Decoding part numbers

What does something like MSP430F1121 mean?

The letter indicates the type of ROM on board:

• C - Mask ROM. This is programmed at manufacturing time.

• E - UV-EPROM. This comes in a windowed package and is erasable with UV. This requires a special high voltage supply to program.

• F - Flash ROM. This is electrically erasable, and can be programmed with normal operating voltages.

• P - One-time programmable. This is an E part in a cheaper windowless package. Once programmed, it cannot be erased.

Note that only the original 3xx series parts use UV-EPROM. Everything after that uses Flash ROM. Programming the EPROM parts is done over the JTAG port.

The first digit after the letter is the overall family: 1, 3 or 4. They are roughly in increasing order of capability, but there's a lot of range. Parts are generally upward-compatible within a family.

Basically, 1xx parts don't have an LCD controller, while all the 3xx parts do. Both families have models with ADCs; the 11x2 parts have a 10-bit ADC, while others have a 12-bit ADC. Some parts have hardware UARTS, although any of them can bit-bang it.

Initially, the 1xx parts were small 20- and 28-pin parts, and the 3xx parts were 56 or 64 pins. However, the 1xx parts have grown up and the 13x and higher packages come in 64-pin packages, while the 3xx parts range from a 48-pin 31xS subset to 100 pins.

The second digit is the device within a family. Again, generally higher numbers are more capable, but it varies a lot. As a general overview:

• 11x: 20-pin parts. 11x1 adds comparator, 11x2 adds ADC10.

• 12x: 28-pin parts, like 11x1 but with more I/O and USART.

• 13x: 64-pin parts, adding lots more I/O, another timer, USART, and ADC12.

• 14x: 64-pin parts, like 13x but with a hardware multiplier and a second USART.

• 15x: Like 13x, but adding 2xDAC12, 3xDMA, brownout reset and I2C.

• 16x: Like 14x, but adding 2xDAC12, 3xDMA, brownout reset and I2C.

• 31x: 56 pins, basic device with I/O, timers, comparator/timer, LCD driver.

• 32x: 64 pins, like 31x but with ADC12+2 (can be kludged to do 14 bits).

• 33x: 100 pins, like 31x with more I/O and LCD, multiplier, and USART.

• 41x: 64 pins, basic device with I/O, timers, comparator, LCD driver.

• 43x: 80 or 100 pins, more LCD, ADC12, second timer, USART, second crystal oscillator.

• 44x: 100 pins, like 43x but with a hardware multiplier, second USART and expanded timer.

A fourth digit, if present, is a sub-version number. A '1121 is a '112 with a little bit extra (an analog comparator for software ADC). A '1122 is a '112 with a 10-bit ADC. (Exception: the 161x parts.)

The third digit encodes the amount of memory on the chip:

• xx0: 1K ROM, 128 RAM

• xx1: 2K ROM, 128 RAM

• xx2: 4K ROM, 256 RAM

• xx3: 8K ROM, 256 RAM

• xx4: 12K ROM, 512 RAM

• xx5: 16K ROM, 512 RAM

• xx6: 24K ROM, 1024 RAM

• xx7: 32K ROM, 1024 RAM

• xx8: 48K ROM, 2048 RAM

• xx9: 60K ROM, 2048 RAM

The 16x series adds:

• xx10: 32K ROM, 5K RAM

• xx11: 48K ROM, 10K RAM

Note the 161x numbers are an exception to the usual 4th digit rule.