 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
SH79F6489P/080PR Datasheet(PDF) 25 Page - SINOWEALTH Electronic Ltd |
|
|
|||||||||||||||||||||||||||||
SH79F6489P/080PR Datasheet(HTML) 25 Page - SINOWEALTH Electronic Ltd |
|
|
25 / 152 page  SH79F6488/SH79F6489 25 7.2 RAM 7.2.1 Features SH79F6488/SH79F6489 provides both internal RAM and external RAM for random data storage. The internal data memory is mapped into four separated segments: The Lower 128 bytes of RAM (addresses 00H to 7FH) are directly and indirectly addressable. The Upper 128 bytes of RAM (addresses 80H to FFH) are indirectly addressable only. The Special Function Registers (SFR, addresses 80H to FFH) are directly addressable only. The 2304 bytes of external RAM(addresses 00H to 8FFH) are indirectly accessed by MOVX instructions. The Upper 128 bytes occupy the same address space as SFR, but they are physically separate from SFR space. When an instruction accesses an internal location above address 7FH, the CPU can distinguish whether to access the upper 128 bytes data RAM or to access SFR by different addressing mode of the instruction. Note: the unused address is unavailable in SFR. 0900H 7FH 80H FFH FFH 80H Upper 128 bytes Internal Ram indirect accesses Lower 128 bytes Internal Ram direct or indirect accesses Extenal RAM 08FFH Special Function Register direct accesses LCD RAM 0923H 00H 00H The Internal and External RAM Configuration The SH79F6488/SH79F6489 provides traditional method for accessing of external RAM. Use MOVXA, @Ri or MOVX @Ri, A; to access external low 256 bytes RAM; MOVX A, @DPTR or MOVX @DPTR, A also to access external 256 bytes RAM. In SH79F6488/SH79F6489 the user can also use XPAGE register to access external RAM only with MOVX A, @Ri or MOVX @Ri, A instructions. The user can use XPAGE to represent the high byte address of RAM above 256 Bytes. But SH79F6488/SH79F6489 only has 256 bytes external RAM, XPAGE must be set as 0. In Flash SSP mode, the XPAGE can also be used as sector selector (Refer to SSP Function). 7.2.2 Registers Table 7.3 Data Memory Page Register F7H Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 XPAGE XPAGE.7 XPAGE.6 XPAGE.5 XPAGE.4 XPAGE.3 XPAGE.2 XPAGE.1 XPAGE.0 R/W R/W R/W R/W R/W R/W R/W R/W R/W Reset Value (POR/WDT/LVR/PIN) 0 0 0 0 0 0 0 0 Bit Number Bit Mnemonic Description 7-0 XPAGE[7:0] RAM Page Selector |
|
Link URL |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link to Datasheet | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| 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 Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
New Zealand ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
