 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
AT89LP2052 Datasheet(PDF) 10 Page - ATMEL Corporation |
|
||||||||||||||||||||||||||||||
AT89LP2052 Datasheet(HTML) 10 Page - ATMEL Corporation |
|
|
10 / 93 page  10 3547I–MICRO–6/08 AT89LP2052/LP4052 9. Restrictions on Certain Instructions The AT89LP2052/LP4052 is an economical and cost-effective member of Atmel's growing fam- ily of microcontrollers. It contains 2/4K bytes of Flash program memory. It is fully compatible with the MCS-51 architecture, and can be programmed using the MCS-51 instruction set. However, there are a few considerations one must keep in mind when utilizing certain instructions to pro- gram this device. All the instructions related to jumping or branching should be restricted such that the destination address falls within the physical program memory space of the device, which is 2K bytes for the AT89LP2052 and 4K bytes for the AT89LP4052. This should be the responsi- bility of the software programmer. For example, LJMP 7E0H would be a valid instruction for the AT89LP2052 (with 2K bytes of memory), whereas LJMP 900H would not. 9.1 Branching Instructions The LCALL, LJMP, ACALL, AJMP, SJMP, and JMP @A+DPTR unconditional branching instruc- tions will execute correctly as long as the programmer keeps in mind that the destination branching address must fall within the physical boundaries of the program memory size (loca- tions 000H to 7FFH for the AT89LP2052, 000H to FFFH for the AT89LP4052). Violating the physical space limits may cause unknown program behavior. With the CJNE [...], DJNZ [...], JB, JNB, JC, JNC, JBC, JZ, and JNZ conditional branching instructions, the same previous rule applies. Again, violating the memory boundaries may cause erratic execution. For applications involving interrupts, the normal interrupt service routine address locations of the 8051 family architecture have been preserved. 9.2 MOVX-related Instructions, Data Memory External DATA memory access is not supported in this device, nor is external PROGRAM mem- ory execution. Therefore, no MOVX [...] instructions should be included in the program. A typical 8051 assembler will still assemble instructions, even if they are written in violation of the restric- tions mentioned above. It is the responsibility of the user to know the physical features and limitations of the device being used and to adjust the instructions used accordingly. 10. System Clock The system clock is generated directly from one of two selectable clock sources. The two sources are the on-chip crystal oscillator and external clock source. No internal clock division is used to generate the CPU clock from the system clock. 10.1 Crystal Oscillator When enabled, the internal inverting oscillator amplifier is connected between XTAL1 and XTAL2 for connection to an external quartz crystal or ceramic resonator. When using the crystal oscillator, XTAL2 should not be used to drive a board-level clock. 10.2 External Clock Source The external clock option is selected by setting the Oscillator Bypass fuse. This disables the amplifier and allows XTAL1 to be driven directly by the clock source. XTAL2 may be left unconnected. 10.3 System Clock Out When the System Clock Out fuse is enabled, P3.7 will output the system clock with no division using the push-pull output mode. During Power-down the system clock will output as “1”. |
Similar Part No. - AT89LP2052 |
|
Similar Description - AT89LP2052 |
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | 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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
