NEC uPD72257, Preliminary User'S Manual

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Preface
Readers This manual is intended for users who want to understand the functions of this
graphics controller.
Purpose This manual presents the hardware manual for this graphics controller.
Organization This system specification describes the following sections:
• Pin function
• Functions of each building block
Module instances
These graphic controllers may contain several instances of a dedicated module.
In general the different instances of such modules are identified by the index "n",
where "n" counts from 0 to the number of instances minus one.
Legend Symbols and notation are used as follows:
• Weight in data notation: Left is high order column, right is low order
column
• Active low notation: xxx (pin or signal name is over-scored) or /xxx
(slash before signal name)
• Memory map address: High order at high stage and low order at low
stage
Note Additional remark or tip
Caution
Item deserving extra attention
Numeric notation • Binary: xxxx or xxx
B
or xxxB
• Decimal: xxxx
• Hexadecimal: xxxx
H
or xxxxH or 0x xxxx
Prefixes representing powers of 2 (address space, memory capacity):
•
K (kilo): 2
10
= 1024
•
M (mega): 2
20
= 1024
2
= 1,048,576
•
G (giga): 2
30
= 1024
3
= 1,073,741,824
Data units • Byte: 8 bit
• Half-word: 2 byte = 16 bit
• Word: 2 half-words = 4 byte = 32 bit
Register contents X, x = don’t care
Diagrams Block diagrams do not necessarily show the exact wiring in hardware but the
functional structure.
Timing diagrams are for functional explanation purposes only, without any
relevance to the real hardware implementation.
Terms and
abbreviations
Following terms and abbreviations are used:
• I/F: is short for "interface"
• S/W: is short for "software"
• H/W: is short for "hardware"
• bpp: "bits per pixel" is the number of bits holding the colour
information of a single pixel
Preliminary User's Manual S19203EE1V3UM00
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