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CN8474AEPF 参数 Datasheet PDF下载

CN8474AEPF图片预览
型号: CN8474AEPF
PDF下载: 下载PDF文件 查看货源
内容描述: 多通道同步通信控制器( MUSYCC ™ ) [Multichannel Synchronous Communications Controller (MUSYCC?)]
分类和应用: 通信控制器
文件页数/大小: 221 页 / 2104 K
品牌: CONEXANT [ CONEXANT SYSTEMS, INC ]
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6.0 Basic Operation  
CN8478/CN8474A/CN8472A/CN8471A  
6.3 Channel Operation  
Multichannel Synchronous Communications Controller (MUSYCC™)  
6.3.4 Interrupt Queue Descriptor  
#define BYTES_PER_INT_DESCR 4 /* recall, dword = 32-bits or 4 bytes */  
#define NUM_INT_DESCR_NEEDED 10 /* assumption (min = 2, max = 32768) */  
#define SIZE_OF_INTERRUPT_QUEUE (BYTES_PER_INT_DESCR * NUM_INT_DESCR_NEEDED)  
#define INT_QUEUE_BOUNDARY 4  
/* local variables */  
unsigned long *pIntQueue;  
unsigned long IntQueueLen;  
pIntQueue = malloc( SIZE_OF_INTERRUPT_QUEUE + INT_QUEUE_BOUNDARY );  
pIntQueue = (pIntQueue + INT_QUEUE_BOUNDARY) & ~(INT_QUEUE_BOUNDARY – 1);  
/* interrupt queue pointers must be a dword aligned address */  
/* above, there is enough space to first move forward 4 bytes, then */  
/* lop off the 4 automatically. This will bring the pointer back */  
/* to the original address or give us the next 4 byte boundary address */  
/* IMPORTANT NOTE: be sure to save away the original pointer returned by the */  
/* memory access routine as that same value will be required to free the space.  
*/  
IntQueueLen = NUM_INT_DESCR_NEEDED - 1; /* 0-based */  
GroupStr0.IntQueueDescr[0] = pIntQueue;  
GroupStr0.IntQueueDescr[1] = IntQueueLen;  
/* either write directly into MUSYCC register - or - use a service request */  
/* for this descriptor, 2 dwords need to be written, so 2 write accesses */  
*(MUSYCC_FUNC_0_BAR + INT_QUEUE_POINTER_OFFSET)= GroupStr0.IntQueueDescr[0];  
*(MUSYCC_FUNC_0_BAR + INT_QUEUE_LENGTH_OFFSET) = GroupStr0.IntQueueDescr[1];  
The components of the Interrupt Queue Descriptor are listed in Table 6-3.  
Table 6-3. Example—Components of Interrupt Queue Descriptor  
Component of  
Descriptor  
Descriptor  
Value of Components  
Interrupt  
Queue  
IQPTR  
pIntQueue, provided by memory allocation functions and adjusted to  
be dword bound  
Descriptor  
IQLEN  
IntQueueLen, specified by #define (0-based)  
6-12  
Conexant  
100660E  
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