1 //GoodFET SPI Application
4 //Higher level left to client application.
20 //This could be more accurate.
21 //Does it ever need to be?
23 #define SPIDELAY(x) delay(x)
25 #define SETMOSI P5OUT|=MOSI
26 #define CLRMOSI P5OUT&=~MOSI
27 #define SETCLK P5OUT|=SCK
28 #define CLRCLK P5OUT&=~SCK
29 #define READMISO (P5IN&MISO?1:0)
33 //! Set up the pins for SPI mode.
40 //! Read and write an SPI bit.
41 unsigned char spitrans8(unsigned char byte){
43 //This function came from the SPI Wikipedia article.
46 for (bit = 0; bit < 8; bit++) {
47 /* write MOSI on trailing edge of previous clock */
54 /* half a clock cycle before leading/rising edge */
58 /* half a clock cycle before trailing/falling edge */
61 /* read MISO on trailing edge */
69 //! Enable SPI writing
70 void spiflash_wrten(){
71 P5OUT&=~SS; //Drop !SS to begin transaction.
72 spitrans8(0x04);//Write Disable
73 P5OUT|=SS; //Raise !SS to end transaction.
74 P5OUT&=~SS; //Drop !SS to begin transaction.
75 spitrans8(0x06);//Write Enable
76 P5OUT|=SS; //Raise !SS to end transaction.
79 //! Grab the SPI flash status byte.
80 unsigned char spiflash_status(){
82 P5OUT|=SS; //Raise !SS to end transaction.
83 P5OUT&=~SS; //Drop !SS to begin transaction.
84 spitrans8(0x05);//GET STATUS
86 P5OUT|=SS; //Raise !SS to end transaction.
89 //! Grab the SPI flash status byte.
90 void spiflash_setstatus(unsigned char c){
91 P5OUT&=~SS; //Drop !SS to begin transaction.
92 spitrans8(0x01);//SET STATUS
94 P5OUT|=SS; //Raise !SS to end transaction.
98 //! Handles a monitor command.
99 void spihandle(unsigned char app,
105 //Raise !SS to end transaction, just in case we forgot.
109 //PEEK and POKE might come later.
112 P5OUT&=~SS; //Drop !SS to begin transaction.
114 cmddata[i]=spitrans8(cmddata[i]);
115 P5OUT|=SS; //Raise !SS to end transaction.
116 txdata(app,verb,len);
118 case SPI_JEDEC://Grab 3-byte JEDEC ID.
119 P5OUT&=~SS; //Drop !SS to begin transaction.
123 cmddata[i]=spitrans8(cmddata[i]);
124 txdata(app,verb,len);
125 P5OUT|=SS; //Raise !SS to end transaction.
127 case PEEK://Grab 128 bytes from an SPI Flash ROM
128 P5OUT&=~SS; //Drop !SS to begin transaction.
129 spitrans8(0x03);//Flash Read Command
130 len=3;//write 3 byte pointer
132 spitrans8(cmddata[i]);
133 len=0x80;//128 byte chunk
135 cmddata[i]=spitrans8(0);
136 P5OUT|=SS; //Raise !SS to end transaction.
137 txdata(app,verb,len);
139 case POKE://Poke up bytes from an SPI Flash ROM.
140 spiflash_setstatus(0x02);
143 P5OUT&=~SS; //Drop !SS to begin transaction.
144 spitrans8(0x02); //Poke command.
146 //First three bytes are address, then data.
148 spitrans8(cmddata[i]);
149 P5OUT|=SS; //Raise !SS to end transaction.
150 while(spiflash_status()&0x01);//while busy
151 txdata(app,verb,len);
153 case SPI_ERASE://Erase the SPI Flash ROM.
155 P5OUT&=~SS; //Drop !SS to begin transaction.
156 spitrans8(0xC7);//Chip Erase
157 P5OUT|=SS; //Raise !SS to end transaction.