MSP430x31x
MIXED SIGNAL MICROCONTROLLERS
SLAS165D − FEBRUARY 1998 − REVISED APRIL 2000
14
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
POST OFFICE BOX 1443
•
HOUSTON, TEXAS 77251−1443
8-Bit Timer/Counter (continued)
Two counter inputs (load, enable) control the counter operation. The load input controls load operations. A
write-access to the counter results in loading the content of the preload-register into the counter. The software
writes or reads the preload-register with all instructions.
The preload-register acts as a buffer and can be written
immediately after the load of the counter is completed. The enable input enables the count operation. When
the enable signal is set to high, the counter will count up each time a positive clock edge is applied to the clock
input of the counter.
Serial protocols, like UART protocol, need start-bit edge-detection to determine, at the receiver, the start of a
data transmission. When this function is activated, the counter starts counting after start-bit condition is
detected. The first signal level is sampled into the RXD input data-latch after completing the first timing interval,
which is programmed into the counter. Two latches used for input and output data (RXD_FF and TXD_FF) are
clocked by the counter after the programmed timing interval has elapsed.
UART
The serial communication is realized by using software and the 8-bit timer/counter hardware. The hardware
supports the output of the serial data stream, bit-by-bit, with the timing determined by the counter. The
software/hardware interface connects the mixed signal controller to external devices, systems, or networks.
peripheral file map
PERIPHERALS WITH WORD ACCESS
Watchdog
Watchdog Timer control
WDTCTL
0120h
PERIPHERALS WITH BYTE ACCESS
EPROM
EPROM control
EPCTL
054h
Crystal buffer
Crystal buffer control
CBCTL
053h
System clock
SCG frequency control
SCG frequency integrator
SCG frequency integrator
SCFQCTL
SCFI1
SCFI0
052h
051h
050h
Timer /Port
Timer/Port enable
Timer/Port data
Timer/Port counter2
Timer/Port counter1
Timer/Port control
TPE
TPD
TPCNT2
TPCNT1
TPCTL
04Fh
04Eh
04Dh
04Ch
04Bh
8-Bit Timer/Counter
8-Bit Timer/Counter data
8-Bit Timer/Counter preload
8-Bit Timer/Counter control
TCDAT
TCPLD
TCCTL
044h
043h
042h
Basic Timer1
Basic Timer/Counter2
Basic Timer/Counter1
Basic Timer control
BTCNT2
BTCNT1
BTCTL
047h
046h
040h
LCD
LCD memory 15
:
LCD memory1
LCD control & mode
LCDM15
LCDM1
LCDCTL
03Fh
031h
030h
Port P0
Port P0 interrupt enable
Port P0 interrupt edge select
Port P0 interrupt flag
Port P0 direction
Port P0 output
Port P0 input
P0IE
P0IES
P0IFG
P0DIR
P0OUT
P0IN
015h
014h
013h
012h
011h
010h
Special function
SFR interrupt flag2
SFR interrupt flag1
SFR interrupt enable2
SFR interrupt enable1
IFG2
IFG1
IE2
IE1
003h
002h
001h
000h
