For JTAG and SBW connections on both the FR4xx and FR59xx devices, see the MSP430 Hardware Tools User's Guide. Note the parallel capacitor on the pin
RST/NMI/SBWTDIO should be less than 1.1 nF when using SBW for debug or firmware download.
Both the FR4xx and FR59xx devices provide an internal pullup resistor on the reset line, which eliminates the need for an external reset resistor. For details, see the Special Function Register (SFR) (SFRRPCR) in the MSP430FR58xx, MSP430FR59xx, and MSP430FR6xx family user's guide.
Neither the FR4xx nor the FR59xx devices provide internal load capacitors on the LFXT oscillator. External load capacitors are required if the LFXT oscillator is used. For layout, the external crystal must be as close as possible to FR4xx pins XIN and XOUT. The load capacitors must be placed close to crystal pins. The capacitor values must be matched with crystal specification and PCB layout. For more guidance about crystal selection, layout concerns and crystal oscillator testing, see MSP430 32-kHz crystal oscillators.
Compared to the FR59xx family, the FR4xx clock system is quite different. There is an FLL and an internal trimmed REFO in FR4xx devices that can generate a REFO clock at 32.768 kHz with accuracy of ±3.5% in the full temperature range. For detailed information, see Section 7.2.2 and the Clock System chapter of the MSP430FR4xx and MSP430FR2xx family user's guide
The FR231x, FR235x, and FR215x MCUs support a high-frequency clock source on the XT1 oscillator. The FLL reference divider FLLREFDIV is available only when XT1 HF mode is supported in the device. The FR59xx devices do not support a high-frequency clock source on the LFXT oscillator. If a high frequency clock source is used, it must be connected to the secondary crystal oscillator (XT2).
F59xx devices have analog voltage supply pins (AVCC and AVSS) and digital voltage supply pins (DVCC and DVSS). FR4xx devices have only one pair of power supply pins (DVCC and DVSS).
FR235x and FR215x MCUs support –40°C to 105°C operating temperature. –40°C to 105°C system requirement can be matched using the devices.