------------------------------
236 // SYSCLK_Init
237 //-----------------------------------------------------------------------------
238 //
239 // Return Value: None
240 // Parameters: None
241 //
C51 COMPILER V8.08 F31X_ADC0_EXTERNALINPUT 03/20/2009 15:55:34 PAGE 5
242 // This routine initializes the system clock to use the internal 24.5MHz
243 // oscillator as its clock source. Also enables missing clock detector reset.
244 //
245 //-----------------------------------------------------------------------------
246
247 void SYSCLK_Init (void)
248 {
249 1 OSCICN = 0x83; // configure internal oscillator for
250 1 // 24.5MHz / 1
251 1 RSTSRC = 0x04; // enable missing clock detector
252 1 }
253
254 //-----------------------------------------------------------------------------
255 // PORT_Init
256 //-----------------------------------------------------------------------------
257 //
258 // Return Value: None
259 // Parameters: None
260 //
261 // Configure the Crossbar and GPIO ports.
262 // P0.0 - VREF input / output
263 // P0.4 - UART TX (push-pull)
264 // P0.5 - UART RX
265 // P2.5 - ADC0 analog input
266 // P3.3 - LED (push-pull)
267 //
268 //-----------------------------------------------------------------------------
269
270 void PORT_Init (void)
271 {
272 1 XBR0 = 0x01; // Enable UART0
273 1 XBR1 = 0x40; // Enable crossbar and weak pull-ups
274 1 P0MDOUT |= 0x11; // Set P0.1, TX pins to push-pull
275 1 P0SKIP = 0x01; // force crossbar to skip P0.0
276 1 P3MDOUT |= 0x08; // enable LED as a push-pull output
277 1 P2MDIN &= ~0x20; // set P2.5 as an analog input
278 1 P3MDIN = 0xFF;
279 1 P0 = 0x01; // drive P0.0 high to provide Vdd at
280 1 // header for external voltage divider
281 1 }
282
283 //-----------------------------------------------------------------------------
284 // Timer2_Init
285 //-----------------------------------------------------------------------------
286 //
287 // Return Value: None
288 // Parameters: None
289 //
290 // Configure Timer2 to 16-bit auto-reload and generate an interrupt at 100uS
291 // intervals. Timer 2 overflow automatically triggers ADC0 conversion.
292 //
293 //-----------------------------------------------------------------------------
294
295 void Timer2_Init (void)
296 {
297 1 TMR2CN = 0x00; // Stop Timer2; Clear TF2;
298 1 // use SYSCLK as timebase, 16-bit
299 1 // auto-reload
300 1 CKCON |= 0x10; // select SYSCLK for timer 2 source
301 1 TMR2RL = 65535 - (SYSCLK / 10000); // init reload value for 10uS
302 1 TMR2 = 0xffff; // set to reload immediately
303 1 TR2 = 1; // start Timer2
C51 COMPILER V8.08 F31X_ADC0_EXTERNALINPUT 03/20/2009 15:55:34 PAGE 6
304 1 }
305
306 //-----------------------------------------------------------------------------
307 // ADC0_Init
308 //-----------------------------------------------------------------------------
309 //
310 // Return Value: None
311 // Parameters: None
312 //
313 // Configures ADC0 to make single-ended analog measurements on pin P2.5
314 //
315 //-----------------------------------------------------------------------------
316 void ADC0_Init (void)
317 {
318 1 ADC0CN = 0x02; // ADC0 disabled, normal tracking,
319 1 // conversion triggered on TMR2 overflow
320 1
321 1 REF0CN = 0x0E; // Enable on-chip VREF, select Vdd as
322 1 // voltage reference.
323 1
324 1 AMX0P = 0x11; // ADC0 positive input = P2.5
325 1 AMX0N = 0x1F; // ADC0 negative input = GND
326 1 // i.e., single ended mode
327 1
328 1 ADC0CF = ((SYSCLK/3000000)-1)<<3; // set SAR clock to 3MHz
329 1
330 1 ADC0CF |= 0x00; // right-justify results
331 1
332 1 EIE1 |= 0x08; // enable ADC0 conversion complete int.
333 1
334 1 AD0EN = 1; // enable ADC0
335 1 }
336
337 //-----------------------------------------------------------------------------
338 // UART0_Init
339 //-----------------------------------------------------------------------------
340 //
341 // Return Value: None
342 // Parameters: None
343 //
344 // Configure the UART0 using Timer1, for <BAUDRATE> and 8-N-1.
345 //
346 //-----------------------------------------------------------------------------
347 void UART0_Init (void)
348 {
349 1 SCON0 = 0x10; // SCON0: 8-bit variable bit rate
350 1 // level of STOP bit is ignored
351 1 // RX enabled
352 1 // ninth bits are zeros
353 1 // clear RI0 and TI0 bits
354 1 if (SYSCLK/BAUDRATE/2/256 < 1) {
355 2 TH1 = -(SYSCLK/BAUDRATE/2);
356 2 CKCON |= 0x08; // T1M = 1; SCA1:0 = xx
357 2 } else if (SYSCLK/BAUDRATE/2/256 < 4) {
358 2 TH1 = -(SYSCLK/BAUDRATE/2/4);
359 2 CKCON &= ~0x0B; // T1M = 0; SCA1:0 = 01
360 2 CKCON |= 0x01;
361 2 } else if (SYSCLK/BAUDRATE/2/256 < 12) {
362 2 TH1 = -(SYSCLK/BAUDRATE/2/12);
363 2 CKCON &= ~0x0B; // T1M = 0; SCA1:0 = 00
364 2 } else if (SYSCLK/BAUDRATE/2/256 < 48) {
365 2 TH1 = -(SYSCLK/BAUDRATE/2/48);
C51 COMPILER V8.08 F31X_ADC0_EXTERNALINPUT 03/20/2009 15:55:34 PAGE 7
366 2 CKCON &= ~0x0B; // T1M = 0; SCA1:0 = 10
367 2 CKCON |= 0x02;
368 2 } else {
369 2 while (1); // Error. Unsupported baud rate
370 2 }
371 1
372 1 TL1 = TH1; // init Timer1
373 1 TMOD &= ~0xf0; // TMOD: timer 1 in 8-bit autoreload
374 1 TMOD |= 0x20;
375 1 TR1 = 1; // START Timer1
376 1 TI0 = 1; // Indicate TX0 ready
377 1 }
378
379 //-----------------------------------------------------------------------------
380 // Interrupt Service Routines
381 //-----------------------------------------------------------------------------
382 //
383 //-----------------------------------------------------------------------------
384 // ADC0_ISR
385 //-----------------------------------------------------------------------------
386 //
387 // Return Value: None
388 // Parameters: None
389 //
390 // This ISR averages 2048 samples then prints the result to the terminal. The
391 // ISR is called after each ADC conversion which is triggered by Timer2.
392 //
393 //-----------------------------------------------------------------------------
394 void ADC0_ISR (void) interrupt 10
395 {
396 1
397 1 static unsigned long accumulator = 0; // accumulator for averaging
398 1 static unsigned int measurements = 2048; // measurement counter
399 1 unsigned long result=0;
400 1 unsigned long mV; // measured voltage in mV
401 1
402 1 AD0INT = 0; // clear ADC0 conversion complete flag
403 1
404 1 accumulator += ADC0;
405 1 measurements--;
406 1
407 1 if(measurements == 0)
408 1 {
409 2 measurements = 2048;
410 2 result = accumulator / 2048;
411 2 accumulator=0;
412 2
413 2 // The 10-bit ADC value is averaged across 2048 measurements.
414 2 // The measured voltage applied to P1.4 is then:
415 2 //
416 2 // Vref (mV)
417 2 // measurement (mV) = --------------- * result (bits)
418 2 // (2^10)-1 (bits)
419 2
420 2 mV = result * 3250 / 1023;
421 2 printf("P3.1 voltage: %ld mV\n",mV);
422 2 }
423 1
424 1 LED=~LED;
425 1 }
426
427 //-----------------------------------------------------------------------------
C51 COMPILER V8.08 F31X_ADC0_EXTERNALINPUT 03/20/2009 15:55:34 PAGE 8
428 // End Of File
429 //-----------------------------------------------------------------------------
MODULE INFORMATION: STATIC OVERLAYABLE
CODE SIZE = 558 ----
CONSTANT SIZE = 22 ----
XDATA SIZE = ---- ----
PDATA SIZE = ---- ----
DATA SIZE = 12 8
IDATA SIZE = ---- ----
BIT SIZE = ---- ----
END OF MODULE INFORMATION.
C51 COMPILATION COMPLETE. 0 WARNING(S), 0 ERROR(S)
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