SLAU144K December 2004 – August 2022 MSP430AFE221 , MSP430AFE222 , MSP430AFE223 , MSP430AFE231 , MSP430AFE232 , MSP430AFE233 , MSP430AFE251 , MSP430AFE252 , MSP430AFE253 , MSP430F2001 , MSP430F2002 , MSP430F2003 , MSP430F2011 , MSP430F2012 , MSP430F2013 , MSP430F2101 , MSP430F2111 , MSP430F2112 , MSP430F2121 , MSP430F2122 , MSP430F2131 , MSP430F2132 , MSP430F2132-EP , MSP430F2232 , MSP430F2234 , MSP430F2252 , MSP430F2252-Q1 , MSP430F2254 , MSP430F2272 , MSP430F2272-Q1 , MSP430F2274 , MSP430F2274-EP , MSP430F233 , MSP430F2330 , MSP430F235 , MSP430F2350 , MSP430F2370 , MSP430F2410 , MSP430F2416 , MSP430F2417 , MSP430F2418 , MSP430F2419 , MSP430F247 , MSP430F2471 , MSP430F248 , MSP430F2481 , MSP430F249 , MSP430F2491 , MSP430F2616 , MSP430F2617 , MSP430F2618 , MSP430F2619 , MSP430G2001 , MSP430G2101 , MSP430G2102 , MSP430G2111 , MSP430G2112 , MSP430G2121 , MSP430G2131 , MSP430G2132 , MSP430G2152 , MSP430G2153 , MSP430G2201 , MSP430G2201-Q1 , MSP430G2202 , MSP430G2203 , MSP430G2210 , MSP430G2211 , MSP430G2212 , MSP430G2213 , MSP430G2221 , MSP430G2230 , MSP430G2231 , MSP430G2231-Q1 , MSP430G2232 , MSP430G2233 , MSP430G2252 , MSP430G2253 , MSP430G2302 , MSP430G2303 , MSP430G2312 , MSP430G2313 , MSP430G2332 , MSP430G2333 , MSP430G2352 , MSP430G2353 , MSP430G2402 , MSP430G2403 , MSP430G2412 , MSP430G2413 , MSP430G2432 , MSP430G2433 , MSP430G2444 , MSP430G2452 , MSP430G2453 , MSP430G2513 , MSP430G2533 , MSP430G2544 , MSP430G2553 , MSP430G2744 , MSP430G2755 , MSP430G2855 , MSP430G2955 , MSP430TCH5E
The status register (SR/R2), used as a source or destination register, can be used in the register mode only addressed with word instructions. The remaining combinations of addressing modes are used to support the constant generator. Figure 3-6 shows the SR bits.
15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Reserved | V | SCG1 | SCG0 | OSC OFF | CPU OFF | GIE | N | Z | C | ||||||
rw-0 | rw-0 | rw-0 | rw-0 | rw-0 | rw-0 | rw-0 | rw-0 | rw-0 | rw-0 |
Table 3-1 describes the status register bits.
Bit | Description | |
---|---|---|
V | Overflow bit. This bit is set when the result of an arithmetic operation overflows the signed-variable range. | |
ADD(.B), ADDC(.B) |
Set when: | |
Positive + Positive = Negative | ||
Negative + Negative = Positive | ||
Otherwise reset | ||
SUB(.B), SUBC(.B), CMP(.B) |
Set when: | |
Positive – Negative = Negative | ||
Negative – Positive = Positive | ||
Otherwise reset | ||
SCG1 | System clock generator 1. When set, turns off the SMCLK. | |
SCG0 | System clock generator 0. When set, turns off the DCO dc generator, if DCOCLK is not used for MCLK or SMCLK. | |
OSCOFF | Oscillator Off. When set, turns off the LFXT1 crystal oscillator, when LFXT1CLK is not use for MCLK or SMCLK. | |
CPUOFF | CPU off. When set, turns off the CPU. | |
GIE | General interrupt enable. When set, enables maskable interrupts. When reset, all maskable interrupts are disabled. | |
N | Negative bit. Set when the result of a byte or word operation is negative and cleared when the result is not negative. | |
Word operation: N is set to the value of bit 15 of the result. | ||
Byte operation: N is set to the value of bit 7 of the result. | ||
Z | Zero bit. Set when the result of a byte or word operation is 0 and cleared when the result is not 0. | |
C | Carry bit. Set when the result of a byte or word operation produced a carry and cleared when no carry occurred. |