欢迎访问ic37.com |
会员登录 免费注册
发布采购

VCT3801A 参数 Datasheet PDF下载

VCT3801A图片预览
型号: VCT3801A
PDF下载: 下载PDF文件 查看货源
内容描述: 视频/控制/图文电视IC系列 [Video/Controller/Teletext IC Family]
分类和应用: 电视
文件页数/大小: 172 页 / 2219 K
品牌: MICRONAS [ MICRONAS ]
 浏览型号VCT3801A的Datasheet PDF文件第46页浏览型号VCT3801A的Datasheet PDF文件第47页浏览型号VCT3801A的Datasheet PDF文件第48页浏览型号VCT3801A的Datasheet PDF文件第49页浏览型号VCT3801A的Datasheet PDF文件第51页浏览型号VCT3801A的Datasheet PDF文件第52页浏览型号VCT3801A的Datasheet PDF文件第53页浏览型号VCT3801A的Datasheet PDF文件第54页  
VCT 38xxA  
ADVANCE INFORMATION  
3.5.2. Memory Organization  
The memory organization depends on available SRAM  
size. If external SRAM is not available, there is only  
one display bank for OSD and teletext and the page  
memory starts at a different location (see Table 3–1).  
The upper end of the memory is defined by the SRAM  
size, the lower end can be defined with the  
PAGE_MEMORY command. Default memory organi-  
zation is shown in Fig. 3–4.  
3.5.3. Page Table  
08 00 00 = 4Mbit  
SRAM  
The memory management is based on a fixed size  
page table, which has entries for every hexadecimal  
page number from 100 to 8FF. The page table starts  
with page 800 and contains a 2-Byte page pointer for  
every page.  
02 00 00 = 1Mbit  
The page table can be read with the command  
READ_PAGE_INFO sending the page number and  
reading the 2-Byte page pointer containing:  
Page Memory  
– SRAM pointer  
– cycle flag  
n x 1 kByte  
00 80 00 = 256Kbit  
– memory flag  
– subpage flag  
– update flag  
– protection flag  
00 40 00  
Display Bank  
The SRAM pointer gives the location where the page  
is stored in memory. The page size is fixed to 1 kByte,  
only ghost rows are allocated dynamically.  
4 kBytes  
00 30 00  
TTX Display Bank  
The cycle flag will be set as soon as this page is  
detected in the transmission cycle even if it cannot be  
stored in memory. Only if the page is really stored in  
memory, the memory flag will be set. The subpage flag  
will be set for every page in cycle if the page subcode  
is different from 0000H or 3F7FH. The update flag is  
set every time a page is stored and will be reset only  
for the display page after updating the display memory.  
A page with protection flag set will never be removed  
from memory.  
4 kBytes  
00 20 00  
Acquisition  
Scratch  
4 kBytes  
00 10 00  
Page Table  
4 kBytes  
The memory manager uses page priorities to decide  
which pages should be stored or removed from mem-  
ory. If no more memory is available, pages with lowest  
priority are removed automatically and the higher prior-  
ity pages are stored at their place. By setting the page  
priority the programmer has control over the memory  
management.  
00 00 00  
Fig. 3–4: Memory organization  
Table 3–1: Memory Organisation  
Memory  
Segment  
Address  
SRAM Size  
128k 19k 16k  
The page table is fully controlled by the memory man-  
ager and should never be written by external software.  
To change the page table flags the command  
CHANGE_PAGE_INFO can be used.  
3k  
Display Bank  
TTX Bank  
h’3000 h’4000 h’3000 h’0000  
h’2000 h’4000 h’3000 h’0000  
h’0000 h’0000 h’0000 no  
h’1000 h’1000 h’1000 no  
h’4000 h’1800 h’1800 no  
Page Table  
Acquisition Scratch  
Page Memory  
50  
Micronas  
 复制成功!