MSP430F1612 Peripheral Usage For TJ3SAT:
Refer to the Texas Instruments Specification Sheet for MSP430Fx16x for more details.
ACLK/MCLK : set to 1:1 with the 32768 Hz oscillator. Yes, this is slow, but also uses very little power compared to faster speeds
UART0 : communicates at 9600 baud with the Stensat Radio
Timer B is used to supply timeout flag in support of receiving packets from the Stensat Radio
UART1 : communicates at 9600 baud with the DS2480 1-wire bridge
The DS2480 handles all low level, complex communication with 1-wire sensors:
Timer A CCR0: interrupts every second and provides a 1 second 'tick'
Timer A TAIV CCR1/2 : supports (barely) a ~9600 baud software UART to transmit the text string to the payload. Currently any responses from the textspeak are ignored (and not wired). The transmitted digital text is wired to port 1, bit 3 (P1.3). See MSP430Fx61x Specification for more detail.
Watchdog Timer: current version of software (18 JUL 2010) shuts off the WDT. The flight release will strobe the WDT each time through the command loop. The maximum loop time is yet to be determined
No A/D functions are used directly on the MSP430
General Discrete I/O:
- P6.0 (interpret as port 6, bit 0) provides Radio Transmit Enable/Disable
- P1.2 provides Radio Receiver Enable/Disable
- P4.2 is also direct wired to P1.2 and the Radio Receiver as well (result of implementing the StenSat Radio into TJ3SAT with minimal changes)
- P4.6 provides the Enable/Disable for the auxiliary +5VDC Bus. The TextSpeak payload is powered on this bus