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AUXVCC3 voltage level for RTC_C in MSP430F6779

Other Parts Discussed in Thread: MSP430F6779, MSPWARE, MSP430F6779A, MSP-TS430PEU128

Hello,

I am in dilemma that whether there is requirement for AUXVCC3 power supply for the RTC_C module even if my board is working on continuous power supply. 

1) Currently I have DVCC=3.3 V , can I connect DVCC with AUXVCC3 (pin) directly to it so that RTC_C can be run?

2) Or should I just leave it unconnected ? Because board is working on continuous power supply.

3) And if it has to connect with supply voltage, how much voltage can I able to provide (max)?

Thank you.

Abhi

  • Hi,

    I was trying to run RTC module of MSP430F6779 using MSPware example code but during debugging I came to know that my pointer is not going into RTC ISR.

    In code, All required initialization for RTC has been done.

    One doubt is, my AuxVCC3 pin is open and not connect with external battery.

    Is it must to connect external supply for RTC module in MSP430F6779?

    waiting for your reply.

    Thanks

  • Hello,

    I have customized board of MSP430F6779, I have currently no provision for alternate power supply for the AUXVCC3.

    I want to utilize the DVCC for the said supply. By reading the user guide I found that Charger can be enable by setting AUXCHEN in the AUX3CHCTL register. But, I found that the voltage at the Pin 29(AUXVCC3) is very low about 0.3V. 

    So can anyone tell me what should I do so that I can use RTC_C module for MSP430F6779? 

    Thank you.

    Regards,

    Abhi Pandya

  • Hello,

    I have initialize the RTC_C registers with following code also put some control bits in the Registers. But when I run this code it would not get entered into ISR.
    Ultimately RTCSEC RTCMIN,etc. registers are not updated with time pass.


    { //some code // Enable XT1 AUX3CHCTL = AUXCHKEY + AUXCHEN + AUXCHC_1 + AUXCHV_1; // Configure RTC_C RTCCTL0_H = RTCKEY_H; // Unlock RTC_C module RTCCTL0_L |= RTCTEVIE | RTCAIE | RTCRDYIE; // Enable RTC time event, alarm event, RTCCTL1 |= RTCBCD | RTCHOLD; // RTC enable BCD mode, RTC hold //Initilize RTC_C registers RTCCTL1 &= ~(RTCHOLD); // Start RTC calendar mode RTCCTL0_H = 0; // Lock RTC_C module __bis_SR_register(GIE); while(1); } // RTC Interrupt Service Routine #if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__) #pragma vector=RTC_VECTOR __interrupt void rtc_isr(void) #elif defined(__GNUC__) void __attribute__ ((interrupt(RTC_VECTOR))) rtc_isr (void) #else #error Compiler not supported! #endif { switch (__even_in_range(RTCIV, 16)) { case RTCIV_NONE: // No interrupts break; case RTCIV_RTCOFIFG: // RTCOFIFG break; case RTCIV_RTCRDYIFG: // RTCRDYIFG { P1OUT ^= 0x01; // Toggles P1.0 every second //volatile int sec=RTCSEC; } break; case RTCIV_RTCTEVIFG: // RTCEVIFG __no_operation(); // Interrupts every minute break; case RTCIV_RTCAIFG: // RTCAIFG __no_operation(); // Interrupts every alarm event break; case RTCIV_RT0PSIFG: // RT0PSIFG break; case RTCIV_RT1PSIFG: // RT1PSIFG break; // case 14: break; // Reserved case 16: break; // Reserved default: break; } }

    What should be the cause for it? Can anyone resolve this issue?

    Thank you.

    Regards,

    Abhi

  • Hello Abhi,

    Here's a quote from Section 4.1 of the MSP430F6xx User's Guide: "If AUXVCC3 is not powered by a dedicated supply, it can either be connected to DVCC externally or powered by enabling the AUXVCC3 charger. If powered by the charger, the recommended capacitor should be connected externally. If AUXVCC3 is not powered or connected to DVSS, the backup subsystem (including, for example, the 32-kHz crystal oscillator) is not functional."

    So to answer your question, you should connect DVCC to AUXVCC3 directly. The maximum supply voltage that can be used is 3.6 V.

    Regards,
    Ryan
  • Merging these threads due tot he fact they are about the same subject and most likely stem from the same issue. Please see Ryan's statement above about connecting AUXVCC3. Also please see the following post and the following TI Design that should provide examples of different AUXVCC settings and using RTC_C.

    e2e.ti.com/.../1547717

    www.ti.com/.../TIDM-AUX-MODULE

    Regards,

    JH
  • Thank you all.

    I have included recommended capacitor between AUXVCC3 and GND. I have even enable built-in charger by setting AUXCHEN. But, when I measure the voltage at the contact of Pin 29, it is showing 0.3V. 

    1) So do I have to connect the DVCC to AUXVCC3 externally?

    2) Is it because that I am unable to read registers? 

    Regards,

    Abhi

  • Abhi,

    Can you provide your register settings here for the AUX module? You can power AUXVCC3 through the charger circuit from DVCC. Please see section 4.2.10 of the User guide for more information of how to set this up. Please also see the note in section 4.1 that gives additional information about AUXVCC3. Because this configuration connects AUXVCC3 internally to DVCC (via charger), when power to DVCC is lost, so is power to AUXVCC3.

    Regards,
    JH
  • Hi Jace,

    AUX3CHCTL = AUXCHKEY + AUXCHEN + AUXCHC_1 + AUXCHV_1;

    I have included this line in my code before initialize RTC registers. Also when look at the note provided in the Section 4.1 it tells you " If AUXVCC3 is not powered by a dedicated supply, it can either be connected to DVCC externally or powered by enabling the AUXVCC3 charger. If powered by the charger, the recommended capacitor should be connected externally."

    So, I have connected the recommended capacitor which is provided in device datasheet. But it still problem lays.

    Please anyone could help me out.

    Regards,

    Abhi

  • Hi,

    Anyone who has knowledge to resolve this issue, please provide the insight on this. I am in bit of urgency.

    Thank you.

    Regards,

    Abhi

  • Hello Abhi,

    I just ran a test using code example msp430f677xA_rtc_01.c, a MSP-TS430PEU128 target board, and a MSP430F6779A device. JP13 was placed in the 3-4 position so that AUXVCC3 was not connected to DVcc and therefore had to be powered by the charger for proper operation. The test worked as expected and I was able to measure an average voltage of 2.8 V on the AUXVCC3 pin. A 470 nF capacitor is connected externally.

    If you can run this test code on your end and still receive the same error then something is either at fault with your custom board design or MSP430F6779 device. Have you tried testing with different devices? Can you confirm that your AUXVCC3 pin is not somehow shorted to GND or another pin?

    Regards,
    Ryan
  • Hello Ryan,

    Thank you for your insight on this matter. 

    But, I would want one more favor from you. As you know we have customized target board particularly for MSP430F6779A-PZ package. Also we are unable to open the .sch file on the TI website, so can you provide me the another formats like .dsn or the file that can be read by Orcad.

    Waiting for your positive reply.

    Regards,

    Abhi.

  • Hello Abhi,

    Can you please link to the specific .sch file you are referring to? At any rate this is a hard request to fulfill as TI only uses Altium for their schematics/board designs and cannot provide any other formats such as .dsn for Orcad. I know that tools/plugins exist for converting Orcad documents to Altium but I do not know if the same can be said for the opposite case. You will have to investigate this matter further or recreate the .sch file in Orcad manually.

    Regards,
    Ryan

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