update nrf24 ring

radio/nrf24L01/nrf-ftdi-ring.c

@@ -69,6 +69,7 @@ uint8_t read_register(uint8_t reg){
    return temp;
 }
 void write_register(uint8_t reg, uint8_t val){
+   //must be in standby mode before calling this function!
    PORTC.OUTCLR = SS_BM; //SS low 
    _delay_us(1);     
    SPIC.DATA = W_REGISTER | reg; while(!(SPIC.STATUS & SPI_IF_bm)) {};
@@ -77,18 +78,18 @@ void write_register(uint8_t reg, uint8_t val){
    _delay_us(1);
 }
 
-
 USART_data_t USART_data;
 
 uint8_t token = 0; //token to pass
 uint8_t tempval = 0;
 const int pll_delay_us = 130;
+const int ce_delay_us = 10;
 
 void check_registers(uint8_t id){
-   //debug only
+   //for debug only
    //enter standby so we can write to configuration register.
    PORTC.OUTCLR = CE_BM; 
-   _delay_us(10);         
+   _delay_us(ce_delay_us);         
 
    PORTC.OUTCLR = SS_BM; //SS low  
    _delay_us(10);            
@@ -104,63 +105,16 @@ void check_registers(uint8_t id){
    usart_send_byte(&USART_data,config);
    usart_send_byte(&USART_data,token);
    usart_send_byte(&USART_data,10);
-
-   //interrupts
-   /*if (!(PORTC.IN & IRQ_BM)){
-      usart_send_byte(&USART_data,1);
-   } 
-   //clear interrupt on MAX_RT
-   PORTC.OUTCLR = SS_BM; //SS low  
-   _delay_ms(1);            
-   SPIC.DATA = W_REGISTER | STATUS; while(!(SPIC.STATUS & SPI_IF_bm)) {};
-   SPIC.DATA |= MAX_RT; while(!(SPIC.STATUS & SPI_IF_bm)) {};  //write 1 to MAX_RT bit
-   PORTC.OUTSET = SS_BM; //SS high
-   _delay_ms(1);
-   //interrupts
-   if (!(PORTC.IN & IRQ_BM)){
-      usart_send_byte(&USART_data,2);
-   }*/
 }
 
-// nRF24L01+ must be in a standby or power down mode before writing to the configuration registers. 
-
-//overview
-// - turn off autoretransmit
-// - MAX_RT interrupts on IRQ
-// - set interrupt service routine on rising edge of IRQ (RX_DR)
-// - set interrupt service routing on USART RX
-// - enter RX mode PRIM_RX = 1 (SPI transaction), CE = 1
-// - When IRQ interupt, 
-//    - enter standby (CE=0)
-//    - read payload (SPI transaction)
-//    - process data and put result in TX fifo 
-//    - enter TX (PRIM_RX=0, CE=1 for more than 10 us) (130us)
-//    - clear IRQ by writing 1 to STATUS register RX_DR bit. (SPI transaction)
-//    - set CE=0 so we return to Standby when finished transmitting
-//    - set PRIM_RX=1 (SPI transaction).  can we only do this from standby? (130us)
-// - When USART interrupt,
-//    - enter standby (CE=0)
-//    - put token in TX fifo 
-//    - enter TX (PRIM_RX=0, CE=1 for more than 10 us)
-//    - set CE=0 so we return to Standby when finished transmitting
-//    - set PRIM_RX=1 (SPI transaction) to enter RX can we only do this from standby? (130us)
-
-//experiments
-// RF_SETUP, RF_DR_LOW, RF_DR_HIGH.  Default RF data rate is 250kbps ( 4 us per byte ).  
-// It can also be 1 Mbps (1 us per byte) and 2 Mbps (.5 us per byte)
-// increase SPI rate.  right now its running at clkper/128 = sysclk/128 = 250 kHz (4 us per byte)
-
-
 void rx_from_standby(){
-   //enter standby so we can write to configuration register.
-   PORTC.OUTCLR = CE_BM; 
-   _delay_us(10); //should be 10?
-   //enter RX mode: set PRIM_RX = 1
-   tempval = read_register(CONFIG);
-   write_register(CONFIG, tempval | PRIM_RX)
+   //call this from standby to enter rx mode
+   //tempval = read_register(CONFIG);
+   //write_register(CONFIG, tempval | PRIM_RX);
+   write_register(CONFIG, 0x13); //replaces the spi read, but doesn't really speed things up much...
    //set CE for at least 10 us 
    PORTC.OUTSET = CE_BM;
-   _delay_us(10); //should be 10?
+   //_delay_us(ce_delay_us); //is this necessary?
    //wait for pll to settle
    _delay_us(pll_delay_us);
 }
@@ -200,9 +154,9 @@ void setup(){
    SPIC.INTCTRL = SPI_INTLVL_OFF_gc;
    PORTC.DIRSET = PIN5_bm | PIN7_bm; //mosi and sck as outputs
    PORTC.OUTSET = SS_BM; //SS high   
-
    _delay_ms(5); //warm up
 
+   //nrf config
    //turn off auto-retransmit
    write_register(SETUP_RETR,0);
    //turn off disable auto-acknowledge
@@ -229,76 +183,83 @@ void setup(){
    _delay_ms(1);  //give time to start up 
    // and mask MAX_RT interrupts on IRQ
    tempval = read_register(CONFIG);
-   write_register(CONFIG,tempval | MAX_RT)
+   write_register(CONFIG,tempval | MAX_RT);
    //clear all interrupts
    tempval = read_register(STATUS);
-   write_register(STATUS,tempval | MAX_RT | RX_DR | TX_DS)
+   write_register(STATUS,tempval | MAX_RT | RX_DR | TX_DS);
    _delay_ms(1);
 
    sei();
-   rx_from_standby();
+   //enter standby so we can write to configuration register.
+   PORTC.OUTCLR = CE_BM; 
+   _delay_us(ce_delay_us);
+   rx_from_standby(); //enter rx mode
 }
 
-void send_token(){
-   //transition from RX to standby1 (CE=0)
-   PORTC.OUTCLR = CE_BM;   
-   _delay_us(10);
 
+
+void send_token(){
+   //call this from standby1
    //put token in tx fifo
    PORTC.OUTCLR = SS_BM; //SS low
    _delay_us(1);           
    SPIC.DATA = W_TX_PAYLOAD; while(!(SPIC.STATUS & SPI_IF_bm)) {};
-   SPIC.DATA = token; while(!(SPIC.STATUS & SPI_IF_bm)) {};
+   tempval = SPIC.DATA; //get status while we have it
+   SPIC.DATA = 0; while(!(SPIC.STATUS & SPI_IF_bm)) {};
    PORTC.OUTSET = SS_BM; //SS high
    _delay_us(1); 
 
-   tempval = read_register(CONFIG);
-   write_register(CONFIG, tempval & (~PRIM_RX))
-   //pulse CE for at least 10 us 
-   PORTC.OUTSET = CE_BM; _delay_us(10); PORTC.OUTCLR = CE_BM;
+   //tempval = read_register(CONFIG);
+   write_register(CONFIG, tempval & (~PRIM_RX));
+   //pulse CE 
+   PORTC.OUTSET = CE_BM; _delay_us(ce_delay_us); PORTC.OUTCLR = CE_BM;
    //wait for pll to settle
    _delay_us(pll_delay_us);
    //wait until transmit complete
    while( PORTC.IN & IRQ_BM ){}
    //clear IRQ -- need to be in standby.
    tempval = read_register(STATUS);
-   write_register(STATUS, tempval | TX_DS)
+   write_register(STATUS, tempval | TX_DS);
+   //enter standby so we can write to configuration register.
    rx_from_standby(); //return to RX mode
 }
 
 void read_token(){
+   //call this from rx
    //get token from rx fifo
    PORTC.OUTCLR = SS_BM; //SS low
    _delay_us(1);           
    SPIC.DATA = R_RX_PAYLOAD; while(!(SPIC.STATUS & SPI_IF_bm)) {};
-   SPIC.DATA = 0; while(!(SPIC.STATUS & SPI_IF_bm)) {};
+   tempval = SPIC.DATA; //get status while we have it
+   SPIC.DATA = 0; while(!(SPIC.STATUS & SPI_IF_bm)) {}; 
    token = SPIC.DATA;
    PORTC.OUTSET = SS_BM; //SS high
    _delay_us(1); 
 
    //transition from RX to standby1 (CE=0)
    PORTC.OUTCLR = CE_BM;   
-   _delay_us(10);
+   _delay_us(ce_delay_us);
 
    //clear IRQ
-   tempval = read_register(STATUS);
-   write_register(STATUS, tempval | RX_DR)
+   write_register(STATUS, tempval | RX_DR);
    //check_registers(66);
 }
 
 int main(void) {
    setup();
    while(1){
-      //should be in rx mode here.
       if ( !(PORTC.IN & IRQ_BM)){
          read_token(); //in standby
-         token = 1-token; //transform token
+         token += 1; //increment token
          //check_registers(65);
          send_token();
       }
-      //when we get signal from usart, send a token on nrf
+      //we use a signal on the usart to start the oscillation.
       if (USART_RXBufferData_Available(&USART_data)) {
          USART_RXBuffer_GetByte(&USART_data); //clear usart buffer so we only fire once.
+         //transition from RX to standby1 (CE=0)
+         PORTC.OUTCLR = CE_BM;   
+         _delay_us(ce_delay_us);
          send_token(); 
          //check_registers(64);
       }