Issue 133 August 2001
MSP430 News Flash:

Recognizing the Flexibility of Reprogramming

Start • MSP430F1121 • Comparatively Speaking • Battery Monitor • Dynamic Inputs • RC To The Rescue • E(OR I)IN • It's Only The Beginning • Sources & PDF

MSP430F1121
I don’t want to rehash Tom Cantrell’s excellent introduction of TI’s MSP430 devices in “Sweet Sixteen” (Circuit Cellar 126), so I’ll refer you to his Silicon Update for all the specifics. However, let’s review a few of the high points. With 4 KB of flash memory and 256 bytes of RAM, this isn’t your minimalist low-end chunk of silicon. Just look at the block diagram in Figure 1 to see the rest of the F1121’s internal organs. This 16-bit CPU was designed for battery use with a low voltage requirement of 1.8–3.6 V and a nominal current consumption of < 1 mA at 8 MHz. The use of slower clock speeds and/or low power modes can reduce that intake significantly (to microamps).

(click here to enlarge)

Figure 1—The 16-bit RISC core of the MSP430F1121 has a cycle time equal to MCLK. It boasts low-voltage operation, low current consumption, fast wake up from sleep, OTP/flash memory devices, and JTAG interface.

One of the most significant performance benefits is the ability to wake up from standby in only 6 µs when using the internal digitally controlled oscillator (DCO). Although the DCOCLK is sensitive to both voltage and temperature, it is great for those minimum component applications where the actual operating frequency doesn’t need to be dead nuts. The standard external crystal and oscillator inputs can also be used when an accurate time base is necessary. In fact, you can switch between time bases through software.