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參數(shù)資料
| 型號(hào)： | HD66421 |
| 廠商： | Hitachi,Ltd. |
| 英文描述： | (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD) |
| 中文描述： | （內(nèi)存提供160通道4級(jí)灰度的點(diǎn)陣圖形液晶顯示驅(qū)動(dòng)程序） |
| 文件頁數(shù)： | 22/46頁 |
| 文件大小： | 201K |
| 代理商： | HD66421 |
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Preliminary
Rev. 1.1E '99.02.10
HD66421
Access to Internal Registers and Display RAM
Access to Internal Registers by the MPU:
The
internal registers includes the index register and
data registers. The index register can be accessed
by driving both the CS and RS signals low. To
access a data register, first write its register
number ID to the index register with RS set to 0,
and then access the data register with RS set to 1 .
Once written, the register number is held until it
is rewritten, enabling the same register to be
consecutively accessed without having to rewrite
to the register number for each access. Some data
registers contain unused bits; they should be set
to 0. Note that all data registers except the display
memory access register can only be written to.
Access to Display RAM by the MPU:
To access
the display RAM, first write the RAM address
desired to the X address register (R2) and the Y
address register (R3). Then read/write the display
memory access register (R4). Memory access by
the MPU is independent of memory read
by the HD66421 and is also asynchronous with
the HD66421's clock, thus enabling an interface
independent of HD66421's internal operations.
However, when reading. data is temporarily
latched into a H66421's buffer and then output
next time, a read is performed in a subsequent
cycle. This means that a dummy read is necessary
after setting X and Y addresses. The memory
read sequence is shown in figure 16.
X and Y addresses are automatically incremented
after each memory access according to the INC
bit value in control register 2; therefore, it is not
necessary to update the addresses for each access.
Figure 16 shows two cases of incrementing
display RAM address. When the INC bit is 0, the
Y address will be incremented up to H'7F with
the X address unchanged. However, actual
memory is valid only within H'00 to H'4F;
accessing an invalid address is ignored. When the
INC bit is 1 , the X address will be incremented
up to H'27 or H'35 according to WLS bit with the
Y address unchanged. After address H'27 or
H'35, the X address will be returned to H'00;
accessing more than forty bytes causes rewriting
to the same address.
[n]
[m]
Data[n,m]
Data[n,m+1]
Undetermined
H'02
H'03
H'04
WR
Input
data
Output
data
Dummy
read
[n,*]
[n,m]
[n,m+1]
[n,m+2]
[*,*]
Address
RS
RD
Figure 16 Display RAM read sequence
X Address
Y Address
22
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| HD66421TB0 | (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD) |
| HD66503 | 240-Channel Common Driver with Internal LCD Timing Circuit(帶內(nèi)部LCD定時(shí)電路的240通道驅(qū)動(dòng)器) |
| HD66520T | 160-Channel 4-Level Grayscale Display Column Driver with Internal Bit-Map RAM(點(diǎn)陣圖形LCD160通道驅(qū)動(dòng)器) |
| HD66522 | 160-Channel Column Driver with Internal Bit-Map RAM for Reflective Color Display and Grayscale Display(點(diǎn)陣圖形LCD160通道驅(qū)動(dòng)器) |
| HD66523R | 240-Channel Common Driver with Internal LCD Timing Circuit(帶內(nèi)部LCD定時(shí)電路的240通道驅(qū)動(dòng)器) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| HD66421TB0 | 制造商:Renesas Electronics Corporation 功能描述: |
| HD66503 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LCD Display Driver |
| HD66520 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LCD Display Driver |
| HD66520T | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LCD Display Driver |
| HD66520TA0 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LCD Display Driver |
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