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1 | /* | |
2 | * WiFly UART-SPI bridge Example | |
3 | * Copyright (c) 2010 SparkFun Electronics. All right reserved. | |
4 | * Written by Chris Taylor | |
5 | * | |
6 | * This code was written to demonstrate the WiFly Shield from SparkFun Electronics | |
7 | * | |
8 | * This code will initialize and test the SC16IS750 UART-SPI bridge, and allow | |
9 | * transparent communication with the device from a terminal. | |
10 | * | |
11 | * http://www.sparkfun.com | |
12 | */ | |
13 | ||
14 | char dummy; //fixes bug in GUI / complier | |
15 | ||
16 | // SCI16IS750 Registers | |
17 | #define THR 0x00 << 3 | |
18 | #define RHR 0x00 << 3 | |
19 | #define IER 0x01 << 3 | |
20 | #define FCR 0x02 << 3 | |
21 | #define IIR 0x02 << 3 | |
22 | #define LCR 0x03 << 3 | |
23 | #define MCR 0x04 << 3 | |
24 | #define LSR 0x05 << 3 | |
25 | #define MSR 0x06 << 3 | |
26 | #define SPR 0x07 << 3 | |
27 | #define TXFIFO 0x08 << 3 | |
28 | #define RXFIFO 0x09 << 3 | |
29 | #define DLAB 0x80 << 3 | |
30 | #define IODIR 0x0A << 3 | |
31 | #define IOSTATE 0x0B << 3 | |
32 | #define IOINTMSK 0x0C << 3 | |
33 | #define IOCTRL 0x0E << 3 | |
34 | #define EFCR 0x0F << 3 | |
35 | ||
36 | #define DLL 0x00 << 3 | |
37 | #define DLM 0x01 << 3 | |
38 | #define EFR 0x02 << 3 | |
39 | #define XON1 0x04 << 3 | |
40 | #define XON2 0x05 << 3 | |
41 | #define XOFF1 0x06 << 3 | |
42 | #define XOFF2 0x07 << 3 | |
43 | ||
44 | // Arduino SPI pins | |
45 | #define CS 10 | |
46 | #define MOSI 11 | |
47 | #define MISO 12 | |
48 | #define SCK 13 | |
49 | ||
50 | // Communication flags and variables | |
51 | char incoming_data; | |
52 | char TX_Fifo_Address = THR; | |
53 | ||
54 | char clr = 0; | |
55 | char polling = 0; | |
56 | ||
57 | // SC16IS750 Configuration Parameters | |
58 | struct SPI_UART_cfg | |
59 | { | |
60 | char DivL,DivM,DataFormat,Flow; | |
61 | }; | |
62 | ||
63 | struct SPI_UART_cfg SPI_Uart_config = { | |
64 | 0x50,0x00,0x03,0x10}; | |
65 | ||
66 | void setup() | |
67 | { | |
68 | // Initialize SPI pins | |
69 | pinMode(MOSI, OUTPUT); | |
70 | pinMode(MISO, INPUT); | |
71 | pinMode(SCK,OUTPUT); | |
72 | pinMode(CS,OUTPUT); | |
73 | digitalWrite(CS,HIGH); //disable device | |
74 | ||
75 | SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR1)|(1<<SPR0); | |
76 | clr=SPSR; | |
77 | clr=SPDR; | |
78 | delay(10); | |
79 | ||
80 | Serial.begin(9600); | |
81 | Serial.println("\n\r\n\rWiFly Shield Terminal Routine"); | |
82 | ||
83 | // Test SPI communication | |
84 | if(SPI_Uart_Init()){ | |
85 | Serial.println("Bridge initialized successfully!"); | |
86 | } | |
87 | else{ | |
88 | Serial.println("Could not initialize bridge, locking up.\n\r"); | |
89 | while(1); | |
90 | } | |
91 | } | |
92 | ||
93 | void loop() | |
94 | { | |
95 | // Poll for new data in SC16IS750 Recieve buffer | |
96 | if(SPI_Uart_ReadByte(LSR) & 0x01) | |
97 | { | |
98 | polling = 1; | |
99 | while(polling) | |
100 | { | |
101 | if((SPI_Uart_ReadByte(LSR) & 0x01)) | |
102 | { | |
103 | incoming_data = SPI_Uart_ReadByte(RHR); | |
104 | Serial.print(incoming_data); | |
105 | } | |
106 | else | |
107 | { | |
108 | polling = 0; | |
109 | } | |
110 | } | |
111 | ||
112 | } | |
113 | // Otherwise, send chars from terminal to SC16IS750 | |
114 | else if(Serial.available()) | |
115 | { | |
116 | incoming_data = Serial.read(); | |
117 | select(); | |
118 | spi_transfer(0x00); // Transmit command | |
119 | spi_transfer(incoming_data); | |
120 | deselect(); | |
121 | } | |
122 | ||
123 | } | |
124 | ||
125 | ||
126 | ||
127 | char SPI_Uart_Init(void) | |
128 | // Initialize SC16IS750 | |
129 | { | |
130 | char data = 0; | |
131 | ||
132 | SPI_Uart_WriteByte(LCR,0x80); // 0x80 to program baudrate | |
133 | SPI_Uart_WriteByte(DLL,SPI_Uart_config.DivL); //0x50 = 9600 with Xtal = 12.288MHz | |
134 | SPI_Uart_WriteByte(DLM,SPI_Uart_config.DivM); | |
135 | ||
136 | SPI_Uart_WriteByte(LCR, 0xBF); // access EFR register | |
137 | SPI_Uart_WriteByte(EFR, SPI_Uart_config.Flow); // enable enhanced registers | |
138 | SPI_Uart_WriteByte(LCR, SPI_Uart_config.DataFormat); // 8 data bit, 1 stop bit, no parity | |
139 | SPI_Uart_WriteByte(FCR, 0x06); // reset TXFIFO, reset RXFIFO, non FIFO mode | |
140 | SPI_Uart_WriteByte(FCR, 0x01); // enable FIFO mode | |
141 | ||
142 | // Perform read/write test to check if UART is working | |
143 | SPI_Uart_WriteByte(SPR,'H'); | |
144 | data = SPI_Uart_ReadByte(SPR); | |
145 | ||
146 | if(data == 'H'){ | |
147 | return 1; | |
148 | } | |
149 | else{ | |
150 | return 0; | |
151 | } | |
152 | ||
153 | } | |
154 | ||
155 | void SPI_Uart_WriteByte(char address, char data) | |
156 | // Write byte to register address on SC16IS750 | |
157 | { | |
158 | long int length; | |
159 | char senddata[2]; | |
160 | senddata[0] = address; | |
161 | senddata[1] = data; | |
162 | ||
163 | select(); | |
164 | length = SPI_Write(senddata, 2); | |
165 | deselect(); | |
166 | } | |
167 | ||
168 | long int SPI_Write(char* srcptr, long int length) | |
169 | // Send entire string to SC16IS750 | |
170 | { | |
171 | for(long int i = 0; i < length; i++) | |
172 | { | |
173 | spi_transfer(srcptr[i]); | |
174 | } | |
175 | return length; | |
176 | } | |
177 | ||
178 | void SPI_Uart_WriteArray(char *data, long int NumBytes) | |
179 | // Send entire string to THR of SC16IS750 | |
180 | { | |
181 | long int length; | |
182 | select(); | |
183 | length = SPI_Write(&TX_Fifo_Address,1); | |
184 | ||
185 | while(NumBytes > 16) // Split array into 16 character chunks | |
186 | { | |
187 | length = SPI_Write(data,16); | |
188 | NumBytes -= 16; | |
189 | data += 16; | |
190 | } | |
191 | length = SPI_Write(data,NumBytes); | |
192 | ||
193 | deselect(); | |
194 | } | |
195 | ||
196 | char SPI_Uart_ReadByte(char address) | |
197 | // Read from SC16IS750 register | |
198 | { | |
199 | char data; | |
200 | ||
201 | address = (address | 0x80); | |
202 | ||
203 | select(); | |
204 | spi_transfer(address); | |
205 | data = spi_transfer(0xFF); | |
206 | deselect(); | |
207 | return data; | |
208 | } | |
209 | ||
210 | void SPI_Uart_println(char *data) | |
211 | // Write string to SC16IS750 followed by a carriage return | |
212 | { | |
213 | SPI_Uart_WriteArray(data,strlen(data)); | |
214 | SPI_Uart_WriteByte(THR, 0x0d); | |
215 | } | |
216 | ||
217 | void SPI_Uart_print(char *data) | |
218 | // Write string to SC16IS750, no carriage return | |
219 | { | |
220 | SPI_Uart_WriteArray(data,strlen(data)); | |
221 | } | |
222 | ||
223 | char spi_transfer(volatile char data) | |
224 | { | |
225 | SPDR = data; // Start the transmission | |
226 | while (!(SPSR & (1<<SPIF))) // Wait for the end of the transmission | |
227 | { | |
228 | }; | |
229 | return SPDR; // return the received byte | |
230 | } | |
231 | ||
232 | void select(void) | |
233 | { | |
234 | digitalWrite(CS,LOW); | |
235 | } | |
236 | ||
237 | void deselect(void) | |
238 | { | |
239 | digitalWrite(CS,HIGH); | |
240 | } |