// entire_field = 1 ,pack32 = 1 ,First_Header 缓存地址 ,pixel = 858 lines = 525
// 这个函数是ADSP 安装程序的BF561 Video Input-Output (C)程序 运行后能正常读取First_Header 中的视频内容
void InitPPI0(bool entire_field, bool pack32, tDMA_descriptor* First_Header, short pixel, short lines)
{
short transfer_length_bytes = ((pack32) ? 4 : 1);
// configure PPI0 - not enabled yet
*pPPI0_CONTROL = (entire_field << 2) | FLD_SEL | (pack32 << 7)| (pack32 << 8);
*pPPI0_FRAME = lines;
ssync();
// configure DMA for PPI0 - not enabled yet 429
*pDMA1_0_X_COUNT = pixel * sizeof(short) / transfer_length_bytes; // 2 bytes for each pixel, count divided by four if 32-bit DMA transfers are done
*pDMA1_0_Y_COUNT = lines; // 525 507
*pDMA1_0_X_MODIFY = transfer_length_bytes; // 步长 4
*pDMA1_0_Y_MODIFY = transfer_length_bytes; // 步长 4
*pDMA1_0_NEXT_DESC_PTR = First_Header;
*pDMA1_0_CONFIG = 0x7000 | 0x0400 | DI_EN | DMA2D | (pack32 << 3) | WNR;
ssync();
}
然后，我想只读取 前面100行数据
// entire_field = 1 ,pack32 = 1 ,First_Header 缓存地址 ,pixel = 858 lines = 100 (改)
void InitPPI0(bool entire_field, bool pack32, tDMA_descriptor* First_Header, short pixel, short lines)
{
short transfer_length_bytes = ((pack32) ? 4 : 1);
// configure PPI0 - not enabled yet
*pPPI0_CONTROL = (entire_field << 2) | FLD_SEL | (pack32 << 7)| (pack32 << 8);
// *pPPI0_FRAME = lines;
*pPPI0_FRAME = 525;
ssync();
// configure DMA for PPI0 - not enabled yet 429
*pDMA1_0_X_COUNT = pixel * sizeof(short) / transfer_length_bytes; // 2 bytes for each pixel, count divided by four if 32-bit DMA transfers are done
*pDMA1_0_Y_COUNT = lines; // 525 507
*pDMA1_0_X_MODIFY = transfer_length_bytes; // 步长 4
*pDMA1_0_Y_MODIFY = transfer_length_bytes; // 步长 4
*pDMA1_0_NEXT_DESC_PTR = First_Header;
*pDMA1_0_CONFIG = 0x7000 | 0x0400 | DI_EN | DMA2D | (pack32 << 3) | WNR;
ssync();
}
但输出的数据是乱码 请高手分析下，还需要改哪些地方?谢谢
您的位置：
2012/9/3 17:42:51
