Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.NET

X  

Preview PDF Download HTML

ST7285C Datasheet(HTML) 78 Page - STMicroelectronics

Part No. ST7285C
Description  8-BIT MCU FOR RDS WITH 48K ROM, 3K RAM, ADC, TWO TIMERS, TWO SPIs, I2C AND SCI INTERFACES
Download  117 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  STMICROELECTRONICS [STMicroelectronics]
Homepage  http://www.st.com
Logo 

ST7285C Datasheet(HTML) 78 Page - STMicroelectronics

Zoom Inzoom in Zoom Outzoom out
Go To Page :
/ 117 page
background image
78/117
ST7285C
5 SOFTWARE
5.1 ST7 ARCHITECTURE
The 8-bit ST7 Core is designed for high code effi-
ciency. It contains 6 internal registers, 17 main ad-
dressing modes and 63 instructions. The 6 internal
registers include 2 index registers, an accumula-
tor, a 16-bit Program Counter, a stack pointer and
a condition code register. The two Index registers
X and Y enable Indexed Addressing modes with or
without offset, along with read-modify-write type
data
manipulations.
These
registers
simplify
branching routines and data modifications.
The 16-bit Program Counter is able to address up
to 64K of ROM /EPROM memory. The 6-bit Stack
Pointer provides access to a 64-level Stack and an
upgrade to an 8-bit Stack Pointer is foreseen in or-
der to be able to manage a 256-level Stack. The
Core also includes a Condition Code Register pro-
viding 5 Condition Flags that indicate the result of
the last instruction executed.
The 17 main Addressing modes, including Indirect
Relative and Indexed addressing, allow sophisti-
cated branching routines or CASE-type functions.
The Indexed Indirect Addressing mode, for in-
stance, permits look-up tables to be located any-
where in the address space, thus enabling very
flexible programming and compact C-based code.
The 63-instruction Instruction Set is 8-bit oriented
with a 2-byte average instruction size. This In-
struction Set offers, in addition to standard data
movement and logic/arithmetic functions, byte
multiplication, bit manipulation, data transfer be-
tween Stack and Accumulator (Push/Pop) with di-
rect stack access, as well as data transfer using
the X and Y registers.
5.2 ST7 ADDRESSING MODES
The ST7 Core features 17 different addressing
modes which can be classified in 7 main groups:
The ST7 Instruction set is designed to minimize
the number of bytes required per instruction: To do
so, most of the addressing modes may be subdi-
vided in two sub-modes called long and short:
– The long addressing mode is the most powerful
because it can reach any byte in the 64kb ad-
dressing space, but the instruction is bigger and
slower than the short addressing mode.
– The short addressing mode is less powerful be-
cause it can generally only access page zero
(0000 - 00FFh range), but the instruction size is
more compact, and faster. All memory to memo-
ry instructions are only working with short ad-
dressing modes (CLR, CPL, NEG, BSET, BRES,
BTJT, BTJF, INC, DEC, RLC, RRC, SLL, SRL,
SRA, SWAP)
Both modes have pros and cons, but the program-
mer does not need to choose which one is the best:
the ST7 Assembler will always choose the best one.
Addressing Mode
Example
Inherent
nop
Immediate
ld A,#$55
Direct
ld A,$55
Indexed
ld A,($55,X)
Indirect
ld A,([$55],X)
Relative
jrne loop
Bit operation
bset
byte,#5


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72  73  74  75  76  77  78  79  80  81  82  83  84  85  86  87  88  89  90  91  92  93  94  95  96  97  98  99  100   ...More


Datasheet Download




Link URL



Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Bookmark   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn