參數(shù)資料
型號： HD4048212R
廠商： Hitachi,Ltd.
英文描述： AS Microcomputer Incorporating a LCD controller/Driver Circuit(帶LCD控制/驅(qū)動電路的微計算機)
中文描述： 由于微機安裝有LCD控制器/驅(qū)動電路（帶液晶控制/驅(qū)動電路的微計算機）
文件頁數(shù)： 114/147頁
文件大小： 519K
代理商： HD4048212R
HD404829R Series
114
Notes on PROM Programming
Principles of Programming/Erasure:
A memory cell in a ZTAT microcomputer is the same as an
EPROM cell; it is programmed by applying a high voltage between its control gate and drain to inject hot
electrons into its floating gate. These electrons are stable, surrounded by an energy barrier formed by an
SiO
2
film. The change in threshold voltage of a memory cell with a charged floating gate makes the
corresponding bit appear as 0; a cell whose floating gate is not charged appears as a 1 bit (figure 98).
The charge in a memory cell may decrease with time. This decrease is usually due to one of the following
causes:
Ultraviolet light excites electrons, allowing them to escape. This effect is the basis of the erasure
principle.
Heat excites trapped electrons, allowing them to escape.
High voltages between the control gate and drain may erase electrons.
If the oxide film covering a floating gate is defective, the electron erasure rate will be greater. However,
electron erasure does not often occur because defective devices are detected and removed at the testing
stage.
Control gate
Floating gate
Drain
SiO
2
Source
N
N
+
+
Control gate
Floating gate
Drain
SiO
2
Source
N
N
+
+
Erasure (1)
Write (0)
Figure 98 Cross-Sections of a PROM Cell
PROM Programming:
PROM memory cells must be programmed under specific voltage and timing
conditions. The higher the programming voltage V
PP
and the longer the programming pulse t
PW
is applied,
the more electrons are injected into the floating gates. However, if V
PP
exceeds specifications, the pn
junctions may be permanently damaged. Pay particular attention to overshooting in the PROM
programmer. In addition, note that negative voltage noise will produce a parasitic transistor effect that may
reduce breakdown voltages.
The ZTAT microcomputer is electrically connected to the PROM programmer by a socket adapter.
Therefore, note the following points:
Check that the socket adapter is firmly mounted on the PROM programmer.
Do not touch the socket adapter or the LSI
during the programming. Touching them may affect the quality of the contacts, which will cause
programming errors.
相關(guān)PDF資料
PDF描述
HD4074829 AS Microcomputer Incorporating a LCD controller/Driver Circuit(帶LCD控制/驅(qū)動電路的微計算機)
HD404828R AS Microcomputer Incorporating a LCD controller/Driver Circuit(帶LCD控制/驅(qū)動電路的微計算機)
HD404829R AS Microcomputer Incorporating a LCD controller/Driver Circuit(帶LCD控制/驅(qū)動電路的微計算機)
HD4048412 4-Bit Single-Chip Microcomputer
HD4048412FS 4-Bit Single-Chip Microcomputer
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HD4048212RFS 制造商:RENESAS 制造商全稱:Renesas Technology Corp 功能描述:AS Microcomputer Incorporating a LCD controller/Driver Circuit
HD4048212RH 制造商:RENESAS 制造商全稱:Renesas Technology Corp 功能描述:AS Microcomputer Incorporating a LCD controller/Driver Circuit
HD4048212RTF 制造商:RENESAS 制造商全稱:Renesas Technology Corp 功能描述:AS Microcomputer Incorporating a LCD controller/Driver Circuit
HD4048212TF 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Microcontroller
HD404828FS 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Microcontroller
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