UNO-3074 User Manual 242.7 Onboard Isolated Counter/TimerThe UNO-3074 uses one 82C54 programmable timer/counter chip thatincludes three independent 16-bit down counters: counter 0, counter 1 andcounter 2. Counter 0 and counter 1 are for users, and counter 2 is specifiedfor the system and can’t be used by user. Each counter has clock input, gateinput and pulse output. They can be programmed to count from 2 up to65535 or cascaded into one 32-bit counter.The UNO-3074 has two isolated counter input channels designated DI1and DI3 with two isolated output channels designated DO2 and DO3.Therefore, you can set each counter of 82C54 as counter function or timerfunction.2.7.1 Counter/Timer Control RegisterThe Counter/Timer Control Register controls the function and status ofeach counter/timer signal source. Table 2.11 shows the bit map of theCounter/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 MapBaseAddress7 6 5 4 3 2 1 0207H R/W Interrupt Flag/Clear RegisterCTR1F CTR0F208H R/W 82C54 Chip Counter0 Register209H R/W 82C54 Chip Counter1 Register20BH R/W 82C54 Chip Control Register20CH R/W Counter0 Start Control / Output Status RegisterCTR0OutCTR0Gate20DH R/W Counter1 Start Control / Output Status RegisterCTR1OutCTR1Gate20EH R/W Counter0 Setting RegisterCTR0IntSetCTR0OutSetCTR0GateSetCTR0CLKSet20FH R/W Counter1 Setting RegisterCTR32SetS1 S0 CTR1IntSetCTR1OutSetCTR1GateSetCTR1CLKSet
