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
Receive timing error consists of two error sources. The first is the bit-to-bit timing error similar to the transmit bit timing error. The second is the error between a start edge occurring and the start edge being accepted by the USCI module. Figure 15-11 shows the asynchronous timing errors between data on the UCAxRXD pin and the internal baud-rate clock. This results in an additional synchronization error. The synchronization error tSYNC is between -0.5 BRCLKs and +0.5 BRCLKs independent of the selected baud rate generation mode.
The ideal sampling time is in the middle of a bit period:
The real sampling time is equal to the sum of all previous bits according to the formulas shown in the transmit timing section, plus one half BITCLK for the current bit i, plus the synchronization error tSYNC.
This results in the following for the low-frequency baud rate mode:
Where,
mUCBRSx[i] = Modulation of bit i from Table 15-2
For the oversampling baud rate mode the sampling time of bit i is calculated by:
Where,
= Sum of ones from columns 0 - from the corresponding row in Table 15-3
mUCBRSx[i] = Modulation of bit i from Table 15-2
This results in an error normalized to one ideal bit time (1 / baud rate) according to the following formula:
ErrorRX[i] = (tbit,RX[i] − tbit,ideal,RX[i]) × baud rate × 100%