CPC700 User’s Manual—Preliminary
9-3
9.2.2 Capture Timers
Each of the five capture timers (GPTCAPT0-4) is 32 bits wide and captures the TBC value whenever a
capture event is generated via the GPT Capture Event Generation register (CPRCAPTEVNT) and the cor-
responding enable bit is set (1) in the GPT Capture Enable (GPTCE) register. If the corresponding GPT
Interrupt Mask (GPTIM) bit is disabled (0), the event’s interrupt status bit will be set in the GPT Interrupt
Status (GPTIS) register. Further, if the corresponding GPT Interrupt Enable (GPTIE) register bit is set (1),
the interrupt will be sent to the CPC700 interrupt controller. If enabled in the CPC700 interrupt controller,
the capture event can be used to interrupt the processor. See Figure 48 for the Capture Timers Logic/Block
Diagram.
Figure 48. Capture Timers Logic/Block Diagram
Note that the CPRCAPTEVNT register is implemented in the Clock, Power Management, and Reset (CPR)
logic of the CPC700. The bits in the CPRCAPTEVNT register can be made falling-edge active (set to 0 to
trigger) or rising-edge active (set to 1 to trigger) via the GPT Edge Detection Control (GPTEC) register.
Refer to Section 6.5.3, “GPT Capture Event Generation Register (CPRCAPTEVNT)” for details.
9.2.2.1 Capture Timers Interrupt
The following steps must happen for a capture timer interrupt to occur:
• If needed, the corresponding bit should be programmed in the GPTSC register to determine if the GPT
capture events in the CPRCAPTEVNT register are synchronized to the TBC clock source.
• If needed, the corresponding bit should be programmed in the GPTEC register to determine if the GPT
capture events in the CPRCAPTEVNT register are rising-edge or falling-edge active.
• The corresponding enable bit must be set (1) in the GPT Capture Enable (GPTCE) Register.
Time Base Counter (TBC)
Interrupt Mask (GPTIM)
Interrupt Enable (GPTIE)
Interrupt Status (GPTIS)
Capture Int.
(1/5) to
Int. Controller
Capture
Event
(1/5)
Sel
Sync Control (GPTSC)
TBCclk
Sync
Sel
Edge Control (GPTEC)
Fall
Detect
Rise
Detect
Capture Register (CAPTx)
Capture Enable (GPTCE)
Capture
Valid (1/5)
(CPRCAPTEVNT)
Содержание CPC700
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