Intel 8XC196NP, 80C196NU manual EPA Channel Functional Overview, Quadrature Mode Timing and Count

8XC196NP, 80C196NU USER’S MANUAL

CLKOUT

PH2

TxCLK

TxDIR

COUNT

x

x + 1

x + 2

x + 3

x + 4

x

+ 5

x + 6

x + 5

x + 4

x + 3

x + 2

x + 1

A0269-02

Figure 10-4. Quadrature Mode Timing and Count

10.4 EPA CHANNEL FUNCTIONAL OVERVIEW

The EPA has four programmable capture/compare channels that can perform the following tasks.

•capture the current timer value when a specified transition occurs on the EPA pin

•clear, set, or toggle the EPA pin when the timer value matches the programmed value in the event-time register

•generate an interrupt when a capture or compare event occurs

•generate an interrupt when a capture overrun occurs

•reset its own base timer in compare mode

•reset the opposite timer in both compare and capture mode

Each EPA channel has a control register, EPAx_CON (capture/compare channel); an event-time register, EPAx_TIME (capture/compare channel); and a timer input (Figure 10-5). The control register selects the timer, the mode, and either the event to be captured or the event that is to occur. The event-time register holds the captured timer value in capture mode and the event time in com- pare mode. See “Programming the Capture/Compare Channels” on page 10-18 for configuration information.

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