參數(shù)資料
型號: HD66420TA0
廠商: Hitachi,Ltd.
英文描述: LCD Display Driver
中文描述: 液晶顯示驅(qū)動程序
文件頁數(shù): 23/52頁
文件大?。?/td> 167K
代理商: HD66420TA0
HD66420
23
Table 5 Grayscale Levels (GRAY= 1)
DB7, 5, 3, 1
DB6, 4, 2, 0
Grayscale Level
0
0
0
1
1/3
1
0
2/3
1
1
Access to Internal Registers and Display RAM
Access to Internal Registers by the MPU:
The internal registers include 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 HD66420 and is also
asynchronous with the HD66420’s clock, thus enabling an interface independent of HD66420’s internal
operations.
However, when reading. data is temporarily latched into a H66420’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 12.
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 13 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.
相關(guān)PDF資料
PDF描述
HD66421 (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD)
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定時電路的240通道驅(qū)動器)
HD66520T 160-Channel 4-Level Grayscale Display Column Driver with Internal Bit-Map RAM(點陣圖形LCD160通道驅(qū)動器)
HD66522 160-Channel Column Driver with Internal Bit-Map RAM for Reflective Color Display and Grayscale Display(點陣圖形LCD160通道驅(qū)動器)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HD66421 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:(RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD)
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