Function details-9

8.2.9 Register access

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Title function specification

Function Obtain data transfer register pointer

Function Name［--］ CDC_GetDataPtr

No 9.1

Format

Uint32 *CDC_GetDataPtr(void)

input

none

output

none

function value

Register pointer (address value)

function

Get the data transfer register (DATATRNS) pointer.

(1) Access method

There are three types of data transfer methods for data transfer registers and MPEG registers:

• DMA transfer by SCU
• DMA transfer by CPU
• Software transfer by CPU

DMA transfers by the CPU and software transfers require longword (32-bit) access to registers. In other words, the data to be transferred is in units of long words (even words).
Longword accessed data is stored in the order of upper word and lower word. When transferring odd words of data, the lower word of the last longword access is undefined.

(2) volatile declaration

When assigning a pointer to a variable, a volatile declaration is required to prevent incorrect optimization.

example

volatile Uint32 *ptr;
ptr=CDC_GetDataPtr();

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Title function specification

Function Obtaining interrupt factor register value

Function Name［--］ CDC_GetHirqReq

No 9.2

Format

Sint32 CDC_GetHirqReq(void)

input

none

output

none

function value

Register value...See data specifications (Constant) for bit names.

function

Get the value of the interrupt factor register (HIRQREQ).

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Title function specification

Function Clearing the interrupt factor register

Function Name［--］ CDC_ClrHirqReq

No 9.3

Format

void CDC_ClrHirqReq(Sint32 bitpat)

input

bitpat: Clear bit pattern (set the bits you want to clear to 0, and set the others to 1)

output

none

function value

none

function

Clears the interrupt factor register according to the specified bit pattern.

remarks

The CMOK flag in the interrupt factor register is used by the CD communication interface, so clearing it by the application program is prohibited. Also, the DCHG flag is cleared by the BOOT ROM when checking the disk, so do not clear it when initializing the application program. (As an exception, it can be cleared only during DCHG interrupt processing.)

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Title function specification

Function Obtain interrupt mask register value

Function Name［--］ CDC_GetHirqMsk

No 9.4

Format

Sint32 CDC_GetHirqMsk(void)

input

none

output

none

function value

Register value...See data specifications (Constant) for bit names.

function

Get the value of the interrupt mask register (HIRQMSK).

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Title function specification

Function Setting the interrupt mask register

Function Name［--］ CDC_SetHirqMsk

No 9.5

Format

void CDC_SetHirqMsk(Sint32 bitpat)

input

bitpat: Mask bit pattern (set the bits you want to mask to 0, and set the others to 1)

output

none

function value

none

function

Sets the interrupt mask register according to the specified bit pattern.

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Title function specification

Function Obtain MPEG register pointer

Function Name［--］ CDC_GetMpegPtr

No 9.6

Format

Uint32 *CDC_GetMpegPtr(void)

input

none

output

none

function value

Register pointer (address value)

function

Gets the pointer to the MPEG register (MPEGRGB).
The MPEG register is accessed in the same way as the data transfer register. For precautions, see Obtaining the data transfer register pointer ( CDC_GetDataPtr ).