PORTIBM PC Portable (uses same BIOS as XT) 0340-0357 - RTCsee Real-Time Clock (1st Real Time Clock for XTIBM PC XT)
		(used by TIMER.COM v1.2 which is the 'standard' timer program)
Range:	alternate at 0240-0257
SeeAlso:  PORTIBM PC Portable (uses same BIOS as XT) 0240h-0257h

0340  RW  0.001 seconds		0-99
0341  RW  0.1 and 0.01 seconds	0-99
0342  RW  seconds		0-59
0343  RW  minutes		0-59
0343  RW  hours			0-23
0345  RW  day of week		1-7
0346  RW  day of month		1-31
0347  RW  month			1-12
0348  RW  RAM(Random Access Memory)	See also DRAM, SRAM. (upper nybble only)
0349  RW  year			0-99
034A  RW  RAM(Random Access Memory)	See also DRAM, SRAM. last month storage
034B  RW  RAM(Random Access Memory)	See also DRAM, SRAM. year storage (-80)
034C  RW  RAM(Random Access Memory)	See also DRAM, SRAM. reserved
034D  RW  RAM(Random Access Memory)	See also DRAM, SRAM. not used
034E  RW  RAM(Random Access Memory)	See also DRAM, SRAM. not used
034F  RW  RAM(Random Access Memory)	See also DRAM, SRAM. not used
0350  R-  interrupt status register
0351  -W  interrupt control register
0352  -W  counter reset
0353  -W  RAM(Random Access Memory)	See also DRAM, SRAM. reset
0354  R-  status bit
0355  -W  GO command
0356  ??  standby interrupt
0357  ??  test mode