XR17V352IB-0A-EVB Datasheet, PDF (20/64 Pages) Exar Corporation – HIGH PERFORMANCE DUAL PCI EXPRESS UART

XR17V352
HIGH PERFORMANCE DUAL PCI EXPRESS UART
REV. 1.0.4
16-Bit Timer/Counter Programmable Registers
TIMERMSB Register
TIMERLSB Register
Bit-15 Bit-14 Bit-13 Bit-12 Bit-11 Bit-10 Bit-9 Bit-8
Bit-7 Bit-6 Bit-5 Bit-4 Bit-3 Bit-2 Bit-1 Bit-0
REGA [15:8] Register
Reserved.
TIMERCNTL [7:0] Register
The bits [3:0] of this register are used to issue commands. The commands are self-clearing, so reading this
register does not show the last written command. Reading this register returns a value of 0x01 when the Timer
interrupt is enabled and there is a pending Timer interrupt. It returns a value of 0x00 at all other times. The
default settings of the Timer, upon power-up, a hardware reset or upon the issue of a ’Timer Reset’ command
are:
■ Timer Interrupt Disabled
■ Re-triggerable mode selected
■ Internal 125 MHz clock selected as clock source
■ Timer output not routed to MPIO[0]
■ Timer stopped
TABLE 9: TIMER CONTROL REGISTERS
TIMERCNTL [7:4] Reserved
TIMERCNTL [3:0]
These bits are used to invoke a series of commands that control the function of the Timer/Counter.
The commands 1100 to 1111 are reserved.
0001: Enable Timer Interrupt
0010: Disable Timer Interrupt
0011: Select One-shot mode
0100: Select Re-triggerable mode
0101: Select Internal 125 MHz clock as clock input for the Timer
0110: Select External Clock input through the TMRCK pin for the Timer
0111: Route Timer output to MPIO[0] pin
1000: De-route Timer output from MPIO[0]
1001: Start Timer
1010: Stop Timer
1011: Reset Timer
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