Motorola MCF5282, MCF5281 user manual DMA Timer Event Registers DTERn, 3describes the DTXMRn fields

Models: MCF5282 MCF5281

1 816
Download 816 pages 28.97 Kb
Page 452
Image 452

DMA Timer Programming Model

Table 21-3describes the DTXMRn fields.

 

 

 

Table 21-3. DTXMRn Field Descriptions

 

 

 

 

Bits

Name

 

Description

 

 

 

7

DMAEN

DMA request. Enables DMA request output on counter reference match or capture edge event.

 

 

0

DMA request disabled

 

 

1

DMA request enabled

 

 

 

6–1

Reserved, should be cleared.

 

 

 

0

MODE16

Selects the increment mode for the timer. MODE16 = 1 is intended to exercise the upper bits of the 32-bit timer

 

 

 

in diagnostic software without requiring the timer to count through its entire dynamic range. This bit puts

 

 

 

the timer in a 16-bit mode in which only the upper 16 bits of the DTCN, DTRR, and DTCR are applicable

 

 

 

to the timer function.

 

 

0

Increment timer by 1

 

 

1

Increment timer by 65,537

 

 

 

 

21.2.8 DMA Timer Event Registers (DTERn)

DTERs, shown in Figure 21-4,reports capture or reference events by setting DTERn[CAP] or DTERn[REF]. This reporting is done regardless of the corresponding DMA request or interrupt enable values, DTXMRn[DMAEN] and DTMRn[ORRI,CE].

Writing a 1 to either DTERn[REF] or DTERn[CAP] clears it (writing a 0 does not affect bit value); both bits can be cleared at the same time. If configured to generate an interrupt request, the REF and CAP bits must be cleared early in the interrupt service routine so the timer module can negate the IRQn request signal to the interrupt controller. If configured to generate a DMA request, the processing of the DMA data transfer automatically clears both the REF and CAP flags via the internal DMA ACK signal.

Field

Reset

R/W Address

7

2

1

0

 

REF

CAP

 

 

 

 

0000_0000

R/W (ones clear/zeros have no effect)

IPSBAR + 0x403 (DTER0); + 0x443 (DTER1); 0x483 (DTER2); + 0x4C3 (DTER3)

Figure 21-4. DTERn Bit Definitions

21-6

MCF5282 User’s Manual

MOTOROLA

Page 452
Image 452
Motorola MCF5282, MCF5281 DMA Timer Event Registers DTERn, 3describes the DTXMRn fields, DTXMRn Field Descriptions