Does anyone know if there is an MSP430 that has a battery backup input for the onboard RTC and Static RAM? If not is there going to be one in the near future?
nope jujst keep the voltage above the ram requirements (usually 1.8v).. The msps are so low in power that you usually just brindge in a voltage source with a diode (the ideal diodes from linear are great.. look at the ltc4413 as an example
Andrew Harwood: Does anyone know if there is an MSP430 that has a battery backup input for the onboard RTC and Static RAM? If not is there going to be one in the near future?
You would need an external battery-backup supervisor. I am going to recommend you TPS3613-01 part. This part allows you to put your 2 AA battery and the VOUT will track the input battery until it goes below Vsense and it will switch over to your backup battery.
The Vsense is an external voltage divider that the customer would need to design and it should be designed to meet the specification of VCC vs MCLK of the MSP430.
If both the main and backup batteries goes below 1.6V, the supervisor will shut-down completely.
Please also see this link for a battery backup circuit that some of our customers have used with the MSP430. It has a battery (BT1) and a regular line power (+3V3).
Regards,Brandon
DCAT - MSP430 ApplicationsTexas Instruments
Andrew,
The first MSP430 device with a backup battery input for RTC will be in the F66xx family (sampled in May 2010).
The battery backup system provides the possibility to operate a real-time clock (RTC_A) together with retaining some (very limited) bytes in a backup RAM and with monitoring some input pins from a backup source when the primary supply fails. Regards, Priya
The battery backup system provides the possibility to operate a real-time clock (RTC_A) together with retaining some (very limited) bytes in a backup RAM and with monitoring some input pins from a backup source when the primary supply fails.
Regards,
Priya
Hi Priya,
I am finding hard to interface RTC rx8025 using I2C on MSP430F2274 please take a look at my posts if u have time please help me
Priya,
Can you tell me how much battery backed up SRAM will be available? We need about 48 bytes.
Kind Regards,
Andrew.
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