9-4
General Purpose Timers
• The corresponding Interrupt Mask bit must be reset (0) in the GPT Interrupt Mask (GPTIM) Register.
• The corresponding Interrupt Enable bit must be set (1) in the GPT Interrupt Enable (GPTIE) Register.
• The corresponding capture event must occur (set via the CPRCAPTEVNT register).
• If enabled in the CPC700 interrupt controller, the capture timer interrupt will be sent to the processor.
9.2.3 Compare Timers
Each of the five compare timers (GPTCOMP0-4) is 32 bits wide and provides a reference value which is
compared to the TBC. The compare timer continually compares its 32-bit programmed value with the TBC
value on a bit by bit basis. Each compare timer has a corresponding mask register (GPTMASK0-4) that
allows the masking of individual bits during the compare. A valid comparison is forced for the mask bits set.
If the corresponding GPT Interrupt Mask (GPTIM) Register bit is disabled (0), and when all bits either com-
pare or are masked, the GPT Interrupt Status (GPTIS) Register bit is set, indicating a valid comparison.
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 compare event can be
used to interrupt the processor. See Figure 49 for the Compare Timer Logic/Block Diagram.
.
Figure 49. Compare Timer Logic/Block Diagram
9.2.3.1 Compare Timers Interrupt
The following steps must happen in order for a compare timer interrupt to occur.
• The corresponding Compare Timer Register (COMPx) must be programmed to the desired compare
value.
• The corresponding Time Base Counter Mask Register (MASKx) must be programmed with the desired
mask bit pattern
• The corresponding Interrupt Mask bit must be reset (0) in the GPT Interrupt Mask (GPTIM) Register
Time Base Counter (TBC)
Compare Register (COMPx)
Compare Mask (MASKx)
XOR
Valid_Compare (1/5)
Reduction
Bitters
Compare
Interrupt Mask (GPTIM)
Interrupt Enable (GPTIE)
Interrupt Status (GPTIS)
Compare Int.
(1/5) to
Int. Controller
OR
Summary of Contents for CPC700
Page 10: ...Table of Contents x Table of Contents...
Page 16: ...Tables xvi List of Tables...
Page 28: ...1 12 CPC700 User s Manual Preliminary...
Page 72: ...3 36 Processor Interface...
Page 132: ...4 60 Memory Controller...
Page 184: ...5 52 PCI Interface...
Page 194: ...6 10 Clock Power Management and Reset...
Page 224: ...8 18 IIC...
Page 244: ...10 10 Interrupt Controller...
Page 246: ...I 11 2 JTAG...
Page 250: ...12 4 Processor Local Bus PLB...
Page 262: ...14 10 Register Summary...
Page 267: ...CPC700 User s Manual Preliminary...