📄 pc_io.lst
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C51 COMPILER V6.10 PC_IO 04/18/2001 16:10:03 PAGE 1
C51 COMPILER V6.10, COMPILATION OF MODULE PC_IO
OBJECT MODULE PLACED IN .\PC_IO.OBJ
COMPILER INVOKED BY: C:\KEIL\C51\BIN\C51.EXE .\PC_IO.c OPTIMIZE(6,SIZE) BROWSE DEBUG OBJECTEXTEND
stmt level source
1 /*------------------------------------------------------------------*-
2
3 PC_IO.C (v1.01)
4
5 ------------------------------------------------------------------
6
7 Core files for simple PC link library for 8051 family
8
9 Uses the USART, and Pins 3.1 (Tx) and 3.0 (Rx)
10
11 See text for details (Chapter 18).
12
13
14 COPYRIGHT
15 ---------
16
17 This code is from the book:
18
19 PATTERNS FOR TIME-TRIGGERED EMBEDDED SYSTEMS by Michael J. Pont
20 [Pearson Education, 2001; ISBN: 0-201-33138-1].
21
22 This code is copyright (c) 2001 by Michael J. Pont.
23
24 See book for copyright details and other information.
25
26 -*------------------------------------------------------------------*/
27
28 #include "Main.h"
29 #include "PC_IO.h"
30
31 // ------ Public variable definitions ------------------------------
32
33 tByte In_read_index_G; // Data in buffer that has been read
34 tByte In_waiting_index_G; // Data in buffer not yet read
35
36 tByte Out_written_index_G; // Data in buffer that has been written
37 tByte Out_waiting_index_G; // Data in buffer not yet written
38
39 // ------ Public variable declarations -----------------------------
40
41 // The error code variable
42 //
43 // See Main.H for port on which error codes are displayed
44 // and for details of error codes
45 extern tByte Error_code_G;
46
47 // ------ Private function prototypes ------------------------------
48
49 void PC_LINK_IO_Send_Char(const char);
50
51 // ------ Private constants ----------------------------------------
52
53 // The receive buffer length
54 #define RECV_BUFFER_LENGTH 8
55
C51 COMPILER V6.10 PC_IO 04/18/2001 16:10:03 PAGE 2
56 // The transmit buffer length
57 #define TRAN_BUFFER_LENGTH 50
58
59 #define XON 0x11
60 #define XOFF 0x13
61
62 // ------ Private variables ----------------------------------------
63
64 static tByte Recv_buffer[RECV_BUFFER_LENGTH];
65 static tByte Tran_buffer[TRAN_BUFFER_LENGTH];
66
67
68 /*------------------------------------------------------------------*-
69
70 PC_LINK_IO_Update()
71
72 Checks for character in the UART (hardware) receive buffer
73 Sends next character from the software transmit buffer
74
75 -*------------------------------------------------------------------*/
76 void PC_LINK_IO_Update(void)
77 {
78 1 // Deal with transmit bytes here
79 1
80 1 // Is there any data ready to send?
81 1 if (Out_written_index_G < Out_waiting_index_G)
82 1 {
83 2 PC_LINK_IO_Send_Char(Tran_buffer[Out_written_index_G]);
84 2
85 2 Out_written_index_G++;
86 2 }
87 1 else
88 1 {
89 2 // No data to send - just reset the buffer index
90 2 Out_waiting_index_G = 0;
91 2 Out_written_index_G = 0;
92 2 }
93 1
94 1 // Only dealing with received bytes here
95 1 // -> Just check the RI flag
96 1 if (RI == 1)
97 1 {
98 2 // Flag only set when a valid stop bit is received,
99 2 // -> data ready to be read into the received buffer
100 2
101 2 // Want to read into index 0, if old data has been read
102 2 // (simple ~circular buffer)
103 2 if (In_waiting_index_G == In_read_index_G)
104 2 {
105 3 In_waiting_index_G = 0;
106 3 In_read_index_G = 0;
107 3 }
108 2
109 2 // Read the data from USART buffer
110 2 Recv_buffer[In_waiting_index_G] = SBUF;
111 2
112 2 if (In_waiting_index_G < RECV_BUFFER_LENGTH)
113 2 {
114 3 // Increment without overflowing buffer
115 3 In_waiting_index_G++;
116 3 }
117 2
C51 COMPILER V6.10 PC_IO 04/18/2001 16:10:03 PAGE 3
118 2 RI = 0; // Clear RT flag
119 2 }
120 1 }
121
122 /*------------------------------------------------------------------*-
123
124 PC_LINK_IO_Write_Char_To_Buffer()
125
126 Stores a character in the 'write' buffer, ready for
127 later transmission
128
129 -*------------------------------------------------------------------*/
130 void PC_LINK_IO_Write_Char_To_Buffer(const char CHARACTER)
131 {
132 1 // Write to the buffer *only* if there is space
133 1 if (Out_waiting_index_G < TRAN_BUFFER_LENGTH)
134 1 {
135 2 Tran_buffer[Out_waiting_index_G] = CHARACTER;
136 2 Out_waiting_index_G++;
137 2 }
138 1 else
139 1 {
140 2 // Write buffer is full
141 2 // Increase the size of TRAN_BUFFER_LENGTH
142 2 // or increase the rate at which UART 'update' function is called
143 2 // or reduce the amount of data sent to PC
144 2 Error_code_G = ERROR_USART_WRITE_CHAR;
145 2 }
146 1 }
147
148
149 /*------------------------------------------------------------------*-
150
151 PC_LINK_IO_Write_String_To_Buffer()
152
153 Copies a (null terminated) string to the character buffer.
154 (The contents of the buffer are then passed over the serial link)
155
156 STR_PTR - Pointer to the NULL-TERMINATED string.
157
158 -*------------------------------------------------------------------*/
159 void PC_LINK_IO_Write_String_To_Buffer(const char* const STR_PTR)
160 {
161 1 tByte i = 0;
162 1
163 1 while (STR_PTR[i] != '\0')
164 1 {
165 2 PC_LINK_IO_Write_Char_To_Buffer(STR_PTR[i]);
166 2 i++;
167 2 }
168 1 }
169
170 /*------------------------------------------------------------------*-
171
172 PC_LINK_IO_Get_Char_From_Buffer()
173
174 Retrieves a character from the (software) buffer, if available
175
176 The character from the buffer is returned, or - if no
177 data are available - PC_LINK_IO_NO_CHAR is returned.
178
179 -*------------------------------------------------------------------*/
C51 COMPILER V6.10 PC_IO 04/18/2001 16:10:03 PAGE 4
180 char PC_LINK_IO_Get_Char_From_Buffer(void)
181 {
182 1 char Ch = PC_LINK_IO_NO_CHAR;
183 1
184 1 // If there is new data in the buffer
185 1 if (In_read_index_G < In_waiting_index_G)
186 1 {
187 2 Ch = Recv_buffer[In_read_index_G];
188 2
189 2 if (In_read_index_G < RECV_BUFFER_LENGTH)
190 2 {
191 3 In_read_index_G++;
192 3 }
193 2 }
194 1
195 1 return Ch;
196 1 }
197
198 /*------------------------------------------------------------------*-
199
200 PC_LINK_IO_Send_Char()
201
202 Based on Keil sample code, with added (loop) timeouts.
203 Implements Xon / Off control.
204
205 Uses on-chip UART hardware.
206
207 -*------------------------------------------------------------------*/
208 void PC_LINK_IO_Send_Char(const char CHARACTER)
209 {
210 1 tLong Timeout1 = 0;
211 1 tLong Timeout2 = 0;
212 1
213 1 if (CHARACTER == '\n')
214 1 {
215 2 if (RI)
216 2 {
217 3 if (SBUF == XOFF)
218 3 {
219 4 Timeout2 = 0;
220 4 do {
221 5 RI = 0;
222 5
223 5 // Wait for uart (with simple timeout)
224 5 Timeout1 = 0;
225 5 while ((++Timeout1) && (RI == 0));
226 5
227 5 if (Timeout1 == 0)
228 5 {
229 6 // USART did not respond - error
230 6 Error_code_G = ERROR_USART_TI;
231 6 return;
232 6 }
233 5
234 5 } while ((++Timeout2) && (SBUF != XON));
235 4
236 4 if (Timeout2 == 0)
237 4 {
238 5 // uart did not respond - error
239 5 Error_code_G = ERROR_USART_TI;
240 5 return;
241 5 }
C51 COMPILER V6.10 PC_IO 04/18/2001 16:10:03 PAGE 5
242 4
243 4 RI = 0;
244 4 }
245 3 }
246 2
247 2 Timeout1 = 0;
248 2 while ((++Timeout1) && (TI == 0));
249 2
250 2 if (Timeout1 == 0)
251 2 {
252 3 // uart did not respond - error
253 3 Error_code_G = ERROR_USART_TI;
254 3 return;
255 3 }
256 2
257 2 TI = 0;
258 2 SBUF = 0x0d; // output CR
259 2 }
260 1
261 1 if (RI)
262 1 {
263 2 if (SBUF == XOFF)
264 2 {
265 3 Timeout2 = 0;
266 3
267 3 do {
268 4 RI = 0;
269 4
270 4 // Wait for USART (with simple timeout)
271 4 Timeout1 = 0;
272 4 while ((++Timeout1) && (RI == 0));
273 4
274 4 if (Timeout1 == 0)
275 4 {
276 5 // USART did not respond - error
277 5 Error_code_G = ERROR_USART_TI;
278 5 return;
279 5 }
280 4
281 4 } while ((++Timeout2) && (SBUF != XON));
282 3
283 3 RI = 0;
284 3 }
285 2 }
286 1
287 1 Timeout1 = 0;
288 1 while ((++Timeout1) && (TI == 0));
289 1
290 1 if (Timeout1 == 0)
291 1 {
292 2 // USART did not respond - error
293 2 Error_code_G = ERROR_USART_TI;
294 2 return;
295 2 }
296 1
297 1 TI = 0;
298 1
299 1 SBUF = CHARACTER;
300 1 }
301
302
303 /*------------------------------------------------------------------*-
C51 COMPILER V6.10 PC_IO 04/18/2001 16:10:03 PAGE 6
304 ---- END OF FILE -------------------------------------------------
305 -*------------------------------------------------------------------*/
MODULE INFORMATION: STATIC OVERLAYABLE
CODE SIZE = 457 ----
CONSTANT SIZE = ---- ----
XDATA SIZE = ---- ----
PDATA SIZE = ---- ----
DATA SIZE = 62 12
IDATA SIZE = ---- ----
BIT SIZE = ---- ----
END OF MODULE INFORMATION.
C51 COMPILATION COMPLETE. 0 WARNING(S), 0 ERROR(S)
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