3线USART程序，MPLAB

3线USART程序，MPLAB


源程序如下:

1. /**********************************************************************
   
2. * ?2008 Microchip Technology Inc.
   
3. *
   
4. * FileName:        main.c
   
5. * Dependencies:    uart2.h
   
6. * Processor:       PIC24F
   
7. * Compiler:        MPLAB?C30
   
8. * Tested On:           PIC24F Explorer 16
   
9. *
   
10. * SOFTWARE LICENSE AGREEMENT:
    
11. * Microchip Technology Incorporated ("Microchip") retains all ownership and
    
12. * intellectual property rights in the code accompanying this message and in all
    
13. * derivatives hereto.  You may use this code, and any derivatives created by
    
14. * any person or entity by or on your behalf, exclusively with Microchip's
    
15. * proprietary products.  Your acceptance and/or use of this code constitutes
    
16. * agreement to the terms and conditions of this notice.
    
17. *
    
18. * CODE ACCOMPANYING THIS MESSAGE IS SUPPLIED BY MICROCHIP "AS IS".  NO
    
19. * WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED
    
20. * TO, IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A
    
21. * PARTICULAR PURPOSE APPLY TO THIS CODE, ITS INTERACTION WITH MICROCHIP'S
    
22. * PRODUCTS, COMBINATION WITH ANY OTHER PRODUCTS, OR USE IN ANY APPLICATION.
    
23. *
    
24. * YOU ACKNOWLEDGE AND AGREE THAT, IN NO EVENT, SHALL MICROCHIP BE LIABLE, WHETHER
    
25. * IN CONTRACT, WARRANTY, TORT (INCLUDING NEGLIGENCE OR BREACH OF STATUTORY DUTY),
    
26. * STRICT LIABILITY, INDEMNITY, CONTRIBUTION, OR OTHERWISE, FOR ANY INDIRECT, SPECIAL,
    
27. * PUNITIVE, EXEMPLARY, INCIDENTAL OR CONSEQUENTIAL LOSS, DAMAGE, FOR COST OR EXPENSE OF
    
28. * ANY KIND WHATSOEVER RELATED TO THE CODE, HOWSOEVER CAUSED, EVEN IF MICROCHIP HAS BEEN
    
29. * ADVISED OF THE POSSIBILITY OR THE DAMAGES ARE FORESEEABLE.  TO THE FULLEST EXTENT
    
30. * ALLOWABLE BY LAW, MICROCHIP'S TOTAL LIABILITY ON ALL CLAIMS IN ANY WAY RELATED TO
    
31. * THIS CODE, SHALL NOT EXCEED THE PRICE YOU PAID DIRECTLY TO MICROCHIP SPECIFICALLY TO
    
32. * HAVE THIS CODE DEVELOPED.
    
33. *
    
34. * You agree that you are solely responsible for testing the code and
    
35. * determining its suitability.  Microchip has no obligation to modify, test,
    
36. * certify, or support the code.
    
37. *
    
38. * REVISION HISTORY:
    
39. *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    
40. * Author            Date              Comments on this revision
    
41. *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    
42. * Albert Z.         12/26/08    Original Release
    
43. *
    
44. *~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    
45. * ADDITIONAL NOTES:
    
46. * Small, bare bones program to guide designers with UART implementation
    
47. * To run the example, plug DB9 cable to Terminal (9600,8,N,1) -
    
48. * Data sent from TERMINAL will be represented as binary equivalent
    
49. * of ASCII on 7 LSB LEDs of Explorer 16 development board
    
50. *
    
51. * Data is sent from Explorer 16 by pressing S3 - S6.  A single letter will
    
52. * be transmitted upon each keypress.
    
53. *
    
54. * Peripheral Library was not utilized, Bit Addressing was used in order
    
55. * to show all details involved in initialization of UART.
    
56. *
    
57. * This code example has been tested on Explorer 16 Development Board
    
58. * with PIC24FJ128GA010, PIC24FJ256GA110 and PIC24FJ256GB110 PIMs.
    
59. **********************************************************************/
    
60. #include "p24fxxxx.h"
    
61. #include "uart2.h"
    
62. 
    
63. #if defined (__PIC24FJ256GB110__)        //Defined by MPLAB when using 24FJ256GB110 device
    
64.     _CONFIG1( JTAGEN_OFF & GCP_OFF & GWRP_OFF & COE_OFF & FWDTEN_OFF & ICS_PGx2)
    
65.     _CONFIG2( IESO_OFF & FCKSM_CSDCMD & OSCIOFNC_OFF & POSCMOD_XT & FNOSC_PRI & PLLDIV_DIV2 & IOL1WAY_ON)
    
66.     _CONFIG3( WPCFG_WPCFGDIS & WPDIS_WPDIS)                //Disable erase/write protect of all memory regions.
    
67. #elif defined (__PIC24FJ256GA110__)        //Defined by MPLAB when using 24FJ256GA110 device
    
68.     _CONFIG1( JTAGEN_OFF & GCP_OFF & GWRP_OFF & COE_OFF & FWDTEN_OFF & ICS_PGx2 )
    
69.     _CONFIG2( FCKSM_CSDCMD & OSCIOFNC_OFF & POSCMOD_XT & FNOSC_PRI & IOL1WAY_ON)
    
70.     _CONFIG3( WPCFG_WPCFGDIS & WPDIS_WPDIS)                //Disable erase/write protect of all memory regions.
    
71. #elif defined (__PIC24FJ128GA010__)
    
72.         // JTAG/Code Protect/Write Protect/Clip-on Emulation mode
    
73.         // Watchdog Timer/ICD pins select
    
74.         _CONFIG1(JTAGEN_OFF & GCP_OFF & GWRP_OFF & COE_OFF & FWDTEN_OFF & ICS_PGx2)
    
75.         // Disable CLK switch and CLK monitor, OSCO or Fosc/2, HS oscillator,
    
76.         // Primary oscillator
    
77.         _CONFIG2(FCKSM_CSDCMD & OSCIOFNC_OFF & POSCMOD_XT & FNOSC_PRI)
    
78. #endif
    
79. 
    
80. #define TRUE        1
    
81. #define FALSE        0
    
82. 
    
83. unsigned char S3Flag, S4Flag, S5Flag, S6Flag;
    
84. 
    
85. void __attribute__ ((interrupt, no_auto_psv)) _U2RXInterrupt(void) {
    
86.         LATA = U2RXREG;
    
87.         IFS1bits.U2RXIF = 0;
    
88. }
    
89. void __attribute__ ((interrupt, no_auto_psv)) _U2TXInterrupt(void) {
    
90.         IFS1bits.U2TXIF = 0;
    
91. }
    
92. 
    
93. 
    
94. void InitUART2(void)
    
95. {
    
96.         // This is an EXAMPLE, so brutal typing goes into explaining all bit sets
    
97. 
    
98.         // The Explorer 16 board has a DB9 connector wired to UART2, so we will
    
99.         // be configuring this port only
    
100. 
     
101.         // configure U2MODE
     
102.         U2MODEbits.UARTEN = 0;        // Bit15 TX, RX DISABLED, ENABLE at end of func
     
103.         U2MODEbits.USIDL = 0;        // Bit13 Continue in Idle
     
104.         U2MODEbits.IREN = 0;        // Bit12 No IR translation
     
105.         U2MODEbits.RTSMD = 0;        // Bit11 Simplex Mode
     
106.         U2MODEbits.UEN = 0;                // Bits8,9 TX,RX enabled, CTS,RTS not
     
107.         U2MODEbits.WAKE = 0;        // Bit7 No Wake up (since we don't sleep here)
     
108.         U2MODEbits.LPBACK = 0;        // Bit6 No Loop Back
     
109.         U2MODEbits.ABAUD = 0;        // Bit5 No Autobaud (would require sending '55')
     
110.         U2MODEbits.RXINV = 0;        // Bit4 IdleState = 1
     
111.         U2MODEbits.BRGH = 0;        // Bit3 16 clocks per bit period
     
112.         U2MODEbits.PDSEL = 0;        // Bits1,2 8bit, No Parity
     
113.         U2MODEbits.STSEL = 0;        // Bit0 One Stop Bit
     
114.        
     
115.         U2BRG = BAUDRATEREG2;        // baud rate
     
116. 
     
117.         // Load all values in for U1STA SFR
     
118.         U2STAbits.UTXISEL1 = 0;        //Bit15 Int when Char is transferred (1/2 config!)
     
119.         U2STAbits.UTXINV = 0;        //Bit14 N/A, IRDA config
     
120.         U2STAbits.UTXISEL0 = 0;        //Bit13 Other half of Bit15
     
121.         U2STAbits.UTXBRK = 0;        //Bit11 Disabled
     
122.         U2STAbits.UTXEN = 0;        //Bit10 TX pins controlled by periph
     
123.         U2STAbits.UTXBF = 0;        //Bit9 *Read Only Bit*
     
124.         U2STAbits.TRMT = 0;                //Bit8 *Read Only bit*
     
125.         U2STAbits.URXISEL = 0;        //Bits6,7 Int. on character recieved
     
126.         U2STAbits.ADDEN = 0;        //Bit5 Address Detect Disabled
     
127.         U2STAbits.RIDLE = 0;        //Bit4 *Read Only Bit*
     
128.         U2STAbits.PERR = 0;                //Bit3 *Read Only Bit*
     
129.         U2STAbits.FERR = 0;                //Bit2 *Read Only Bit*
     
130.         U2STAbits.OERR = 0;                //Bit1 *Read Only Bit*
     
131.         U2STAbits.URXDA = 0;        //Bit0 *Read Only Bit*
     
132. 
     
133.         IFS1bits.U2TXIF = 0;        // Clear the Transmit Interrupt Flag
     
134.         IEC1bits.U2TXIE = 1;        // Enable Transmit Interrupts
     
135.         IFS1bits.U2RXIF = 0;        // Clear the Recieve Interrupt Flag
     
136.         IEC1bits.U2RXIE = 1;        // Enable Recieve Interrupts
     
137. 
     
138.         U2MODEbits.UARTEN = 1;        // And turn the peripheral on
     
139. 
     
140.         U2STAbits.UTXEN = 1;
     
141. }
     
142. 
     
143. void InitPorts(void)
     
144. {
     
145.         // S3 (portD Pin 6, chosen as trigger for sending 'M' to UART)
     
146.         // S6 (portD Pin 7, chosen as trigger for sending 'C' to UART)
     
147.         // S5 (portA Pin 7, chosen as trigger for sending 'H' to UART)
     
148.         // S4 (portD Pin 13, chosen as trigger for sending 'P' to UART)
     
149. 
     
150.         TRISD = 0x20C0;        // D6,7,13 inputs
     
151.         TRISA = 0x0080;        // only 0th bit needs be output. A7 is input
     
152.         S3Flag = S4Flag = S5Flag = S6Flag = 0;        // Some Debounce Flags
     
153. }
     
154. 
     
155. void SoftwareDebounce(void)
     
156. {
     
157.         if(PORTDbits.RD6 == FALSE) {
     
158.                 if( S3Flag == FALSE ) {
     
159.                         S3Flag = TRUE;
     
160.                 }
     
161.         } else {
     
162.                 if ( S3Flag == TRUE ) {
     
163.                         U2TXREG = 'M';
     
164.                         S3Flag = FALSE;
     
165.                 }       
     
166.         }
     
167. 
     
168.         if(PORTDbits.RD7 == FALSE) {
     
169.                 if( S6Flag == FALSE ) {
     
170.                         S6Flag = TRUE;
     
171.                 }
     
172.         } else {
     
173.                 if ( S6Flag == TRUE ) {
     
174.                         U2TXREG = 'C';
     
175.                         S6Flag = FALSE;
     
176.                 }       
     
177.         }
     
178. 
     
179.         if(PORTAbits.RA7 == FALSE) {
     
180.                 if( S5Flag == FALSE ) {
     
181.                         S5Flag = TRUE;
     
182.                 }
     
183.         } else {
     
184.                 if ( S5Flag == TRUE ) {
     
185.                         U2TXREG = 'H';
     
186.                         S5Flag = FALSE;
     
187.                 }       
     
188.         }
     
189. 
     
190.         if(PORTDbits.RD13 == FALSE) {
     
191.                 if( S4Flag == FALSE ) {
     
192.                         S4Flag = TRUE;
     
193.                 }
     
194.         } else {
     
195.                 if ( S4Flag == TRUE ) {
     
196.                         U2TXREG = 'P';
     
197.                         S4Flag = FALSE;
     
198.                 }       
     
199.         }
     
200. }
     
201. 
     
202. int main(void)
     
203. {
     
204.         unsigned char i;
     
205.         // Disable Watch Dog Timer
     
206.         RCONbits.SWDTEN = 0;
     
207.        
     
208.         // I/O remap, PPS
     
209. #if defined (__PIC24FJ256GB110__) || defined (__PIC24FJ256GA110__)
     
210.         // remap pins before intialising SPI2
     
211.         // Unlock Registers
     
212.         __builtin_write_OSCCONL(OSCCON & 0xbf);
     
213.         // Configure Input Functions **********************
     
214.         // Assign UART2RX To Pin RP10
     
215.         RPINR19bits.U2RXR = 10;
     
216.         // Configure Output Functions *********************
     
217.         // Assign UART2TX To Pin RP17
     
218.         RPOR8bits.RP17R = U2TX_IO;
     
219.         // Lock Registers
     
220.         __builtin_write_OSCCONL(OSCCON | 0x40);
     
221. #endif
     
222. 
     
223. 
     
224.         InitUART2();        // Initialize UART2 for 9600,8,N,1 TX/RX
     
225. 
     
226.         InitPorts();        // LEDs outputs, Switches Inputs
     
227. 
     
228.         while(1) {        // The ever versatile Infinite Loop!
     
229.                 for (i = 0; i < 100; i++);
     
230.                 SoftwareDebounce();
     
231.         }
     
232. }
     

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