Omega DAQP-208, 208H, 308 user manual

5.2.9 Auxiliary Control Register (base + 15)

This register configures the operation of A/D, D/A and the timer counter. It is 8-bit wide and write only. Bit 7 picks between TTL and analog trigger source. Bit 6 sets the pre-trigger option. Bit 5 is for the timer/counter interrupt control. Bits 3 and 4 determine the timer/counter operation modes while bit 2 selects the timer/counter clock source. Bits 1 and 0 specify the D/A update modes.

Table 5-21. Auxiliary Control Register Bit Definition

Bit	Function		Explanation
7	External trigger source	0 selects TTL trigger
		1 selects analog trigger
6	Pre-trigger option	1 = with pre-trigger, 0 = without
5	Timer/Counter interrupt	1 = Enabled, 0 = Disabled
	Clear overflow event latch	by writing ‘0’ into this bit
4,3	Timer/Counter mode	00	= Reload
		01	= Pause
		10 = Go
		11 = Go/Pause by external gate signal
2	Timer/Counter clock source	1 = External, 0 = Internal (1 MHz)
1,0	D/A update mode	00	= Direct update
		01 = When timer/counter overflows
		10	= When ext. gate goes low to high
		11	= When pacer clock fires

5.2.10 Auxiliary Status Register (base + 15)

Bits 0-3 and bit 7 in this register are structured so that these bits can be referenced without the associated side effect of “clear after read” on latched events. The “clear after read” side effect is preserved for the status register (base + 2). Bits 0 and 1 are the data FIFO flags. Bit 2 is the data lost event latch. These three bits are defined exactly the same as in the status register.

Bit 3 in this register is the logic “OR” of the two event latches in the status register, (EOS event latch and data FIFO event latch). This bit is “1” if either the EOS or FIFO event is latched. It is “0” if both the EOS and FIFO events are cleared by power up, reset or reading the status register. Table 5-22 lists the bit definition.

DAQP-208/208H/308 Users Manual 57