Microsoft UNO-3074 user manual Onboard Isolated Counter/Timer, Counter/Timer Control Register

2.7 Onboard Isolated Counter/Timer

The UNO-3074 uses one 82C54 programmable timer/counter chip that includes three independent 16-bit down counters: counter 0, counter 1 and counter 2. Counter 0 and counter 1 are for users, and counter 2 is specified for the system and can’t be used by user. Each counter has clock input, gate input and pulse output. They can be programmed to count from 2 up to 65535 or cascaded into one 32-bit counter.

The UNO-3074 has two isolated counter input channels designated DI1 and DI3 with two isolated output channels designated DO2 and DO3. Therefore, you can set each counter of 82C54 as counter function or timer function.

2.7.1 Counter/Timer Control Register

The Counter/Timer Control Register controls the function and status of each counter/timer signal source. Table 2.11 shows the bit map of the Counter/Timer Control Register. The register is readable/writable register. While being written, it is used as a control register; and while being read, it is used as a status register.

Table 2.11: Counter/Timer Control Register Bit Map

Base		7	6	5	4	3	2	1	0
Address
207H	R/W	Interrupt	Flag/Clear Register
						CTR1F	CTR0F
208H	R/W	82C54	Chip Counter0 Register
209H	R/W	82C54	Chip Counter1 Register
20BH	R/W	82C54	Chip Control Register
20CH	R/W	Counter0	Start	Control /	Output Status Register
					CTR0				CTR0
					Out				Gate
20DH	R/W	Counter1	Start	Control /	Output Status Register
					CTR1				CTR1
					Out				Gate
20EH	R/W	Counter0	Setting	Register
						CTR0	CTR0	CTR0	CTR0
						IntSet	OutSet	GateSet	CLKSet
20FH	R/W	Counter1	Setting	Register
			CTR3	S1	S0	CTR1	CTR1	CTR1	CTR1
			2Set			IntSet	OutSet	GateSet	CLKSet

UNO-3074 User Manual 24