LPM3 sleep

[rolotumazi]

Hi,

i'm trying to get the example "ping-remote-led-every500ms-using-vlo.c" running on a g2452 and i need some help please.

i've managed to get a pair of g2553's running the "ike-uscia-rx.c" and "ike-uscia-tx.c" examples. i thought a good test would be to run "ping-remote-led-every500ms-using-vlo.c" on a g2452 alongside "ike-uscia-rx.c" on a g2553. the LEDs would give me some visual feedback as to what is and isn't going on. below is the adapted "ping-remote-led-every500ms-using-vlo.c" example that i expected would work. i thought the problem could also be that my "nrf_userconfig.h" or "msprf24.c" file may need adjustments but i've not been able to establish this. any help would be greatly appreciated!

#include <msp430.h>
#include <string.h>
#include "msprf24.h"
#include "nrf_userconfig.h"

volatile unsigned int user;
volatile int wdtsleep;

/* Sleep for <cycles> * 47ms */
void wdt_sleep(unsigned int cycles)
{
        wdtsleep = cycles;
        WDTCTL = WDTPW | WDTTMSEL | WDTCNTCL | WDTSSEL | WDTIS1;  // WDT interval = 512 VLOCLK cycles, about 47ms
        IFG1 &= ~WDTIFG;
        IE1 |= WDTIE;
        LPM3;
        WDTCTL = WDTPW | WDTHOLD;
}

// WDT overflow/STOP
#pragma vector=WDT_VECTOR
__interrupt void WDT_ISR(void)
{
        if (wdtsleep) {
                wdtsleep--;
        } else {
                IFG1 &= ~WDTIFG;
                IE1 &= ~WDTIE;
                __bic_SR_register_on_exit(LPM3_bits);
        }
}

void main()
{
    P1DIR |= BIT0;
    P1OUT |= BIT0;
    char addr[5];
    char buf[32];

    WDTCTL = WDTHOLD | WDTPW;
    DCOCTL = CALDCO_16MHZ;
    BCSCTL1 = CALBC1_16MHZ;
    BCSCTL2 = DIVS_2;  // SMCLK = DCOCLK/4
        BCSCTL3 = LFXT1S_2;  // ACLK = VLOCLK/1
        BCSCTL3 &= ~(XT2OF|LFXT1OF);

    wdtsleep = 0;

    // SPI (USI) uses SMCLK, prefer SMCLK=DCO (no clock division)
    user = 0xFE;

    /* Initial values for nRF24L01+ library config variables */
    rf_crc = RF24_EN_CRC | RF24_CRCO; // CRC enabled, 16-bit
    rf_addr_width      = 5;
    rf_speed_power     = RF24_SPEED_1MBPS | RF24_POWER_0DBM;
    rf_channel         = 120;

    msprf24_init();  // All RX pipes closed by default
    msprf24_set_pipe_packetsize(0, 32);
    msprf24_open_pipe(0, 1);  // Open pipe#0 with Enhanced ShockBurst enabled for receiving Auto-ACKs

    // Transmit to 0xDEADBEEF01
    msprf24_standby();
    user = msprf24_current_state();
    addr[0] = 'r'; addr[1] = 'a'; addr[2] = 'd'; addr[3] = '0'; addr[4] = '1';
    memcpy(addr, "\xDE\xAD\xBE\xEF\x01", 5);
    w_tx_addr(addr);
    w_rx_addr(0, addr);  // Pipe 0 receives auto-ack's, autoacks are sent back to the TX addr so the PTX node
                 // needs to listen to the TX addr on pipe#0 to receive them.
    buf[0] = '0';
    buf[1] = '0';

    P1OUT &= ~BIT0;

    while(1) {
        P1OUT |= BIT0;
        if (rf_irq & RF24_IRQ_FLAGGED) {  // Just acknowledging previous packet here
            msprf24_get_irq_reason();
            msprf24_irq_clear(RF24_IRQ_MASK);
            user = msprf24_get_last_retransmits();
        } else {  // WDT sleep completed, send a new packet
            if (buf[0] == '1') {
                buf[0] = '0';
                buf[1] = '1';
            }
            else {
                buf[0] = '1';
                buf[1] = '0';
            }
            w_tx_payload(32, buf);
            msprf24_activate_tx();
        }
        P1OUT &= ~BIT0;
        wdt_sleep(10);  // ~500ms LPM3 sleep
    }
}

[spirilis]

Are you sending these packets to the right address? Ike's example listens for 0xDEADBEEF00 but your code here sends to 0xDEADBEEF01.

[rolotumazi]

Yes, i can confirm that i'm sending to and receiving on address 0xDEADBEEF01 using Ike's example. by changing the TX side to "ping-remote-led-every500ms-using-vlo.c" the communication fails. the relevant corresponding code on the Ike's RX i'm using is below. Is there anything specific i need to implement in the "msprf24.c" or "nrf_userconfig.h" files to get "ping-remote-led-every500ms-using-vlo.c" to work? i've only commented out the SPI selection in the "nrf_userconfig.h" file.

//#define RF24_SPI_DRIVER_USCI_A 1
//#define RF24_SPI_DRIVER_USCI_B 1

and here's the piece of code of Ike's RX i'm using with only the address changed.

    /* Initial values for nRF24L01+ library config variables */
    rf_crc = RF24_EN_CRC | RF24_CRCO; // CRC enabled, 16-bit
    rf_addr_width      = 5;
    rf_speed_power     = RF24_SPEED_1MBPS | RF24_POWER_0DBM;
    rf_channel         = 120;

    msprf24_init();
    msprf24_set_pipe_packetsize(0, 32);
    msprf24_open_pipe(0, 1);  // Open pipe#0 with Enhanced ShockBurst

    // Set our RX address
    addr[0] = 0xDE; addr[1] = 0xAD; addr[2] = 0xBE; addr[3] = 0xEF; addr[4] = 0x01;
    w_rx_addr(0, addr);

[spirilis]

Assuming your CE/CSN/IRQ pins on the G2452 example are the same, then no it should "just work".

Can you put an LPM4 after this section:

// Transmit to 0xDEADBEEF01
msprf24_standby();
user = msprf24_current_state();
addr[0] = 'r'; addr[1] = 'a'; addr[2] = 'd'; addr[3] = '0'; addr[4] = '1';
memcpy(addr, "\xDE\xAD\xBE\xEF\x01", 5);
w_tx_addr(addr);

Then run it, stop the program inside the debugger and examine the value of the "user" variable? Curious to see if the library sees your transceiver properly.

I usually do this from mspdebug's command prompt with:

sym find user (this gives you an address in hex) md

2

e.g. md 0x204 2

[rolotumazi]

that was good advice, thank you! it's alive! i forgot that the MISO and MOSI connections needed to be swapped over for the g2452. so if i check on the "user" variable now after stopping the program in the debugger with a "LPM4;" right after

// Transmit to 0xDEADBEEF01
msprf24_standby();
user = msprf24_current_state();
addr[0] = 'r'; addr[1] = 'a'; addr[2] = 'd'; addr[3] = '0'; addr[4] = '1';
memcpy(addr, "\xDE\xAD\xBE\xEF\x01", 5);
w_tx_addr(addr);

i get a value of "2" at address 0x0208 i understand that to mean that the radio is in a state of "RF24_STATE_STANDBY_I" at this point.

i also replaced lines:

addr[0] = 'r'; addr[1] = 'a'; addr[2] = 'd'; addr[3] = '0'; addr[4] = '1';
memcpy(addr, "\xDE\xAD\xBE\xEF\x01", 5);

with:

addr[0] = 0xDE; addr[1] = 0xAD; addr[2] = 0xBE; addr[3] = 0xEF; addr[4] = 0x01;

on both "ping-remote-led-every500ms-using-vlo.c" and Ike's RX and that seemed to have done... well something.

the current consumption is good. i've extended the sleep time to 100 cycles (~ 5 secs) and during this time the power draw is below 30uA.

Thank you very much!

[spirilis]

Good stuff! Glad to hear it's figured out. Yeah I'm not sure why TI decided to go flip-flop the USCI_B pins when they introduced the G2xx3, it's goofy to me especially since it's now their established "standard" per http://processors.wiki.ti.com/index.php/BYOB ...