Electronic component search and free download site.
Transistors,MosFET ,Diode,Integrated circuits

ST92124JCV2TC データシートの表示(PDF) - STMicroelectronics

部品番号コンポーネント説明メーカー
ST92124JCV2TC 8/16-BIT SINGLE VOLTAGE FLASH MCU FAMILY WITH RAM, E³ ™ (EMULATED EEPROM), CAN 2.0B AND J1850 BLPD ST-Microelectronics
STMicroelectronics ST-Microelectronics
ST92124JCV2TC Datasheet PDF : 429 Pages
First Prev 41 42 43 44 45 46 47 48 49 50 Next Last
ST92F124/F150/F250 - DEVICE ARCHITECTURE
2.6 ADDRESS SPACE EXTENSION
To manage 4 Mbytes of addressing space, it is
necessary to have 22 address bits. The MMU
adds 6 bits to the usual 16-bit address, thus trans-
lating a 16-bit virtual address into a 22-bit physical
address. There are 2 different ways to do this de-
pending on the memory involved and on the oper-
ation being performed.
2.6.1 Addressing 16-Kbyte Pages
This extension mode is implicitly used to address
Data memory space if no DMA is being performed.
The Data memory space is divided into 4 pages of
16 Kbytes. Each one of the four 8-bit registers
(DPR[3:0], Data Page Registers) selects a differ-
ent 16-Kbyte page. The DPR registers allow ac-
cess to the entire memory space which contains
256 pages of 16 Kbytes.
Data paging is performed by extending the 14 LSB
of the 16-bit address with the contents of a DPR
register. The two MSBs of the 16-bit address are
interpreted as the identification number of the DPR
register to be used. Therefore, the DPR registers
Figure 27. Addressing via DPR[3:0]
are involved in the following virtual address rang-
es:
DPR0: from 0000h to 3FFFh;
DPR1: from 4000h to 7FFFh;
DPR2: from 8000h to BFFFh;
DPR3: from C000h to FFFFh.
The contents of the selected DPR register specify
one of the 256 possible data memory pages. This
8-bit data page number, in addition to the remain-
ing 14-bit page offset address forms the physical
22-bit address (see Figure 27).
A DPR register cannot be modified via an address-
ing mode that uses the same DPR register. For in-
stance, the instruction “POPW DPR0” is legal only
if the stack is kept either in the register file or in a
memory location above 8000h, where DPR2 and
DPR3 are used. Otherwise, since DPR0 and
DPR1 are modified by the instruction, unpredicta-
ble behaviour could result.
DPR0
MMU registers
DPR1
DPR2
DPR3
16-bit virtual address
00
01
10
11
2 MSB
8 bits
14 LSB
22-bit physical address
44/429
9
Direct download click here

 

Share Link : 
All Rights Reserved© datasheetq.com 2015 - 2019  ] [ Privacy Policy ] [ Request Datasheet  ] [ Contact Us ]